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—” Sept. 1983

ATOLL RESEARCH
BULLETIN

Pans

Bae

a eT
en <a

a
260. A model for the development of types of atolls and 267. Avifauna of the southwest Islands of Palau
fs volcanic islands on the Pacific lithospheric plate by John Enbring
by G.A.J. Scott and G.M. Rotondo
’ 268. R t hist ingt Bahia Salina del Sur,
261. Ecological problems associated with disruption of Senge CNG SERS Tee ara SELIG Le) Ser

Vieques Island, Puerto Rico
by Ian G. Macintyre, Bill Raymond and
Robert Stuckenrath

iS dune vegetation dynamics by Casuarina
equisetifolia L. at Sand Island, Midway Atoll
by Steven I. Apfelbaum, James P. Ludwig and

Catherine E. Ludwig 269. The invertebrates of Galeta Reef (Caribbean Panama):

262. The flora and vegetation of Swains Island A species list and bibliography
by W.A. Whistler by John Cubit and Suelynn Williams

263. Shelf margin reef morphology: A clue to major 270. Hermatypic coral diversity and reef zonation at
off-shelf sediment transport routes, Cayos Arcas, Campeche, Gulf of Mexico

Grand Cayman Island, West Indies by Terence M. Farrell, Christopher F. D’Elia,

by Harry H. Roberts Lawrence Lubbers, III, and Lawrence J. Pastor, Jr.

264. An annotated check list of the corals of :
American Samoa 271. Cay Sal Bank, Bahamas: A biologically impoverished,
by Austin E. Lamberts physically controlled environment

by Walter M. Goldberg

265. Some marine benthic algae from Christmas
Island, Line Islands 272. Henderson Island (Southeastern Polynesia):
by William J. Gilbert Summary of current knowledge

266. An account of the vegetation of Kavaratti Island, by E.R. Fosberg, M.-H. Sachet and D.R. Stoddart

Laccadives
by P. Sivadas, B. Narayanan and K. Sivaprasad

Issued by
i THE SMITHSONIAN INSTITUTION
Washington, D.C. U.S.A.

Tis j Ni be: Ro wen te asf

i tae ;

ps. 260-272

260.

261.

262.

263.

264.

265.

266.

267.

268.

269.

270.

271.

272.

A model for the development of types of atolls and volcanic
islands on the Pacific lithospheric plate
by G.A.J. Scott and G.M. Rotondo

Ecological problems associated with disruption of dune

vegetation dynamics by Casuarina equisetifolia L. at

Sand Island, Midway Atoll

by Steven I. Apfelbaum, James P. Ludwig and Catherine E. Ludwig

The flora and vegetation of Swains Island
by W.A. Whistler

Shelf margin reef morphology: A clue to major off-shelf
sediment transport routes, Grand Cayman Island, West Indies
by Harry H. Roberts

An annotated check list of the corals of American Samoa
by Austin E. Lamberts

Some marine benthic algae from Christmas Island, Line Islands
by William J. Gilbert

An account of the vegetation of Kavaratti Island, Laccadives
by P. Sivadas, B. Narayanan and K. Sivaprasad

Avifauna of the southwest Islands of Palau
by John Enbring

Recent history of a fringing reef, Bahia Salina del Sur,
Vieques Island, Puerto Rico
by Ian G. Macintyre, Bill Raymond and Robert Stuckenrath

The invertebrates of Galeta Reef (Caribbean Panama):
A species list and bibliography
by John Cubit and Suelynn Williams

Hermatypic coral diversity and reef zonation at Cayos Arcas,
Campeche, Gulf of Mexico

by Terence M. Farrell, Christopher F. D’Elia, Lawrence
Lubbers, III, and Lawrence J. Pastor, Jr.

Cay Sal Bank, Bahamas: A biologically impoverished,
physically controlled environment
by Walter M. Goldberg

Henderson Island (Southeastern Polynesia): Summary of
current knowledge
by E.R. Fosberg, M.-H. Sachet and D.R. Stoddart

Issued by
THE SMITHSONIAN INSTITUTION
Washington, D.C., U.S.A.

Sept. 1983

ACKNOWLEDGMENTS

The Atoll Research Bulletin is issued by the Smithsonian
Institution, as a part of its activity in tropical biology, to place
on record information on the biota of tropical islands and reefs,
and on the environment that supports the biota. The Bulletin is
supported by the National Museum of Natural History and is produced
and distributed by the Smithsonian Press. The editing is done by
members of the Museum staff and by Dr. D. R. Stoddart.

The Bulletin was founded and the first 117 numbers issued by the
Pacific Science Board, National Academy of Sciences, with financial
support from the Office of Naval Research. Its pages were largely
devoted to reports resulting from the Pacific Science Board's Coral
Atoll Program.

The sole responsibility for all statements made by authors of
papers in the Atoll Research Bulletin rests with them, and statements
made in the Bulletin do not necessarily represent the views of the
Smithsonian nor those of the editors of the Bulletin.

EDITORS

F. R. Fosberg
Ian G. Macintyre
M.-H. Sachet

Smithsonian Institution
Washington, D.C. 20560

Ds Re Stoddart

Department of Geography
University of Cambridge
Downing Place
Cambridge, England

ATOLL RESEARCH BULLETIN
NO. 260

A MODEL FOR THE DEVELOPMENT OF TYPES OF ATOLLS AND VOLCANIC
ISLANDS ON THE PACIFIC LITHOSPHERIC PLATE

G-A-J- ScoTT AND G-M- ROTONDO

ISSUED BY
THE SMITHSONIAN INSTITUTION
WASHINGTON, D- C-, U-S-A.

SEPTEMBER 1983

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A MODEL FOR THE DEVELOPMENT OF TYPES OF ATOLLS AND VOLCANIC
ISLANDS ON THE PACIFIC LITHOSPHERIC PLATE

by G.A.J. Scott and G.M. Rocondos

ABSTRACT

A literature review on atoll origins and volcanic island development
on the Pacific lithospheric plate is combined with bathymetric data on
the Hawaiian, Marshall, Caroline, Tuamotu and Society island chains to
produce a model which helps explain the development of all major Pacific
plate island types. This model incorporates the concept that as new
lithosphere is formed along the East Pacific Rise older crust moves
north-west towards Asia, cools and causes ocean deepening. Some distance
from the East Pacific Rise relatively fixed melting anomalies produce
volcanic island chains. In warmer waters these islands develop fringing
reefs which continue to grow to wave level as the islands are carried on
the cooling plate into deeper water. Raised volcanic island forms can
develop on arches produced by the isostatic subsidence of new magmatic
outpourings close by. As volcanic islands with fringing reefs move into
deeper water almost-atolls and finally true atolls develop. Partly
raised and raised forms result if atolls rise over minor upwarps on the
crust produced by, 1) asthenospheric bumps, 2) arch flexuring resulting
from isostatic subsidence of nearby magmatic outpourings, 3) compression
within the lithosphere alongside Pacific plate subduction zones. The
model also helps explain certain types of drowned atolls and guyots.

INTRODUCTION

This paper attempts to develop one model to explain the origins of
all major types of island found on the Pacific lithospheric plate
(Fig. 1). Literally tens of thousands of seamounts are scattered over

I apartment of Geography, University of Winnipeg, Winnipeg, R3B 2E9,
Canada.

2
Department of Geography, University of Winnipeg. Present address:
114 Melrose Ave. East, Winnipeg, R2C 0A/7.

Manuscript received Dec. 1980, revised 1982--Eds.

Ak. subduction zane
ais of ridge
es _plote boundary uncertain

fx mention ®
GORDA
PLATE

ANTARCTICA a PLATE

Figure 1. The Pacific lithospheric plate.

the surface of the Pacific plate but the majority of these igneous
monoliths appear never to have reached the ocean surface and have therefore
been preserved intact from alterations associated with subaerial weathering
and erosion. Only occasionally do Pacific seamounts break the ocean
surface forming islands. Some of these islands reflect characteristics

of the submerged seamounts but take the form of tall volcanic peaks.

More frequently they take the form of seamounts apparently truncated near
sea level, capped by carbonate deposits, and variously described as

atolls or reefs. Another striking feature of the Pacific plate is that
islands of whatever type are normally only found in the somewhat shallower
parts of the ocean near the East Pacific Rise, or where ocean temperatures
normally remain above 22°C throughout the year.

Although fewer in number volcanic islands have received much more
attention from geoscientists and geologists interested in origins and
dynamics than their carbonate counterparts the atolls. It was only
following WWII that the Pacific Science Board of the National Academy of
Sciences organized a major program into atoll research and the text,
Atoll Environment and Ecology by Harold Wiens (1962), represented a
synthesis of this work. Perhaps partial blame for this lopsided research
thrust was due to the seemingly explicable and visually more dynamic
characteristics of volcanoes as compared to the confusion and disagreement
surrounding the low, relatively featureless, atolls. Although back in
1842 Darwin proposed the simple yet elegant explanation that these
atolls resulted from the slow submergence of volcanic islands his ideas
were contested and went unproven until 1951 when drilling through the

Lie subdiction zone

Ss oo transects

~ =. _Hawaiian Is
Seo See
By pate B oy A,
2

Philippine Is ¥ \ ‘Johnson |

‘r=
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New Caledon

Figure 2. Western Pacific Ocean showing the major island groups
mentioned in the text. Profile transects along dashed lines
are shown in Figures 7 and 10-13.

carbonate platform on Eniwetok in the Marshall Islands (Fig. 2) hit
volcanic basement rock at depths exceeding 1,200 m (Ladd, 1973).
Despite Darwin's early linkage of volcanoes to atolls it was not until
the last few decades that researchers focused more critical attention on
their interwoven histories. The last ten years in particular have seen
a great increase in geoscientific research on Pacific plate atolls and
their possible links to both the horizontal and vertical movements of
seamounts. Because of the vast amount of information presently
available on the Pacific plate it is now possible to produce an atoll
development model much more complex than that inferred by Darwin's
simple subsidence model. The following discussion of island types,
literature review and island chain analyses is therefore an attempt to
formalize major current ideas on Pacific plate island origins into one

coherent dynamic working model.
PACIFIC PLATE ISLAND TYPES

In warm tropical waters capable of supporting reef environments no
less than eleven distinct island types can be differentiated (Fig. 3).
The classifications of Pacific island types by such researchers as Wiens
(1962) and Leont'yev et al. (1975) are expanded here simply in
preparation for the development of a model designed to explain why they
differ. The precursor of all other island types on the Pacific plate is
a volcanic island with no (or incomplete) fringing reef. All other
types then depend on the development of a fringing reef and then some
degree of subsidence or emergence or some combination of these two.

a) Volcanic island with no fringing reef. This island type usually
takes the form of a young "high-island". During and particularly
following the cessation of volcanic activity such cones are subjected

to rapid subaerial weathering and erosion. Fringing reefs are absent or
incomplete either because there has not yet been time for them to
develop as is the case with Hawaii, or because they are located in poor
reef growing waters such as with the Marquesas.

b) Volcanic island with fringing reef. Good reef growing conditions
and time have permitted full or almost full development of a typical
fringing reef such as that around Kusaie Island in the Carolines. If
slow subsidence occurs the reef will remain at wave level due to upward
growth, but will broaden. Volcanic activity may still occur
intermittently and subaerial erosion and island dissection continue.

c) Raised volcanic island with fringing reef. Similar to type b above
except that emergence has elevated the original reef above sea level and

a new reef forms oceanward at wave level. Oahu in the Hawaiian Islands

is such an example (McNutt and Menard, 1978). Subaerial erosion continues
to lower maximum island elevation.

d) Almost-atoll. With this type the volcano is extinct and deeply
eroded. Submergence has left one or more embayed basaltic islands and
stacks in a lagoon surrounded by a barrier reef. Good examples of this
type are Aitutaki in the Cook group and Truk in the Carolines.

e) Raised almost-atoll. If the almost-atoll undergoes uplift instead
of subsidence then the central volcanic projections remain, the lagoon
may drain and a new reef develops at wave level. An example of this is
Atiu Island in the Cook group.

f) Atoll. If the almost-atoll continues to subside the fringing reef
keeps growing to wave level while all traces of the original volcanic
core disappear below sea level. Small low islets formed from coralline
and algal rubble separate the reef from the shallow lagoon. Examples
include Arutua in the Tuamotu group and Bikini in the Marshalls. As with
Eniwetok, continued subsidence could lead to the development of a
carbonate cap exceeding 1,200 m thick.

a) Volcanic island with no fringing reef

d) e)

eg. Atiu, Cook Is.

h) Part-raised atoll (lagoon open)

g) Inundated atoll (dry only at low tide)

lagoon

eg. Pearl and Hermes Reef, Hawaiian Is.
j) Raised atoll (dried out lagoon)

eg. Nauru, Gilbert Is.

b) Volcanic island with fringing reef c)

eg. Gardner Atoll, Hawaiian Is.
k) Raised atoll (atoll form lost)

eg. Niue, east of Tonga Is.

Raised volcanic island with fringing reef

Raised almost-atoll

raised lagoon sediments

eg. Arno, Marshall Is.

i) Part-raised atoll (lagoon enclosed)

new reef

lagoon new reef

eg. Swains |, north of Samoa
Basaltic core that was

initially a volcanic island

Reef facies produced during stable

or submergence phases

Reef developed during
or following emergence phase

Arrows
Modified from Wiens (1962)

Figure 3. Island types on the Pacific lithospheric plate.
indicate relative vertical motion.
and Leont'yev et al. (1975).

g) Inundated atoll.

above sea level at low tide.
reef in the Hawaiian Islands and
Inundation of this typical atoll
reef growing conditions followed
the reef to regrow to wave level
Pleistocene low sea level stands
rise, or 3) a rate of subsidence

Part raised atoll with open lagoon.

In this type the annular reef sand bars only project
Examples of this include Pearl and Hermes

Suvorov Atoll in the Cook group.

form may be due to, 1) deterioration of
by wave planation, 2) lack of time for
following subaerial erosion during

and then rapid post glacial eustatic
too rapid for reef buildup to keep pace.

This type has the form of a

regular atoll but has been raised only a few meters with the lagoon

remaining tidal.
chain.

An example of this is Gardner Atoll in the Hawaiian
Early reports that some of these raised reefs are due to 120,000 BP

high sea level stands are not supported by more recent explanations
(McNutt and Menard, 1979). Some atolls with higher than typical reef
flats have also been attributed to this same high sea level stand, but
recent reports again do not confirm this (Curray et al., 19/70; Newell
and Bloom, 1970).

i) Part raised atoll with enclosed lagoon. Here the atoll appears
elevated sufficiently above sea level for the lagoon to be cut off and
reduced in size. Elevation may exceed ten meters. Typical examples are
Swain's Island north of Samoa and Vaitupu in the Ellice group.

j) Raised atoll with dried out lagoon. Here apparent uplift has been

in the order of tens of meters. A karst type landscape described by the
term 'makatea' results, and small ponds may form in the lower depressions
where the previous lagoon was located. Examples of this are Nauru Island
in the Gilbert group and Makatea Island in the Tuamotus.

k) Raised-atoll with typical form lost. This atoll type has been

sufficiently elevated long enough for all remnants of the typical atoll
form to be lost. Irregular uplift may have left terraces. An example
of this type is Niue Island east of Tonga.

It is recognized that many authors use other names or intermediate
examples in their descriptions of island types and specific atolls. The
eleven categories listed above serve only as indicators of important
examples, and, as the model developed at the end of this paper shows,
under ideal conditions they could be considered genetically related
along a continuum. This continuum could also include foundered island
types such as drowned atolls and guyots.

CLASSICAL VIEWS OF PACIFIC ISLAND ORIGINS

An explanation for the existence of volcanic islands on the Pacific
lithospheric plate has never been considered a problem. It is clear they
are the product of sub-oceanic and subaerial magmatic outpourings which
have built igneous seamounts rising from the ocean floor at depths of
5,000 m or more to elevations above sea level sometimes exceeding 4,000 m.
Why Pacific plate volcanoes develop at all has received considerable
recent attention and some of the possibilities will be discussed in the
next section. Origins for the many versions of atolls scattering the
central and western Pacific have differed widely however, and they
therefore constitute a more interesting topic for debate.

While Darwin was one of the first to propose a scientific explanation
for the origins of atolls, he was certainly not the last. Since his
1842 edition of "On the Structure and Distribution of Corak Reefs,"
Wharton (1897), Daly (1915), Davis (1928), Hoffmeister and Ladd (1944),
Keunen (1947), MacNeil (1954), Menard (1969, 1973) and Purdy (1974) among
others have all contributed ideas as to their origin and modification.
Darwin's well known subsidence theory postulated that a subsiding
volcanic island base was first surrounded by a fringing reef, then a
barrier reef, and finally, as the volcanic rock disappeared below sea
level, an atoll remained. Recent investigations into the structure and

development of Bikini and Eniwetok Atolls basically support Darwin's
premise that subsidence is the key factor. Drillings show that the
coralline limestone caps on both these atolls exceeds 1,220m (Ladd, 1973).
It now seems clear that the life cycle of Bikini and Eniwetok was one of
subsidence of volcanic mounds, reef building, emergence during the
Miocene, and erosion and growth during the fluctuating sea level of the
Pleistocene.

A major alternative to Darwin's ideas was Daly's "glacial-control
theory''. Rather than the island sinking, he envisaged that it was
planated during a Pleistocene low sea-level stand and then, when the sea
rose again, the reef grew to sea level giving rise to an atoll. While
Davis (1928) considered Daly's theory as the only serious rival to
Darwin's, he reasoned that if reefs were indeed killed during the glacial
low sea level stands, then cliffed headlands ought to be commonplace
along island shores inside present-day barrier reef lagoons. The
headlands are in fact singularly absent in the warmer parts of the coral
seas but become increasingly apparent towards the northern and southern
limits of present-day coral growth. At best, Daly's theory was therefore
only applicable to the marginal belt atolls (Purdy, 1974).

Hoffmeister and Ladd (1944) did not feel that barrier reefs and
atolls were genetically related in the Darwinian sense. They considered
that both simply developed through upward growth of corals at the edges
of antecedent platforms. These platforms depended on a fortuitous
combination of erosion, deposition, volcanic activity and tectonism.
Keunen (1947), recognizing the possible relationships between the theories
of Darwin and Daly, developed his own "glacially controlled subsidence
theory'’. Unfortunately his theory is difficult to accept because he
devised two mechanisms to account for the same thing. During the
Tertiary he envisaged Darwinian subsidence, but during the Pleistocene a
modified glacial control theory is required to give the same result
through the upgrowth of reefs along the edges of. truncated barrier reefs
or atolls.

MacNeil (1954) did not agree with Keunen's idea that the Tertiary
atoll was planed off during the Pleistocene and then regrew rapidly in
the Holocene. He considered that subaerial limestone solution during
the Pleistocene was the only logical explanation for the saucer shape of
atolls, and that Holocene growth simply added a "veneer" of new carbonate
to the karst landscape. This idea, fully developed by Purdy (1974)
under the title "antecedent karst", ties together the essential premise
of Darwinian subsidence and the significance of Pleistocene low sea level
karst development. There is good evidence to support this antecedent
karst theory (Bloom, 1974), and this theory accords most fully with our
present knowledge of atoll morphology. Because of the significance of
Pleistocene karst development on "emergent" island forms the topic is
discussed more fully below.

Karst and Submerged Atolls

The "swinging sea level of the Pleistocene" has been a major factor
in the morphology of modern reef complexes, although not in the sense

that Daly intended by his glacial-control planation theory. Reefs in
general were not in fact truncated at the glacial low sea level surface;
rather rugged karst landscapes were produced on the emerged limestone
terrains (Bloom, 1974). Evidence for this can be interpreted from
drowned karst features that pass below sea level on the east Pacific
continental shoreline, from the thickness of new post-glacial coral-algal
deposits, from the present morphology of atolls, and by experimentation.

Emery et al. (1954) interpreted the closed depressions at 33 to 35m
below sea level in Bikini lagoon as sinks formed by groundwater
circulation. Similar but more abundant depressions are developed to
depths of 54min the eastern part of the lagoon of the almost-atoll, Truk.
These were interpreted by Shepard (1970) as also being sinks on a glacial-
age karst plain. Purdy (1974) presents a table summarizing the work of
many other studies on antecedent solution unconformities on Holocene
carbonate platforms, and there seems little doubt that present day atoll
morphology closely reflects the karst landscape drowned by post-glacial
eustatic rise.

Experimentation with acid on limestone blocks has also given impetus
to the antecedent karst idea. Under a uniform acid shower the flat-top
of an exposed limestone block develops into a rimmed basin that is such
an excellent scale model of an atoll that MacNeil and Purdy regard the
experiment as proof that glacial-age weathering is the primary control
of present reef configuration (Purdy, 1974). The topography of the
Mariana limestone on the northern plateau of Guam mirrors this
experiment. Here the well-defined reef and lagoon facies of the limestone
have been subaerially weathered to the point that the reef facies
actually form a peripheral range of hills around a karst plateau that is
underlain by lagoon facies. Likewise, Bourrouilh (1975, 1977) examined
profiles through many atolls and comes to the same conclusion.

The significance of antecedent karst in the discussion of Pacific
island types is two-fold. First, it is clear that the present atoll
morphology is fundamentally karst induced, rather than growth induced.
Second, it illustrates the point that certain atolls may have been
subject to more rapid solution during Pleistocene low sea level periods
and that the slow rate of growth following post-glacial eustatic rise
has not yet allowed these drowned atolls to re-emerge as islands.

Drowned or submerged atolls are quite common. Tayama (1935)
considered that of the 20 shoals or banks in the Western Carolines at
least eleven are atolls drowned by tectonic subsidence. It is quite
unlikely that tectonic subsidence is sufficiently rapid to cause their
drowning, particularly as they are found under good coral growing
conditions. Rather, regrowth following the production of antecedent
karst has simply not been sufficiently rapid to raise these shoals to sea
level again. However, this mechanism could trigger the demise of atolls
in areas which, even with today's conditions, would be considered marginal
reef growing areas. A probable example of this is the shoal located at
35° N, 172°E some 1 ,250 km northwest of Kure Atoll in the Hawaiian Chain
at a depth of 60 m. It is also quite possible that truncation during

some Pleistocene low sea stands did occur to the extent that with
subsequent eustatic rise corals simply found themselves in water too deep
in the euphotic zone to survive, and the shoal stopped growing. While

this supposition tends to agree with the planation aspect of Daly's theory,
the most unlikely form that would result would be an atoll.

THE TECTONIC POSSIBILITIES

An acceptance of Darwin's atoll origin model requires the acceptance
of island subsidence. But is subsidence merely isostatic or are other
more complex factors needed to account for the great vertical displacements
required to alter volcanic island peaks into atolls with carbonate caps
as thick as 1,200 m? With all island types in mind the question of
emergence must also be addressed. Tectonic information needed to help
answer these questions include; lithospheric plate movements, lithospheric
cooling and compressions; melting anomalies (hot-spots) and volcanic
activity; asthenospheric bumps, lithospheric loading and isostatic
changes.

Lithospheric plate movements, lithospheric cooling and compressions

The earth's lithosphere is made up of seven major, and a number of
minor, rigid lithospheric plates (Fig. 1). These plates are usually in
motion relative to each other. Where plate margins separate asthenospheric
Magma upwells to form new lithosphere, and where plates collide the
denser is normally subducted below the lighter (Fig. 4). Because of the
inherent potential for fracturing along plate boundaries their
distribution tends to coincide with seismic and volcanic activity.

Volcanic activity, however, can also be associated with melting anomalies
in the thin (75-100 km) oceanic crust. For a detailed explanation as to
how mid-ocean ridges form please see Dillon (1974).

Evidence substantiating the fact that the Pacific Plate ages with
distance from the spreading centre along the East Pacific Rise comes from
a number of sources. McDougall (1971) has dated the volcanic (basaltic)
islands of the Hawaiian Chain using the potassium-argon method and found
that they increase in age towards the north-west. Each island in the
Hawaiian-Emperor Chain is presumed to have been created over a stationary
melting anomaly presently capped by the island of Hawaii (Wilson, 1963a,b;
Shaw and Jackson, 1973).

Very convincing evidence as to the older nature of the north-western
portion of the Pacific Plate comes from the study of ocean sediments
(Heezen et al., 1973). Sediments close to the East Pacific Rise are thin
or non-existent, while with distance from the rise the sediment lens
thickens. Sediments in contact with the Pacific Plate close to the Kurile
subduction zone were actually deposited in equatorial waters during the
Mesozoic (Upper Jurassic) at least 120 million year ago (Heezen &
McGregor, 1973). Rates of platal movement have also been established.

Le Pichon et al. (1973) estimate that the Pacific Plate is

underthrusting the Aleutian Trench at 6.5 cm per year, while Heezen et al.
(1973) indicate that the plate presently has a westward component of 8 cm
per year and a northward component of 2 cm per year.

A. COLLISION BETWEEN OCEANIC PLATES

volcanic island arc eg. Mariana Is

trench sea level
oceanic lithosphere oceanic lithosphere

asthenosphere

B. COLLISION BETWEEN CONTINENTAL AND OCEANIC PLATES

hoy volcanic mountain chain eg. Kamchatka

sea level
orogenic belt

oceanic lithosphere
continental plate

asthenosphere

Figure 4. Typical subduction patterns in the western Pacific.

In the discussion of the relationship between plate tectonics and
island type differences another important characteristic of ocean plates
must be stressed. The upper surfaces of ocean plates are not in fact
horizontal relative to sea level. As the hot newly-created lithospheric
plate moves away from the accreting plate boundary along the East Pacific
Rise it progressively cools and "contracts". Because this occurs at the
same time as upper asthenosphere cools and "accretes" to the lower
lithosphere surface, lithospheric thickening is the actual result. The
overall effect of this cooling, however, is to cause the ocean to deepen
with increasing distance from the East Pacific Rise and creates a sloping
of the crustal plate. Le Pichon et al. (1973) calculate that at the
East Pacific Rise average depth is 2780 m, while at 30 million years the
Pacific Plate is at a depth of 4350 m, and at 75 million years at a depth
of 5610 m. Clearly any volcanic islands or seamounts produced on the
slopes of the East Pacific Rise or over a melting anomaly will be carried
tangentially into deeper water. So regular is the rate of ocean deepening
due to lithospheric cooling with distance from the East Pacific Rise that
Sclater et al. (1971) indicate an impirical relationship between ridge
elevation and age of the crust that can be used to date crust up to 40 my
old to within 2 my.

There is no unanimity as to the time required for crustal cooling-
ocean deepening to approach zero. Sclater and Francheteau (1970) infer

that the effects of lithospheric cooling cease by the time the plate has
moved 6,000 km (approximately 75 my), while Watts and Cochran (1974)
indicate negligible cooling at 80 my. Le Pichon et al. (1973) suggest
that cooling continues beyond 75 my but is greatly reduced in rate. That
the ocean progressively deepens towards subduction zones is clear,
however, and crustal cooling may well be the principal cause. Crustal
cooling need not necessarily be regular or linear in all parts of the
Pacific plate at the same time. This is because crustal reheating at
asthenospheric bumps and fixed melting anomalies (Menard, 1973; Crough,
1978; Rotondo, 1980) can cause expansion and thinning of the plate above
with a renewed cooling-ocean deepening pattern to the north-west (Fig. 5).

Crustal Age —>

ASTHENOSPHERE
HOTSPOT

Figure 5. Inferred interaction of the lithosphere with a mid-plate
hot-spot. From the ridge to the hot-spot the lithosphere thickens and
subsides by cooling. At the hot-spot, extra heat drives the isotherms
upwards, thins the lithosphere and causes uplift. Beyond the hot-spot,
the lithosphere cools rapidly because it is thin and thus subsides as
younger lithosphere at the same depth, rather than as normal lithosphere
of the same age (dashed line). After Detrick and Crough (1978, Fig. 4).

It is obvious that if the Pacific plate is being forced north-west
to be subducted below the edge of Asia there must be considerable
compressional forces acting close to the subduction zone. Hanks (1971)
reports strong horizontal compressional stresses seaward of the Kurile
trench. Watts and Talwani (1974) call the positive gravity anomalies
seaward of many trenches "outer gravity highs" and indicate that they
correlate well with regional rises of up to a few hundred meters.
Pacific plate margins showing slight upwarps before final subduction
include areas along the Kurile, Bonin, Japan and Philippine trenches.
The outer gravity highs seaward of the southern Bonin and Mariana
trenches also correlate with regional topographic rises but they can be
explained without inferring horizontal compressional stresses (Watts and
Talwani, 1974). Topographic rises are not present along all subduction
zones. In the discussion of island forms close to subduction zones the
presence or absence of these topographic rises must be considered.

Melting anomalies and volcanic activity

All Pacific plate island types require an original volcanic base.
It is easy to envisage magmatic outpouring forming volcanic islands close
to spreading centres that then drift away from these ridges as the plate
cools and moves into deeper water. But how do we account for volcanic
islands such as Hawaii which are both young and distant from the East
Pacific Rise? A number of explanations have been proposed to explain
this phenomenon of mid-oceanic plate volcanic activity which is not
directly attributible to spreading centres along mid-oceanic ridges.
They include the 1) hot-spot theory, 2) gravitational anchors, 3)
asthenospheric bumps, and 4) slip-strike motion theory. The term "hot-
spot" is frequently used to describe the phenomenon of magma discharge
that forms line island-seamount chains on oceanic plates. Because the
term hot-spot is also often used in the more specific sense as a theory
to explain the origin of these island-seamounts, the term "melting anomaly"
(Shaw and Jackson, 1973) will frequently be used to encompass all theories
on their origin. The "hot-spot" theory depends upon the principle of a
thermal plume originating at a fixed spot beneath the surface of the
oceanic plate in the asthenosphere (Wilson, 1963; Morgan, 1965, 1972a,b).
Essentially a convection cell mechanism is operative. This in turn
causes weakness in the 100 km thick lithesphere and outpourings of magma
occur over the plume. Magma discharges from a series of closely spaced
point source vents that coalesce into a single vent as eruptions progress
in time (Jackson & Shaw, 1975). As the ocean plate moves across this
fixed hot-spot a series of volcanic seamounts results. It is most likely,
however, that volcanism is not as precise as this ideal description
infers, nor is it necessary that magmatic outpourings be aligned
perpendicular to the East Pacific Rise spreading centre (Moberly and
Larson, 1975).

Shaw and Jackson (1973) proposed that volcanic activity at the
south-eastern end of the Austral, Tuamotu and Hawaiian Chains is not the
result of fortuitous location of thermal plumes but rather is a
consequence of shear melting caused by plate motion. Once such melting
begins a dense residuum is formed and sinks. This downwelling ultimately
forms "gravitational anchors" that stabilize the anomalies and cause
inflow of fresh parent materials into the source area for the basalts.
Such gravitational anchors, they feel, provide a much more sensitive
inertial guidance system for positioning of melting anomalies.

Menard (1973) noted the close relationship between asthenospheric
bumps and the actively growing end of volcanic chains on the Pacific
Plate. He concluded that melting anomalies are located on the "updraft"
sides of positive gravity or depth anomalies and are being overridden by
moving plates. It is quite possible that this "warping" of the lithospheric
plate determines the location of the melting anomaly, which, according
to Menard (1973) would be the result of a thermal plume. Because of the
importance of asthenospheric bumps in epeirogenic uplift resulting in
raised island forms they will be discussed more fully in the next section.

Handschumaker (1973) suggested that the Emperor Seamounts may have

been formed as a result of extrusion induced by strike-slip motion.
Jackson and Shaw (1975), however, found that there is no evidence that
any significant intraplate finite strain has been imposed on the
lithosphere in the region of linear chains, so this theory is considered
unlikely to explain the linear seamount chain phenomenon.

Melting anomalies may therefore result from a number of possible
mechanisms. The very fact that they do occur, however, produces the
seamount-island chains on which atoll development depends. They also
help account for the renewed crustal cooling-subsidence phase needed for
atoll development (Fig. 5). It should be stressed that not all melting
anomalies give rise to atolls, however. No atolls are found in waters
where either cold or the simple absence of certain reef species prevent
reef development as in the Marquesas, or where certain seamounts never
reach the ocean surface. Kidd et al. (1973) indicated that there are as
many as 150 terrestrial plumes giving rise to melting anomalies so
oceanic seamounts are not the exception. While evidence indicates that
melting anomalies are relatively stationary as in the Hawaiian Emperor
Chain (Jackson et al., 1980), it is also possible that some are less
fixed, particularly where they abut other continental plates and are
subject to forces not directly attributable to their own lithospheric
plate motion.

Asthenospheric bumps

Menard (1973) was perhaps the first to fully appreciate the
relationship between the emergence of Pacific islands and broad low
"bumps" on the ocean floor. Because he attributed these bumps to an
asthenospheric surface which is not exactly level, he called them
"asthenospheric bumps". In actuality they appear as low bumps up to
several hundred metres in vertical elevation and 1,000-3,000 km in width
on the surface of the ocean plate and are detected as positive gravity
anomalies. As the plate moves over these asthenospheric bumps the
general tendency for the lithosphere to deepen due to cooling (Le Pichon
et al., 1973) is temporarily counteracted. Any islands or atolls on the
upslope side begin to rise out of the water instead of subsiding in the
expected way (Fig. 6). Ocean, Nauru and Marcus islands are good examples
of the effects of asthenospheric bump uplift on islands (McNutt and
Menard, 1978).

Asthenospheric bumps are located in many parts of the Pacific. Care
must be taken in evaluating their overall significance however. While
it is tempting to associate all seamounts and islands riding over one
asthenospheric bump with one melting anomaly, it may be that peaks
produced by another melting anomaly nearer the East Pacific Rise have
simply advanced to this new bump-melting anomaly area (Rotondo et al.,
1981). In this way the idealized sequence of atoll formation may appear
confused as high islands from the nearby melting anomaly may be
associated with atolls from another but distant melting anomaly.

Isostatic subsidence and lithospheric loading

Darwin's original atoll development model infers isostatic subsidence

LEACHING & SOLUTION

A pomp ne
ie

ASTHENOSPHERIC
BUMP

Kilometres
a=
1
oa

Figure 6. Idealized history of an atoll emerging-subsiding as it
passes over an asthenospheric bump. After Menard (1973).

due to the islands own mass. Although some atolls have been subsiding
for more than 50 ml years and have undergone subsidence exceeding 1,000 m
it is very unlikely that isostasy alone could occur over such long periods
of time. McNutt and Menard (1978) suggest that lithospheric loading by

a new volcanic island produces a response over geologic time scales of
100,000 years or more, while Watts and Cochrane (1974) state that after
only a few million years of loading isostatic adjustments approach zero
and that the ocean plate then seems capable of supporting seamount chains
for periods of tens of millions of years. Isostatic subsidence, for
newly formed volcanic islands and submerged seamounts is very real,
however, and immediately gives rise to a '"moat-arch" development (McNutt
and Menard, 1978, 1979; Jarrard and Turner, 1979).

Depression of the lithosphere by a new volcanic mass is variously
described as crustal loading or lithospheric loading, and a crustal moat
develops peripheral to the seamount. This moat may fill rapidly with
sediments and not appear on bathymetric maps. Beyond the outer edge of
the moat, flexuring develops an arch which experiences uplift in the
order of tens of metres. If there are islands at various distances from
this new loading mass those within the developing moat will experience
gradual subsidence, while those on the developing arch will be slowly
elevated. McNutt and Menard (1978) argue that the uplift of Atui,
Mitiara, Mauke and Mangaia atolls in the Cook Islands result from
lithospheric loading by three nearby volcanoes. Jarrard and Turner (1979),
while agreeing with this conclusion, disagree as to the exact amount of
resultant elevational change.

When magmatic outpourings cease above a melting anomaly and the
volcanic island "drifts'' away isostatic subsidence will soon cease.
Likewise any island over which it had an influence would continue to
move into deeper waters due to non-isostatic crustal cooling-ocean
deepening. This picture can be confused in practice, however, if a new
seamount again develops before other islands have had the opportunity to
move beyond any new moat-arch development. Likewise, atolls drifting

past a hot-spot seamount system not associated with its own igneous
pedestal development could undergo subsidence or uplift depending on
their proximity to the new crustal loading. McNutt and Menard (1978)
consider this latter mechanism explains the emergence of some Tuamotu
atolls following recent moat-arch development in the Tahiti area.

In our consideration of island types on the Pacific plate isostasy
by itself seems of minor short term influence in causing volcanic islands
to subside. Unless a volcanic island ceased growth at, or just above,
sea level an atoll could hardly result from isostatic causes alone.
Isostasy can clearly have a major influence on other island types,
however, causing increased but modest subsidence rates for existing atolls
within the new moat and emergence of atolls or volcanic islands on the
arch. Beyond the arch little or no isostatic influences will be felt
and Watts and Cochrane (1974) consider that the 400 m thick carbonate
cap on Midway could not be due to this influence.

CASE STUDIES ON SPECIFIC ISLAND CHAINS

A number of island groups are examined to show how the various
island types within them correspond to the tectonic, volcanic and reef
growing conditions known to be operating on the Pacific plate. Three
island groups in the North Pacific were examined using information from
the literature and extracting bathymetric data from maps produced by the
Scripps Institution of Oceanography (Chase et al., 1970). These island
groups are the Hawaiian, Marshall-Gilbert and Caroline. The Tuamotu and
Society Island groups in the southern hemisphere were also examined with
bathymetric data coming from a bathymetric map of the Pacific produced
by the Academy of Sciences (1964).

Hawaiian-Emperor Chain

This chain was selected because not only is it the most intensively
researched group but because it is also the best example of a continuous
line island group that runs from warm reef-promoting waters to cooler
reef-inhibiting waters. The Hawaiian-Emperor chain lies entirely within
the North Pacific and constitutes the Hawaiian Islands, the atolls and
shoals of the Midway group, and the seamounts and guyots of the Milwaukee-
Emperor chains (Fig. 7). This volcanic (basaltic) ridge runs from the
Island of Hawaii, a total of 6,340 km to the Kamchatka Trench. Figure 7
depicts the peaks and corresponding ocean floor depths from a point
south-east of Hawaii to the Kamchatka Peninsula. Data was taken from
bathymetric maps prepared by Chase et al. (1970) which use 200 fathom
depth intervals. In order to determine ocean floor depths and the
heights of peaks with respect to sea level and the ocean floor, a line
was plotted from a point south-east of Hawaii through the major peaks to
the Kamchatka Trench (see Fig. 2 for profile route). Sampling points
were placed at regular intervals along this line and data on the
elevations and depths between the closest volcanic islands, atolls or
submerged seamounts were recorded for each point. In all there were 132
points along the 6,/00 km transect and using this data a profile of the
more prominent peaks was produced (Fig. 7).

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To obtain data on sea floor depths four lines were drawn parallel to
the central ridge line at three and six centimetres to either side.
Ocean depths were recorded exactly on these parallel lines at right angles
to the 132 points on the central ridge line. The ocean floor profile in
Figure 7 is the average of these four depths for each of the 132 profile
positions. It should be noted, however, that this ocean floor curve is
not coincident with the surface of the lithospheric plate. Since the
Pacific plate was formed at the East Pacific Rise, thin layers of sediment
as well as outpourings of magma associated with the Hawaiian melting
anomaly have been superimposed on it to varying degrees. Despite the
visible bumps that result from these magmatic ourpourings, the bumps are
actually locked onto the plate as it moves into deeper water due to
lithospheric cooling with age (Le Pichon et al., 1973). Minor
asthenospheric bumps would be independent of these outpourings and could
well cause the "bobbing" motion described by Menard (1973), but they
could not be detected simply by examining bathymetric maps.

An examination of these profiles shows a number of interesting
characteristics. Following the peak-curve from the Island of Hawaii
north-west, it can be seen that the average high island elevation drops
off rapidly due to the longer exposure to subaerial erosion (Fig. 7).
There is no reason why these islands should appear to be reduced in
elevation in a linear way because the original islands were never all at
the same elevation to begin with (MacDonald and Abbott, 1970). The
majority of these high islands, however, did exceed 1,000 m before
cessation of volcanic activity, and heavy orographic precipitation
combined with high temperatures and easily weathered besalts gives rise
to rapid chemical weathering (Scott and Street, 1976). This subaerial
erosion, together with coastal erosion, combine to rapidly reduce the
elevation of islands, and this trend does appear in the profile.

The findings of Moore (1970) concerning isostatic readjustment of
the Pacific Plate to the additional load of a new volcanic island must
also be considered here because they indicate that isostatic subsidence
is not as significant as originally suggested by the Darwinian subsidence
model. According to Moore (1970) the absolute subsidence of the still-
active Island of Hawaii is 4.4 mm per year. This agrees well with Apple
and MacDonald (1966) who estimated that the west coast of Hawaii is
subsiding at 3 mm per year. Moore also indicated that Maui (0.8-1.3 my,
McDougall, 1964) is subsiding only 1.7 mm per year, Oahu (2.2-3.4 my) is
stable, and Kauai (3.8-5.6 my) is actually rising. There is of course
the real possibility that the Hawaiian chain in general will experience
subsidence as it moves north-west because it will be descending the now
cooling flank of a rise created over the Hawaiian hot-spot (Fig. 5).
This cooling is similar to that near the mid-oceanic ridge and for the
Hawaiian Islands would appear as in Figure 8. The true picture is
somewhat confused near the hot-spot because of the current moat-arch
development around Hawaii and the residual effects of Maui which must
combine to give rise to the isostatic subsidence-emergence noted by
Moore (1970) above. Oahu clearly does have a raised reef probably
resulting from the arch produced by the combined masses of Maui and the
earlier development of Hawaii. Now that Hawaii has become so massive

Oahu has stopped rising possibly because the Hawaii moat has now radiated
outwards to bring Oahu into its flanks. The emergent island of Kauai
continues to rise, however,’ as it may now have been fully overtaken by
the Hawaii arch.

The most northerly islands in the Hawaiian chain with visible
basaltic rock, Necker, La Perouse Rock and Gardner Pinnacles, are all
reduced to less than 90 m above sea level. It is unlikely that all of
this reduction results from subaerial and marine erosion alone. Each of
these islands is surrounded by extensive flat reef-shoals and all
indications are that they have undergone gradual submergence (Menard,
1973). Between Gardner Pinnacles and Kure Atoll, island and ocean floor
subsidence is clearly indicated (Fig. 7). North of Kure only one
seamount, between Jingu and Kaumu seamounts at 35°N, 172-E, is within
60 m of sea level. Apart from this peak, which must have been a
Pleistocene island, there are no peaks north of Kure that could have been
above sea level in recent times. This peak is no doubt a submerged atoll
which experienced difficulties in producing reef growth sufficient to
keep it at wave level as it continued to move into cooler waters. Karst
formation on this eustatic low-sea level island during the Pleistocene
would have encouraged this submergence relative to present sea level.

North of 35°N, WP peaks deepen in a relatively linear fashion,
and parallel deepening of the ocean bottom occurs. Close to the
Kamchatka Trench, seamount elevations are variable, the ocean floor
receives greater thicknesses of continental sediments and there appears
to be minor buckling associated with bending of the Pacific Plate as
subduction begins. This buckling effect is confirmed by Watts and
Talwani (1974) but it will only have the effect of modestly raising
deeply submerged seamounts close to the trench. Irregularities are to
be expected, however, as most seamounts never reached sea level even
when they were first formed, and at their present great depths it is
difficult to differentiate between a seamount that never reached the
ocean surface, and a guyot which may have been truncated at sea level
and subsequently subsided. The term guyot must be treated with caution
here because not all flat topped seamounts (i.e. guyots) are considered

EAST PACIFIC RISE

HAWAII

KANMU
| SUIKO

| MeWI

Figure 8. Subsidence after reheating at Hawaiian hot-spot. Hawaii
depicted at the depth of normal 25 my lithosphere. Dashed
line is expected subsidence without reheating. Modified
from Crough (1978, Fig. 16).

to have been planated at sea level. Recent corings on Ojin, Nintoku,
Yomei and Suiko seamounts in the Emperor Seamount Chain (Jackson et al.,
1980) confirm that these guyots were in fact volcanic islands before
subsidence allowed them to pick up carbonate caps. Borings on Suiko
(Fig. 7) hit a "Paleocene shallow-water reef or bank assemblage of
carbonate sand and sandy mud with algal nodules, from 52.5 to 163.5
meters. Basalt directly underlies the shallow-water limestone'! (Jackson et
al., 1980:11). Paleomagnetic measurements indicate that Suiko was formed
at approximately 25°N latitude at a time when carbonate deposition (and
possibly discontinuous reef formation) was occurring in water somewhat
cooler than around the present-day Hawaii. The paucity of coral material
on seamounts in the northern Emperor Chain is in marked contrast to
seamounts at the bend of the Hawaiian-Emperor Chain (see A4 on Fig. 2)
where corals are more abundant (Jackson et al., 1980). It appears then
that a southward movement of the Hawaiian hot-spot into warmer waters
accounts for the earlier development of bryozoan-algal caps (without
coral) to the present day coral-algal caps. Figure 8 suggests that given
time present day Hawaiian atolls will indeed become truly submerged
atolls just as this appears to have already happened to Darwin Guyot in
the Mid-Pacific Seamounts to the West (Ladd et al., 1974). This guyot
has subsided to a depth of 690 fathoms but has preserved intact the

atoll annular ring and ten-fathom deep lagoon.

On the basis of the above analysis a schematic representation of
what may well have happened to the Hawaiin-Emperor seamount chain over
the last 70 my is presented (Fig. 9). While this figure clearly
generalizes the actual profile given in Figure 7 it does exhibit a
remarkable approximation to the known facts and tectonic possibilities.
It should be noted that not only does Figure 9 account for many of the
island types illustrated in Figure 3, but it indicates four distinct
island-seamount zones or "phases". It should also be noted that but for
the fact that many of the Emperor Seamounts were formed in poor reef-
growing waters, submerged atolls would extend all the way to Kamchatka.

Marshall-Gilbert Chain

These islands differ quite markedly from the Hawaiian-Emperor chain.
They are in fact much more scattered and do not represent a characteristic
line island group. The chain also lacks almost-atolls and high volcanic
islands at its south-eastern end. Likewise there is no clear indication
that the chain continues north-west, as does the Emperor Chain, to be
subducted into a trench.

Figure 10 is based on a composite profile of the scattered atolls,
shoals and seamounts of the Marshalls, and therefore differs from the
single profile-transect method used in Figure 7, for the Hawaiian chain
(bathymetric data from Chase et al., 1970). Because of the difficulty
in interpretation of seamounts north of the Marshalls it was difficult
to decide exactly the path taken or to be taken, by the most northerly
seamounts in the chain. As a result two profiles are drawn. Both begin
on the equator (Bl on Fig. 10) and move north-northwest to Wake (B2 and
B3). Then one continues in the same direction to B4 in the deep ocean
north of the Mapmaker Seamounts. It is possible that the numerous

ZONE 4 ZONE 3 ZONE 2 ZONE! ,

Thick lens of Atolls carried under to | |
continental margin | form Guyots-guyots to |
sediments North have non-atoll

| carbonate caps only |

19°N,155°W

olcanic chain

54°N 163°E

Kspine
Te slope of pec
aC 28 N
c

sea level

asthenospheric

bump and
moat anomaly

KAMCHATKA

ASTHENOSPHERE
a. Hawaii b. Kauai c. Gardner Pinnacles
d. Midway Atoll e SuikoSeamount f. Seamount 53°N,165°E

Figure 9. Schematic representation of the major physical factors
influencing the Hawaiian-Emperor Seamount Chain (modified
from Scott et al-, 1976):

seamounts to the west and northwest may be part of the Marshall chain so
another profile continues from B3 through Marcus Island to B5 at the
Bonin Trench.

For both profiles the generalized ocean floor depth increases
towards the northwest. The members of the Gilbert group shown on the
profile are of a line island type, but appear to be separated from the
Marshalls both visibly and bathymetrically. The numerous atolls of the
Marshalls are scattered in two general lines running SSE to NNW and are
associated with numerous seamounts (not shown in Fig. 10). North of
Taongi Atoll none of the Marshall Seamounts appear to have reached sea
level. From the bathymetric map Wake Atoll would appear to result from
a different melting anomaly than that which produced the main Marshall
cluster. Marcus Island and the shoal just beside the Bonin trench
represent isolated peaks, but it is more likely they were previously
shallow drowned atolls. Marcus is now rising over an asthenospheric bump
and is now a raised atoll (McNutt and Menard, 1978). The shoal close to
the Bonin trench may have been elevated close to sea level by the outer
gravity high produced just before subduction.

In the case of the Marshalls, which must represent a senile volcanic
chain produced by a long-inoperative hot-spot, the gradual movement into
deep water combines with subaerial erosion to leave only atolls. Drillings
on Bikini and Eniwetok (Ladd, 1973) at the northern end of the Marshall
Chain hit basalt at depths exceeding 1,220 m, and shallow water fossils
taken just above the basalt basement are about 55 my old. It is therefore
quite probable that the parent volcanoes on which these atolls developed
were formed just south of the equator in shallower water. They then
collected these vast thicknesses of carbonate deposits on their slow

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journey northward. Such thicknesses are greatly in excess of those in
the northern end of the Hawaiian Chain and reflect the truly equatorial
location of their parent melting anomaly. In the Hawaiian Islands great
thicknesses of carbonate are inhibited by a much shorter passage through
reef-promoting waters between the time their basalt cores are reduced

to sea level and the time atolls suffer demise north of 30°N in cooler
waters.

Caroline Islands

The Carolines run west-northwest from Kusaie to the Mariana Trench
(Fig. 11). Like the Hawaiian-Emperor Chain there are volcanic islands
to the south-east and atolls to the west. Unlike the Hawaiian Chain,
however, the almost-atoll form is also present, and the complete chain
lies within warm tropical waters conducive to reef growth. The presence
of almost-atolls as well as young volcanic islands and atolls make the
Caroline Chain one of the more typical line island chains insofar as
island form is concerned.

A composite profile based on data taken from bathymetric maps
compiled by Chase et al. (1970) is shown in Figure 1l. As is the case
with the Marshall profile in Figure 10 the western end of the chain
appears as a confused pattern on the bathymetric maps, thus this portion
of the profile follows two separate paths (see Fig. 2 for profile routes).
Figure 1l also shows two profiles for the ocean floor, one along the
southern side of the chain and one along the northern. They are
separated because it is considered that to average these depths would be
misleading. This discrepancy may arise because the southern side of the
atoll portion of the chain on the Pacific plate appears to be under
considerable stress from the north-eastern advance of the Bismark portion
of the Australia plate and the Eauripik-New Guinea Rise. Long east-west
trenches just south of Woleai Atoll tend to support this conclusion.
Thus, depths to the south of the chain are not considered to be reliable
indicators of Pacific plate deepening as it approaches the Mariana
Trench.

It is also possible that the melting anomaly which gave rise to
these islands has been forced to migrate east as the Australia plate
slowly moves north-east. This hypothesis might help explain the more
east-west orientation of the Carolines that supposedly lies on a rigid
lithospheric plate with a northwest movement and on which most line
islands trend northwest. While deformation of the Pacific plate similar
to that found by Rea (1970) north of the Hawaiian Ridge may account for
some of this east-west trend it is unlikely to account for such a marked
departure from the normal line-island trend.

Despite these problems the Caroline Islands reflect the classical
Darwinian atoll formation sequence when superimposed on a plate moving
into deeper waters. It differs from the Hawaiian-Emperor chain sequence,
however, in that atolls do not appear to die off except where subduction
causes rapid subsidence into the Mariana Trench. Some circumstantial
evidence also suggests that as the Carolines move towards the west they
enter deeper water. While there is no reason to assume that newly-formed

islands have always been of the same size, the hypothesis presented here
would require gradual reduction in area at sea level if they were moving
into deeper water. Wiens (1962) indicated that the average dimensions
of the 15 westernmost sea-level atolls is 12.2 x 5.6 km, while the
average for those 17 to the east (in relatively shallower water) is

16.8 x 9.6 km.

Tuamotu and Society Islands

There is a total of 72 atolls in the Tuamotu Islands (Fig. 12). At
the southeastern end of the chain is a near-atoll, Mangareva, an old
volcano in a similar stage to Truk in the Carolines. Mangareva consists
of a dozen small embayed islands and stacks in a lagoon surrounded by a
well-developed barrier reef some 41 km in diameter. Pitcairn, a
relatively young volcanic island, lies 450 km to the southeast of
Mangareva. If Pitcairn was actually produced by the same melting anomaly
responsible for the Tuamotu Archipelago proper, then the Tuamotu Chain
cannot yet be considered a totally senile volcanic chain.

In the area of the Tuamotu Islands there is no doubt as to the
actual deepening of the ocean floor as it moves northwest towards the
equator. These islands are relatively close to the East Pacific Rise
where lithospheric cooling causes most rapid increases in depth (Heezen
et al., 1973), and as they move into successively more suitable reef
growing conditions atoll development conditions are optimal. The large
number and close spacing of the Tuamotu atolls is also indicative of
their origin in shallower waters close to the East Pacific Rise. On
average more of the newly formed seamounts would have reached sea level
here simply because of the shallower water.

Because of their ideal position south of the equator it is probable
that many of the larger atolls in the Tuamotu group will survive for many
millions of years during their slow passage through warm equatorial
waters. It is possible, however, that some of the smaller atolls will
suffer demise even in equatorial waters because as island bases move
into deeper water the top of their carbonate peaks will become so narrow
that they will no longer support any island form whatsoever. Data for
the Tuamoto Archipelago profile given in Figure 12, as well as for the
Society Islands (Fig. 13), were extracted from Russian bathymetric maps
of the Pacific (1:40,000,000) giving depths in 500 m intervals (Academy
of Sciences, 1964). Although it does not show up well on a profile of
this scale (Fig. 12) some of the atolls at the north-western end of the
Tuamotus are raised. While there is some disagreement as to the absolute
uplift involved there is general consensus that the uplift of Matahira,
Tikehau, Makatea, Niau and Anoa is due to arch flexuring following recent
crustal loading by Tahiti and Mahetia to the west-south-west in the
Society Islands (McNutt and Menard, 1978, 1979; Jarrard and Turner, 1979).

‘

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the Tuamotu except that they do not continue as seamounts to the north-
west as do the Hawaiian. The Society group are probably much younger
than the major portion of the Tuamotus because of their short length and
lack of subaerial erosion. They exhibit all the characteristics of a

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young island chain being subaerially eroded to sea level and being
carried progressively into deepening water where their fringing reefs
ultimately form atolls.

A MODEL FOR ISLAND-TYPE DEVELOPMENT

The following model is based on an acceptance of the idea that
successive volcanic islands are formed over relatively stationary hot-
spots on an oceanic lithospheric plate which is moving tangentially into
deeper water. Important additional considerations include, the possible
effects of asthenospheric bumps, moat-arch development due to lithospheric
loading, uplift due to outer gravity highs close to subduction zones, an
acceptance of the antecedent-karst influence on atoll form, and the
realization that upward reef growth will slow, and ultimately stop, if
it enters cool waters. Bearing these points in mind the eleven island
types given in Figure 3 can now be illustrated in one dynamic working
model (Fig. 14).

In Figure 14 new lithosphere is seen to accrete to the oceanic
plate margin along the East Pacific Rise as the plates are forced apart
by strong upwelling in the viscous asthenosphere below. With distance
from this ridge the plate cools and ocean deepening is quite rapid. The
seventeen volcanic island-atoll-submerged seamount positions north-west
of the oceanic ridge shown in Figure 14 are described below. It should
be stressed that probably no island chain actually possesses all of the
eleven island-type possibilities at one time. It is very likely,
however, that most types are found in major island chains during some
stage of their history. This model is extended to show submerged
seamounts which were former islands.

Position 1. The rigid oceanic plate overrides a hot-spot which injects
magma through the lithosphere to form a young, active volcanic island.
Isostatic subsidence creates a moat-arch flexuring of ithe crust.
Fringing reefs have not yet had time to develop.

Position 2. Relatively inactive volcanic island undergoing some residual
isostatic subsidence but sinking more rapidly due to the moat development
caused by lithospheric loading at position one. By now a fringing reef
has developed and elevation of volcanic peaks is being rapidly reduced

by subaerial erosion. Any subsidence due to tangential movement caused
by crustal cooling is minor.

Position 3. Volcanic island with complete fringing reef undergoing no
vertical change. Isostatic changes due to its own mass no longer
operate and any tangential movement-subsidence caused by crustal cooling
or any residual moat effects from position two are counteracted by arch
flexuring due to lithospheric loading at position one.

Position 4. Volcanic island undergoing uplift due to the arch flexuring
created by crustal loading at position one. The fringing reef will be
raised out of the water and a new reef develops seaward to wave level.
Subaerial erosion continues and will affect both raised reef and basalt.

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Position 5. Volcanic island undergoing subsidence due to crustal cooling-
deepening and "lee-of-arch"' deepening. Fringing reef grows upwards and
begins to form a barrier reef as the volcanic island is reduced in both
elevation and areal size.

Position 6. Almost-atoll stage. A few remnant volcanic pinnacles or
islets remain in the centre of a large lagoon partly rimmed by low reef-
rubble islands. Subsidence due to crustal cooling only. If an
asthenospheric bump (see position 9) or a lithospheric loading arch (see
position 12) develops here, we would get a raised almost-atoll.

Position 7. Crustal cooling-subsidence continues until no volcanic
remnants can be seen. Reef keeps growing to wave level and a true atoll
develops.

Position 8. Typical atoll developing a thick carbonate cap as crustal
cooling-subsidence continues. If causes for vertical movement other
than cooling-subsidence are not considered this form can be maintained
and the carbonate cap continues to thicken until it reaches either a
subduction zone or waters too cool for proper reef growth.

Position 9. Part-raised or raised atoll develops as an atoll rises up
the south-east flanks of an asthenospheric bump. No magmatic outpourings
occur. Degree of uplift determines which type of part-raised or raised
atoll will develop.

Position 10. Raised atoll or part-raised atoll descending the north-
west side of the asthenospheric bump undergoes rapid subsidence due to
crustal cooling to form a regular atoll again. (No influence of the
lithospheric-loading influencing position eleven is indicated here
although arch flexuring might in fact occur.)

Position ll. Rapid subsidence due to the moat effect of new lithospheric
loading offset from the line island chain by a short distance. Atoll
form remains intact and carbonate cap thickens quickly. Submergence
processes are essentially similar to those at position two. This could
occur at any position along the chain where a new hot-spot breaks through
or where the atoll in question moves alongside the hot-spot of another
island chain e.g. the Tuamotu atolls passing Tahiti's hot-spot.

Position 12. Part-raised or raised atoll rising rapidly due to the arch
effect generated by lithospheric loading near position eleven. Degree
of uplift again influences raised atoll form.

Position 13. Typical atoll form returns ag the island passes beyond the
moat-arch effects of positions eleven and twelve. Here subsidence is
attributable to tangential movement as the crust cools.

Position 14. An inundated or drowned atoll develops if the structure
moves into water too cool to support algal-coral populations needed to
Maintain a sinking carbonate platform at sea level. Drowned forms could
also result if rapid subsidence occurs as an atoll enters a subduction

ZONE o

Position 15. Guyot stage results when the atoll is deeply submerged.
Here submergence will be quite slow if only crustal cooling is operating.
Guyots (or atolls) near a continental or island arc margin will receive
thick sediment layers around their bases.

Position 16. Temporary uplift of guyot as it crosses the outer gravity
high just before subduction. If this had occurred while the drowned-to-
typical-atoll stages were present then a raised atoll form should
develop.

Position 17. Guyot (or atoll if still in warm waters) will be subducted
into the trench where it undergoes accretion-destruction.

CONCLUSION

It is concluded that island-types on the Pacific plate result
primarily from the subsidence of volcanic islands due to the tangential
motion of the lithospheric plate. An analysis of melting anomaly island
groups such as the Hawaiian, Caroline, Marshall, Tuamotu and Society
chains tends to confirm this conclusion, and such peculiarities as
raised or drowned atolls can be explained if asthenospheric bumps,
lithospheric loading, outer gravity highs and subaerial erosion during
Pleistocene low sea level stands are considered. The almost complete
absence of islands north of 28°N in the Pacific, other than those
attributable to plate collisions, is considered to be due to the
combined action of rapid subaerial erosion of basalts and this tangential
component. These geomorphic and tectonic processes clearly encourage
rapid subsidence of volcanic islands produced over melting anomalies,
but if their reduction to sea level occurs during passage through warm
tropical waters upward reef growth normally prevents their demise.

Rapid subduction or movement into cooler waters eventually cuases upward
reef growth to diminish and the atoll becomes submerged. Drowned atolls
and guyots may result before final subduction.

ACKNOWLEDGEMENTS

We are indebted to Dr. W. Rannie of the University of Winnipeg who
gave valuable criticisms on several drafts of this paper. We would also
like to thank Mr. G. Thomson for his excellent cartography and Mrs. V.
Hart for typing the final copy. This paper is an expansion of a paper
first delivered to the Annual Meeting of the Association of Canadian
Geographers at Laval University, Quebec, May 1976. Financial assistance
from the University of Winnipeg is acknowledged.

REFERENCES

Academy of Sciences. 1964. Skhema Otmetok glu'in morskikh
nabigatsionnikh kart 4 general'not batimetricheskot karti okeanov
(3 2 4 “&zLaniya) cspokzovannikh pri sostavlenii karti.
Mezhuvedomstvennii Geofizicheskii Komitet Prezidiume Akademii Nauk
SSSR Moskva.

Apple, R. A. and Macdonald, G. A. 1966. The rise of sea level in
contemporary times at Honaunau, Kona, Hawaii. Pacif. Scr. 20:

125-136.

Bloom, A. L. 1974. Geomorphology of reef complexes. In L. F. Laporte,
ed.: Reefs in time and space. Soc. of Econ. Paleontologists
and Mineralogists, Spec. Publ. 18: 1-8.

Bourrouilh, F. 1976. Karst, subaerial diagenesis and atolls. Reun.
Annu. Sci. Terre (Paris), 4: 73.

Bourrouilh, F. 1977. Géomorphologie de quelques atolls dits "soulevés"
du Pacifique W et SW, origine et évolution des formes recifales
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Chase, T. E., Menard, H. W. and Mammerickx, J. 19/0. Bathymetry of
the North Pacific. Scripps Inst. Oceanogr. and Inst. Mar. Resour.,
Univ. Calif., San Diego, La Jolla, Calif.

Crough, S. T. 1978. Thermal origin of mid-plate hot-spot swells.
Geophys. J. R. astn. Soc. 55: 451-469.

Curray, J. R., Shepard, F. P. and Veeh, H. H. 1970. Late Quaternary

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ATOLL RESEARCH BULLETIN
NO- 261

ECOLOGICAL PROBLEMS ASSOCIATED WITH DISRUPTION OF DUNE
VEGETATION DYNAMICS BY CASUARINA EQUISETIFOLIA L.-
AT SAND ISLAND, MIDWAY ATOLL
BY

STEVEN I- APFELBAUM, JAMES P- LUDWIG AND
CATHERINE E- LUDWIG

ISSUED BY
THE SMITHSONIAN INSTITUTION
WASHINGTON, D-C-, U-S-A-

SEPDEMBER 983

ECOLOGICAL PROBLEMS ASSOCIATED WITH DISRUPTION OF DUNE VEGETATION
DYNAMICS BY CASUARINA EQUISETIFOLIA L- AT SAND ISLAND,

MIDWAY ATOLL

1
By Steven I. Apfelbaum , James P. Ludwig and Catherine E. dedi

INTRODUCTION

Exotic plants and animals may be introduced in ecosystems because
of desirable qualities or by accident. Many introductions have caused
great harm because of unpleasant characteristics which are realized only
after introduction. lLIronwood (Casuarina equisetifolia L.) is one such
species. Introduced for shade and ornamental purposes in subtropical and
tropical areas, this adaptable and quick growing tree has caused ecological
changes which may limit its future introduction. Ironwood can be a
Pioneer species that colonizes nutrient depauperate soils, especially
nitrogen poor areas, because of its nitrogen fixing capability (Aldrich
and Blake, 1932). Equally important is its ability to reproduce by
several assexual modes in addition to sexual routes. These character-
istics make this species a persistent management problem. This paper
presents our observations of Ironwood ecology and this plant's relation-
ships with native vegetation, seabirds, and man on Midway Atoll.

The Casuarinaceae is a distinctive family of trees and shrubs from
dry or saline habitats of southeast Asia and the southwest Pacific.
Ironwood branches have a characteristic weeping habit with peculiar
jointed leaves in a whorled branching pattern. Male and female flowers
are separate with the latter borne in dense spheroid heads near branch
ends. Leaf size is reduced with photosynthetic tissues and stomatal
openings found in stem interrib spaces, probably an adaptation to prevent
dessication. Surprisingly, little ecological, life history, or manage-
information is available on the Casuarinaceae.

THE STUDY AREA
Midway Atoll, located 2100km northwest of Honolulu, Hawaii, has been

occupied by man since the early 1800's. Midway was a major link in the
first trans-Pacific telegraphic cable system and has been a major U.S.

Depicted Ecological Services, P.O. Box 2021, Roosevelt, Utah 84066

“Hasigsieall Research Services, Inc., 312 W. Genesee Street, Iron River,
Michigan 49935

Manuscript received Dec. 1980--Eds.

naval facility since 1939. Two islands are found in the southeastern
area of the enclosed atoll lagoon. Sand, the larger island (Figure 1)
is 2.9km by 1.9km, with an area of 482 hectares. It has a maximum
elevation of 13.1lm. Eastern Island, 1.5km east of Sand is 320 hectares
with an elevation of 10.4m. Before human settlement, Sand Island was a
sandy expanse with a naturally depauperate vegetation. Shorelines and
dunes were stabilized by the dune binding complex including Scaevola
taccada and the prostrate herb, Ipomoea indica. Shifting sands were
normal, especially in central areas of the islands. Since settlement,
beach erosion on Sand Island has been an expensive problem which com-
plicates maintenance of shorelines, buildings, docking facilities and
other military structures. The climate is subtropical with an average
annual precipitation of 10lcm. Rainfall occurs an average 12 days a
month; December through February are the wettest months; March is the
driest. Northeastern trades prevail from March through October with
stronger westerlies from November to February. Highest mean monthly
temperatures approach 30° C. while May, June and November temperatures
range from 21-27 C. (Woodward, 1972). Although no data are available
on evapotranspiration rates, these are certainly highest during warmest
and windiest periods.

In 1903, the telegraph company planted Ironwood in the northern
windward areas of Sand Island. Ironwood now covers much of the unpaved
surface of the island, where it often forms a thick canopy or tangle of
saplings. Many other trees and shrubs have been introduced, but, by
far, Ironwood dominates the island ecosystem. Some Ironwood individuals
exceed a 25m height and 1m diameter at breast height (d.b.h.). Along
the northeast shore, this tree forms a thick canopy and litter that may
reduce understory vegetation. Ironwood selects against birds of open
habitats and favors those species associated with forested areas.

ACKNOWLEDGEMENTS

We thank numerous Fish and Wildlife Service personnel for providing
help in arranging our research endeavors in Midway. Special thanks to
Dr. Derral Herbst, Mr. Brent Giezentanner and Dr. William DeMichele for
their help in various aspects of manuscript preparation and data col-
lection. U.S. Navy personnel, especially CWO Donald Richardson, provided
much field support.

METHODS AND MATERIALS

Vegetation studies were conducted February 15-24, 1979 in Sand
Island. Casual observations of Eastern Island vegetation were made
during this same time. Beach vegetation dynamics were investigated along
representative beach exposures on Sand Island. We measured intercepts
for each plant species along 30, 2x25m transects that originated at the
seaward foot of the foredune, and went inland. Using this method, rela-
tive cover for each plant species was summarized over the north, west
and south beach areas of the island. Ten transects were established in

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each of these exposures. Fruit and seed productivity estimates were

made for Ironwood. All newly fallen cones located in four 0.25m™ quad-
rats were used to estimate and measure fruit production. Seed production
estimates were made by counting the number of pairs of woody bracts
opened in the cones that had dropped seed.

A plant species list was generated for Sand Island (Appendix).
Species of noteworthy status, those providing difficulty in identifica-
tion, or of uncertain status, were collected and are maintained at the
University of Illinois Herbarium, Urbana. Other species were listed
as observed.

RESULTS

Ironwood has wind disseminated samaroid seeds approximating a
measurement of 5mm x 2.5mm. Small Ironwoods (having a d.b.h. of 5cm
or less and less than 2m in height) produced cones and seeds of identical
size as larger older trees. Comparative germination and viability tests
were not undertaken. However, Aldrich and Blake (1932) reported an
average germination rate of 84% (n=437) for Ironwood seeds washed in
mercuric chloride and water. They found seedling mortality to be "low".
Over a 15 month period, their control plants attained a height of 40cm
compared to test plants innoculated with extracts from root nodules on
wild Ironwood which grew to 140cm heights.

Ironwood seedling densities along Sand Island runways suggest high
germination and seedling success rates. Ironwood seedling density in
one location exceeded 75 seedlings per square meter. Fruit production
estimates averaged 30 cones/m beneath the test trees (Table 1) and
ranged from 21-38 cones. Seed production varied from 3,696 to 5,168
(x=4,602) seeds per meter square. Total estimated seed production for
the test trees ranged from 109,880 to 258,400 and averaged 184,000 seeds
per tree which assumes a single seed crop per year.

TRANSECT RESULTS

Frequency distribution for vegetation as a function of distance
from the foredune is plotted in Figures 2A-2F. Ironwood and Scaevola
were the most frequently encountered species in all locations. Scaevola
was encountered more frequently near the foredune and declined inland on
the north and south beaches (Figures 2A and 2C). As Scaevola declined,
Ironwood became more abundant; Scaevola was almost displaced by Lronwood
in the first 25m inland from the foredune, especially in the north and
west beach study areas. Data from the west beach (Figure 2B) suggest
Ironwood invasion to be far more complete than along other beaches.
Ironwood dominated Scaevola from the foredune inland to 18m where
Scaevola became slightly more abundant, but only as a decadent under-
story element. Scaevola had a relatively uniform distribution inland
from the foredune for 25m along the west beach. Most plants except
Tournefortia occurred behind the foredunal Scaevola. There Scaevola

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Figure 2.
Plant Frequency vs. Distance Inland from Foredune Origin:

1O- A:
:) Transects 1-10 Ku-22 Sta
Og NORTH BEACH fo) Casuarina

0 2 4 6 S 10.212: 14.16) 18: 7205) 220524 fee

Foredune Distance (m)
10_B. Transects 11-20
9 WEST BEACH
8
7
6
5
4
3
2
1

0 2 4 6 8 10 12 14 16 18 20 22° 24 26

Cc. Transects 21-30
SOUTH BEACH

—_

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0 2 4 6 8 10 12 -14 16 18 =20%) 2255245026

7
Figure 2. (continued)
D Plant Frequency vs. Distance Inland from Foredune Origin:
10_

Transects 1-10

NORTH BEACH
x Stenotaphrum
O---- Euphorbia

Absolute Frequency
=aNWAUDNOWO

0 2 4 6 8 10 12 14 16 18 20 22 24 26

Foredune Distance (m)
10._ E.
9 Transects 11-20
8 WEST BEACH
7 ° Cynodon
6 O---= Tournefortia
5 KX seece Verbesina
4
3
2
1

0 2 4 6 8 10 12 14 16 18 20 22 24 26

10 _ F.
9 Transects 21-30
8 SOUTH BEACH
7 O----Lobularia
{0} Tournefortia
6 XK cecence Verbesina
5
4
3
2
1 plaieivevets

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0 2 4 6 8 10 12 14 16 18 20 22 24 26

distribution trends hold in the north and south beaches as well, although
Bermuda Grass (Cynodon dactylon) also occurred in the foredunal areas.
Along the west and south beaches, Tournefortia occurred infrequently from
the foredune to at least 20m inland. Along the west and north beaches
Scaevola was reduced to an understory layer beneath a closed Ironwood
canopy.

Scaevola and Ironwood each accounted for nearly 33% of all species
intercepted in the transects. Thus, over 60% of all the plant intercepts
along the transects resulted from these species. The cover importance
of Scaevola and bare ground dropped to 24% each, while Ironwood and
Bermuda Grass values were highest in the west beach. Along the south
beach, Ironwood was less abundant than Scaevola or bare ground and
Tournefortia was nearly as important as Ironwood.

Most of the 123 plant species we encountered on Sand Island were
exotics. Of these, few were found in the beach areas. Most occurred
only where organic soils had been imported or developed near dwellings,
or in the shade of larger Casuarina (Neff and DuMont, 1955; Lamoureux,
1961). Ironwood seedlings were present throughout, but only in associ-
ation with Scaevola and Tournefortia when present in the foredunes.
Seedlings were numerous behind the foredunes along the north beach, but
were not found independent of these dune binding shrubs except in areas
shaded during most of the day.

Black rat (Rattus rattus) damage to native shrubs was not quantified.
However, we found severe damage to Scaevola especially inland of the
foredune where larger Ironwood were present as canopy elements. Rat
damage was found only on Scaevola. The rodents chewed succulent apical
and lateral buds which reduced lateral and vertical growth potentials of
Scaevola. In some places, particularly along the west beach, damage
was so severe that we believe Scaevola is certain to be eliminated.

Along the vegetation surveys, Laysan Albatross nest densities
(Table 2) varied from 8 to 89 nests per acre. Black-footed Albatross
nested in the west and south beaches but no nests were located along
the north beach transects. The Albatross species seldom nested together.
Black-foots associated with openings between Scaevola clones; Laysans
nested within thinned Scaevola clones under Ironwood canopies, or where
Ironwood seedlings and saplings grew into a thick bush-like form.

DISCUSSION

The foredune begins 50-75m from the high tide along the north
beach, which was actively building. This beach had dense rounded clones
of Scaevola 0.5-1.8m in height, especially between the cross runway and
the enlisted men's beach. Immediately behind the foredune were large
Ironwood that shaded the foredune at various times of the day and season.
Ironwood seedlings were scattered throughout the Scaevola. However, few
seedlings were present under the larger Ironwood. Inland of the Ironwood
were numerous cultivated plants, especially in yards of abandoned houses.

Table 2. Breeding bird nest densities for nests Encountered in 2x25m
Vegetation Transects

# of Nests by Species Encountered

North Beach Black-footed Laysan
Transects 1-10 Albatross Albatross

1 1

2. 1

3 il

4 1

5 2

6 1

7 2

10 D
Nesting density per 500m 0 11
Nesting density per acre 89
Nesting density per hectare 0 220
West Beach
Transects 11-20

11 1

16 4

18 2

19 2

20 4
Nesting density per 500m 8 5
Nesting density per acre 65 40
Nesting density per hectare 160 100

South Beach
Transects 21-30

21 1

22 1 1

28 1

29 2

30
Nesting density per 500m 5 1
Nesting density per acre 40 8

Nesting density per hectare 100 20

These included the exotics Chinese Banyan (Ficus microcarpa), Poinsettia
(Euphorbia cyathophora), and Bermuda Grass.

The west beach was severely eroded even though rip-rap had been
previously installed for prevention. In winter, northwest storms subject
this beach to erosive winds and waves that develop over the 9.6km (6m)
distance to the fringing reef. The tide-line to foredune distance
varied from 0-25m. Fallen Ironwood showed the original shore had been
undermined and the beach zone lost. Based on comparisons with the
north and south beaches (Figures 2A and 2C), 12-18m of beach and foredune
have been removed by erosion along this beach. Scaevola is overtopped
by Ironwood along this beach. Surviving Scaevola was in very poor con-
dition with severe dieback and rat damage evident. Beneath high density
Ironwood stands, herbaceous ground cover was absent. In some areas,
Scaevola had recently died back and few stems survived. Most stems
were leafless and assumed a shriveled-desiccated appearance. Young
Crown-beard (Verbesina enceloides) plants invaded dead and dying
Scaevola clones. We have no information on the persistence of this
species under the Ironwood. Since Crown-beard did not occur in exposed
foredunes, it may require ameliorated conditions associated with the
larger Ironwoods to establish in the dunes.

The west point of Sand Island just west of the paved end of the main
runway was dominated by large Scaevola that showed little rat damage.
In this area, no Ironwood seedlings were found seaward of a few esta-
blished Ironwood trees 5-10 years of age located 80m inland from the
tide line.

Between the south beach and dump, Scaevola declined and was largely
restricted to an undercut sand ridge with a relief of 3-5m from the
level of Waldron Blvd. to the ocean. Erosion abatement structures,
including wood and steel pilings, and cement breakwalls, have been
utilized here. However, most were washed out. Present between the
ridge and boulevard were Ironwood, sea grape (Coccoloba uvifera),
Scaevola and Tournefortia. Large Tournefortia shrubs up to 5m tall
were present east of the naval facility buildings on the ridge. Ironwood
seedlings grew in the Scaevola, especially with older Ironwood along the
crest of the ridge. To the east, the ridge flattened; Scaevola and
Tournefortia became less abundant. In this area, scattered Ironwoods
were present in and around several dune blowouts. Dense colonies of
Black-footed Albatross nested in these blowouts and associated sparsely
vegetated areas. However, little nesting occurred on the beach below
blowouts. Sweet Alyssum (Lobularia maritima) was the most common ground
cover species in and around blowouts. This plant was especially lush
where Albatross defecated, often growing in circular patterns around
their nests. We found less rat damage on Scaevola here than along either
the west or north beaches.

Beach vegetation dynamics on Sand Island result from interactions
between native plants, rats, the complement of introduced species, and
continuing disturbance by mankind. Native dune shrubs tolerate high
sand temperatures, salt spray and prevailing windy conditions. They

grow well under these conditions for there is little competition, and
unlike most introductions, they are able to compensate for sand burial
by differential growth and adaptive growth forms fitted to wind, sand
scour and dessication stresses.

Adaptations include waxy, succulent and pubescent-reflective
foliage. Aerodynamic spheroid to prostrate growth forms such as thick,
hemispherical shape of the Scaevola and trailing Ipomoea are important
adaptive features. Though adjusted to the environmental stresses of
beaches and dunes, these plants seem to have a limited adaptive flexi-
bility. Apparently, slight environmental changes can have serious impacts
on these plants, probably due to their extreme specialization to a
severe environment and relatively slow growth rates. Rat damage and
Ironwood intrusion, singly or synergistically, stress Scaevola, the key
native species. Scaevola is undoubtedly shade intolerant, growing best
in exposed beach sites, with sparse Tournefortia or other shrubs. The
establishment and growth of Ironwood in Scaevola clones may eliminate
this plant and the entire dune-shrub complex.

Micro-habitat changes that occur with Ironwood establishment and
growth among dune binding shrubs need investigation. Factors affecting
Scaevola may include increased shading, relative humidity, and physical
damage effects from branch and fruit fall from Ironwood, allelopathic
effects and associated alterations to hydrology and nutrient avail-
abilities may also occur. Scaevola germination and seedling establish-
ment may be hampered by thick and usually dry Casuarina litter. When
these factors are coupled with differential rat feeding pressures on
Scaevola this becomes a rather complicated problem for controlled
investigations.

Scaevola clones are aerodynamically suited to tolerate high winds,
sand scour and evaporative stresses. Ironwood was growing only in
Scaevola clones when in the beach areas which suggests that establishment
is dependent on an altered micro-climate offered by Scaevola clones.
Following establishment in a clone, Ironwood seedlings apparently send
long tap roots to ground water sources and rapid growth occurs. Lighter
red colored infrared tones on photos (Ludwig, et. al., 1979) suggest
these Ironwoods are less productive and more water stressed than Lron-
woods occurring more inland. However, Ironwood's colonization in
Scaevola occurs rapidly and is quickly followed by the establishment of
other Ironwood seedlings. This invasion pattern may explain the even
size (and possibly age) stands of Ironwood forming bands parallel to the
beach, especially along the west beach.

It is plausible that Scaevola, Ipomoea and other native plants
could be eliminated from Midway. With high seed set, apparent fast
growth and invasion rates, Ironwood is a major threat to the remaining
Mative plants of Midway. If Ironwood invades the beach zones, severe
erosion is likely to occur. JLronwood lacks the growth form and physiology
to effectively stabilize the beach areas. Severe erosion problems already
occur on the east shore of Eastern Island. Erosion control methods and
strategies deserve careful attention at Midway. Rip-rap apparently

functions as short-term control of a long-term erosion problem. This
method is less effective than natural vegetation erosion control,
especially against aeolian sand movements. Native dune binding shrub
management schemes, including means to control Ironwood would be
especially helpful for long-term erosion control; control of these
exotics may also cost less than structural alternatives such as pilings
and rip-rap. A well thought-out control plan can also benefit nesting
seabirds.

Changes in bird populations that occur with Ironwood establishment
are important considerations. Although Fairy and Noddy Terns, and
Laysan Albatross benefit from increased nesting habitat offered by
Ironwood, species such as the Red-footed Booby, Frigate Bird, and Black—
footed Albatross which use Scaevola and open areas for nesting seem
certain to suffer habitat losses.

Comprehensive studies on the management and control of Ironwood
should be initiated. Surprisingly, little information is available on
managing this species. It is clear that certain areas on Midway are
being damaged for continued Navy use and altered for other uses. The
cross runway is being invaded rapidly by Ironwood. The runway aprons
are almost completely invaded and root-heaving of the pavement by
Ironwood will probably destroy the runway in the 1980's. Similar
problems are far more advanced on the Eastern Island runways. Safe and
effective control methods for Ironwood are not known. However, any
chosen method should be amenable to continued human and seabird use.
This will require holistic ecosystem management.

REFERENCES CITED

Aldrich, R.N. and M.A. Blacke, 1932. On the Fixation of Atmospheric
Nitrogen by Bacteria Living Symbiotically in Root Nodules of
Casuarina equisetifolia. Oxford University Press. 20pp.

Lamoureux, Charles H., December 31, 1961. Botanical Observations
on Leeward Hawaiian ATolls. Atoll Research Bulletin 79:1-10.

Ludwig, James P., Catherine E. Ludwig and Steven I. Apfelbaum, 1979.
Observations on Status and Interactions of the Avifauna and Plants
of Midway Atoll, Leeward Hawaiian Islands, Between February 1-24,
1979. Ecological Research Services, Inc. Unpublished Report
(includes infrared photographs of vegetation).

Neff, J.A. and P.A. DuMont, August 15, 1955. A Partial List of the
Plants of Midway Islands. Atoll Research Bulletin 45:1-11.

Woodward, Paul W. 1972. The Natural History of Kure Atoll, North-
western Hawaiian Islands. Atoll Research Bulletin #164. 318pp.

APPENDIX

LIST OF PLANTS ON MIDWAY ATOLL, HAWAII
February 15-24, 1979

OBSERVED VOUCHF.RED
ACANTHACEAE
Asystasia gangetica
(L.) T. Anders. Asystasia
Odontonema strictum
(Nees) Kuntze
AGAVACEAE
Agave sp. Century Plant xX
Cordyline sp. Colored ti Xx
Dracaena sp. Dracaena xX
Sansevieria sp. Bowstring hemp
AMARYLLIDACEAE
Crinum asiaticum L. Spider lily
ANACARDIACEAE
Mangifera indica L. Mango xX
APOCYNACEAE
Carissa macrocarpa
(Eck). DG. Natal plum xX
Catharanthus roseus
(L.) G. Don Madagascar periwinkle xX
Nerium oleander L. Oleander
Plumeria sp. Plumeria; frangipani xX
Thevetia peruviana
(Pers.) K. Schum Yellow oleander X
ARACEAE
Alocasia cucullata
(Lour.) G. Don Chinese taro xX
Anthurium andraeanum
Lind. Anthurium xX
Colocasia esculenta
(L.) Schott Taro xX
Dieffenbachia sp. Dumb cane xX
Monstera deliciosa
Liebmn. Monstera
Rhaphidophora aurea Birdsey Pothos;
(Sinden Andre) Taro vine
Syngonium podophyllum (may be S. angustatum)
Schott
Xanthosoma sp. Elephant ear; Ape xX

ARALIACEAE
Schefflera actinophylla
(Endl.) Harms

ARAUCARLIACHEAE
Araucaria heterophylla
(Salisb.) Franco

BORAGINACEAE
Tournefortia argentea L.f.

(Messerschmidia argentea

(L.f.) Johnst.)

CANNACEAE
Canna indica L.

CARICACEAE
Carica papaya L.

CARYOPHYLLACEAE
Cerastium vulgatum L.
Spergularia marina

(L.) Griseb
Stellaria media
(L.) Cyrillo

CASUARINACEAE
Caruarina equisetifolia L.

CHENOPODIACEAE
Chenopodium murale L.

COMBRETACEAE
Terminalia catappa L.

COMMELINACEAE
Commelina sp.
Rhoeo spathacea
(Sw.) Stearn
Zebrina pendula Schnizl.

COMPOSITAE

Bidens alba L.

B. pilosa L.

Conyza bonariensis
(L.) Cronq.

Gnaphalium sandwicensium
Gaud.

Pluchea nymphytifolia
(Mill.) Gillis

Sonchus oleraceus L.

Verbesina enceloides
(Can.) Gray

OBSERVED
Octopus tree X
Norfolk Island pine X
Tree heloptrope X
Canna Xx
Papaya xX

Larger mouseear chickweek
Saltmarsh sand spurry

Common chickweed

Ironwood

Nettle-leaved goosefoot

Tropical almond X
Day flower X
Rhoeo : x
Wandering Jew X
Spanish needle xX
Horseweed
‘Ena ‘ena
Fleabane

Sow thistle

Golden crown beard

VOUCHERED

OBSERVED VOUCHERED

CONVOLVULACEAE
Ipomoea batatas (L.) Poir. Sweet Potato xX
I. indica (Burm.) Merr. Morning glory x
I. pes-caprae subsp. Beach morning glory
brasiliensis (L.) van Ooststr. X
Ipomoea sp. Morning glory X
CRASSULACEAE
Kalanchoe pinnata
(Lan.) Pers. Air plant x
CRUCIFERAE
Brassica nigra (L.) Koch Black mustard Ki
Capsella bursa-pastoris
(L.) Medik Shephard's purse x
Coronopus didymus
GE.) J. ES Smith Swinecress x
Lepidium densiflorum
Schrad. Xx
Lobularia maritima
(L.) Desv. Sweet alyssum x
CUPRESSACEAE
Cupressus sp. Cypress xX
CY CADACEAE
Cycas circinalis L. Cycad xX
CYPERACEAE
Cyperus alternifolius L. Umbrella plant xX
C. papyrus L. Papyrus ».4
C. rotundus L. Nut grass X
Fimbristylis pycnocephala
Hbd. X
EUPHORBIACEAE
Euphorbia cyathophora xX
GERANIACEAE
Pelargonium sp. Geranium xX
GOODENIACEAE
Scaevola taccada (Gaertn.) Naupaka X

Roxb. (S. frutescens
auct. nom. (Mille.) Krause)

GRAMINEAE
Bromus catharticus Vahl xX
Cenchrus echinatus L. Sand bur X
(C. hillebrandianus Hitchc.)
Chloris inflata Link Swollen finger grass xX
Cynodon dactylon (L.) Bermuda grass xX

Pers.

OBSERVED VOUCHERED
GRAMINEAE
Digitaria sanguinalis Crab grass X
(L.) Scop. var. ciliaris
(Retz.) Parl.
Eleusine indica

(L.) Gaertn. Goose grass xX
Eragrostis tenella

(L.) Beauv. Love grass xX
E. variabilis (Gaud.) Emoloa X
Lepturus repens

(Forster) R. Br. var. subulatus Fosb. X
Poa annua L. Annual blue grass X
Tricholaena rosea Nees Natal redtop xX
Setaria verticillata (L.)

Beauv. Bristly foxtail grass X
Sporobolus africanus African Dropseed X

Poir.) Robyns et Tournay
Stenotaphrum secundatum Buffalo grass Xx

(Walt.) O. Ktze.

LABIATAE
Coleus scutellarioides
(L.) Benth. Coleus xX
LILIACEAE
Aloe sp. Aloe X
Asparagus setaceus
(Kunth) Jessop Asparagus fern x
MORACEAE
Ficus benghalensis L. Banyan X
F. elastica Hornem. Rubber plant Xx
F. microcarpa L.f. Chinese banyan X
MALVACEAE
Abutilon grandifolium
(Willd.) Sweet Hairy abutilon xX
Hibiscus sp. Hibiscus X
Malva parviflora L. Little mallow X
Malvastrum coromandelianum
(L.) Garcke False Mallow xX
Malvaviscus arboreus Cav. Turks cap xX
NYCTAGINACEAE
Boerhavia repens L. Alena X
Bougainvillea sp. Bougainvillea xX
ORCHIDACEAE
Unidentified orchids X

Vanda sp. X

OBSERVED VOUCHERED

OXALIDACEAE
Oxalis corniculata L. Lady's sorrel x
O. martinana Zucc. Pink wood sorrel xX
PALMAE
Cocos nucifera L. Coconut xX
Phoenix sp. Date Palm xX
Pritchardia sp. Fan Palm xX
Roystonea sp. Cabbage and royal xX
PANDANACEAE
Pandanus sp. Screwpine; Hala xX
PLANTAGINACEAE
Plantago lanceolata L. Narrow leaved plantain xX
Ps major Iie Broad leaved plantain xX
POLY GONACEAE
Coccoloba uvifera L. Sea grape Xx
POLYPODIACEAE
Microsorium scolopendria
(Burm.) Copel. Laua'e os
Nephrolepis hirsutula
(Forst.) Presl. Sword fern xX
PORTULACACEAE
Portulaca oleracea L. Purslane xX
PRIMULACEAE
Anagallis arvensis L. Scarlet pimpernel xX
ROSACEAE
Rosa sp. Rose X
RUBIACEAE
Gardenia sp. Gardenia X
RUTACEAE
Glerus (spc Citrus xX
Murraya paniculata
G:) Jack Mock orange xX
SOLANACEAE
Capsicum annuum L. Red papper xX
Solanum nigrum L. Nightshade xX
UMBELLIFERAE

Apium tenuifolium
(Moench) Hegi Fir-leaved celery xX

OBSERVED VOUCHERED

URTICACEAE
Pilea microphylla (L.) Artillery plant;
Liebm. Rockweed xX
VERBENACEAE
Lantana camara L. Lantana x
Vitex trifolia L. Polinalina xX
ZINGLBERACEAE

Alpinia zerumbet (Pers.)
Burtt & R.M. Sm. (A.

speciosa K. Schum.) Shell ginger xX
Hedychium gardnerianum
Lindl. Kahili ginger xX
ZY GOPHY LLACEAE
Tribulus cistoides L. Puncture vine xX

OUT OF ALPHABETICAL ORDER:

LEGUMINOSAE

Albizzia lebbeck

(L.). Benth. Woman's tongue xX
Crotalaria incana L. Fuzzy rattle-pod xX
Delonix regia (Bojer) Raf. Royal poinciana xX
Desmanthus virgatus

(L.) Willd. Slender mimosa xX
Erythrina variegata var.

orientalis (L.) Merr Tiger's claw xX
Leucaena leucocephala

(Lam.) deWit Koa haole Xx
Medicago lupulina L. Hop clover xX
Samanea saman (Jacq.)

Merr. Monkeypod xX

SUBTOTALS : 54 69

TOTAL: 123

"ii

ATOLL RESEARCH BULLETIN
No- 262

THE FLORA AND VEGETATION OF SWAINS ISLAND

W. A-WHISTLER

ISSUED BY
THE SMITHSONIAN INSTITUTION
WASHINGTON, D- C-, U-S-A.

SEPTEMBER 1983

THE FLORA AND VEGETATION OF SWAINS ISLAND

by W.A. Whistler+

INTRODUCTION

Swains Island is an isolated atoll lying about 270 km north of
Samoa. Although geographically and floristically a part of the Tokelau
Islands 160 km to the northwest, it belongs politically to the Territory
of American Samoa. The island lies at a latitude of 11°03' S and a
longitude of 171°03' W. It has an area of 210 ha and a maximum elevation
of less than 6 m (Fig. 1).

The island is a ring-shaped atoll with a large, completely enclosed,
brackish water lagoon in the center (Fig. 2). In prehistoric. times the
lagoon was connected to the sea, but it is now completely landlocked. It
is shallow, but in spots reaches a maximum depth of 15 m. The water of
the lagoon is not potable, but is used for bathing and washing clothes.
Drinking water is obtained from a well, and from water catchment. The
rainfall on Swains Island is probably about 250 cm/year, since the
Tokelau Islands to the northwest have an average annual rainfall of over
250 cm (Parham, 1971).

Although the lagoon is nearly devoid of fish life, it is rich in
algae; one particular blue-green alga species (or mixture of species)
forms conspicuous, irregular chunks which make the shallow lagoon water
appear like a thick vegetable soup (Fig. 3). Buried deposits of a white
bivalve shell are found in the lagoon, but this mollusc species apparently
disappeared after the lagoon became landlocked. The pretty shells are
used by the Swains islanders to make unique leis.

Landing on Swains Island is made on the west side at Taulaga, the
only village on the island. Besides a small number of thatched, Samoan-
style huts ("fale"), Taulaga has a small white church and a large, barn-
like copra shed. Leading from the copra shed to the nearby beach are
old railway tracks which were once used to transport copra from the shed
to the beach for transfer to cargo vessels. Nearby is a large cleared
area that may one day be made into an airport runway to link Swains
Island by air to Tutuila, the main island of American Samoa. At the
present time supplies are brought in by boat from Tutuila several times
a year.

East of Taulaga, one third of the way around Swains along the
jeep road that circles the palm-covered island, is Etena (=Eden), the
former residence of the Jennings family, the owners of the island. The
imposing colonial-style house now stands abandoned in a state of disre-

c Department of Botany,. University of Hawaii, Honolulu, Hawaii. 96822

Manuscript received January 1980--Eds.

pair. Nearby are several well-kept graves, a final resting place for
some of the original settlers of the island.

The Swains islanders are a mixture of Tokelauans and Samoans,
mostly the former, with a bit of American and Portuguese heritage as
well. At the time of the author's visit, the population was less than
fifty. The language usually spoken is Tokelauan, but most of the
islanders are also conversant in Samoan and some in English as well.
The original Tokelauan name of the island is "Olosega", but this name
is no longer used. The name has led to some confusion, since there is
another island with the same name in the nearby Manu'a Islands of
American Samoa.

The original inhabitants of Swains Island were Tokelauan, but when
it was "discovered" by the Western world, it was uninhabited. Its
discovery is erroneously attributed to Quiros in 1606, but the island
discovered by this Spanish explorer is apparently Manihiki in the
Northern Cooks. The credit for the discovery goes to an American whaling
captain named W.C. Swain in or around 1839. It was visited by the U.S.S.
Peacock of the United States Exploring Expedition in 1840. Later, title
to the island was obtained by Eli Jennings, an American living on Upolu
(now a part of Western Samoa). With his Samoan wife, Malia, and his
family, he settled on the island in 1856, and the ownership of the island
has remained in the Jennings family ever since. The current head of the
family is Wallace Jennings who resides on the island.

BOTANICAL HISTORY

The first botanical information about Swains Island was gathered by
the U.S. Exploring Expedition during the aforementioned visit of the
U.S.S. Peacock in 1840. Although plant specimens were collected, they,
along with specimens from the Tokelau Islands, were subsequently lost.
Pickering (1876) stated, "Lists of plants growing up on them were com-
municated to me by Mr. Rich; after the loss of his specimens by ship-
wreck." Pickering's list of Swains Island plants included twelve spe-
cies--Hedyotis romanzoffiensis ("'Petesia"), Guettarda speciosa, Cordia
subcordata, Messerschmidia argentea, Boerhavia tetrandra, Procris
pedunculata, Pandanus tectorius, Cocos nucifera, Christella dentata
("Aspidium"), Asplenium nidus, Microsorium scolopendria ("Polypodium") ,

and Psilotum sp.

The next collector to visit Swains was apparently J. Lister in 1891.
No listing of his collections were published, but they are deposited at
Kew and Cambridge University. One of his specimens--Hedyotis
romanzoffiensis--was cited by Fosberg in his revision of the genus
(1943). Other unpublished collections were made between 1929 and 1939
by P. Diefenderfer, E. Bryan, and L. Schultz. Diefenderfer, an anthro-
pologist working for the Department of Education of American Samoa,
collected about 14 species during trips to Swains in 1929 and 1930, but
no field notes are known to exist. Bryan collected on Swains during

visits in 1935 and 1938. Approximately 82 specimens were collected
(mos. 912-55, 1345-74, and some unnumbered ones), the data for which
is found in field books stored at the Bishop Museum in Honolulu. The
specimens of Diefenderfer and Bryan are also deposited at the Bishop
Museum. Schultz, an ichthyologist, visited Swains in 1939 and made a
small collection of about 10 specimens, and these are deposited at the
Smithsonian Institution.

In 1966-67 R.B. Clapp, an ornithologist, visited Swains a number
of times and recorded the bird life of the island (Clapp, 1968). Al-
though he did not directly discuss the vegetation or flora of the
island, he did mention the presence of Cocos, Pisonia, Pandanus,
Messerschmidia, and Seaevola. He apparently did not collect any plant
specimens.

In 1971 B. Parham published a study of the vegetation of the nearby
Tokelau Islands, based on his own work and the work of others. It
includes a checklist of the flora of Nukuono from specimens collected
by K. Wodzicki in 1966-68. The flora of the Tokelau Islands is very
similar to that of Swains, but based on Parham's checklist of the
flora of the largest of the three atolls, it may be smaller than that
of Swains. Parham's paper included the Tokelauan names for the plants;
these names were very useful when questioning the Swains islanders about
their island's plants.

The first and only comprehensive collection of the flora of Swains
was made by the author from the 18th to the 21st of May 1976. The four
day visit was part of an inventory of the flora and fauna being carried
out for the USFWS (1978), and this report, which is as yet unpublished, con-
tains much biological information about Swains. Up until that time,
only 56 species of vascular plants had been collected or recorded from
Swains, but now this number is 95. Only three of the previously reported
species were not found during the author's visit--Solanum nigrum,

Hedyotis romanzoffiensis, and Annona muricata. Approximately 88 specimens
were collected during this visit (nos. W 3352A to W 3439), and these will
be deposited at the Smithsonian Institution and the Bishop Museum.

THE VEGETATION

The vegetation of Swains Island is greatly disturbed and nearly the
whole island is covered with coconut palms. It is doubtful if any of
the original forest vegetation remains. Due to the short duration of
the author's visit, no quantitative work could be done. However, based
on the observations made, the vegetation of Swains can be divided as
follows:

Native vegetation

Sand strand
Littoral shrubland

Littoral forest
Coastal marsh

Disturbed vegetation

Coconut plantation
Village land

Each of these types of vegetation is discussed below.
Sand strand

The sand strand or 'Pes-caprae'' formation as it is often called,
consists of a small band of herbaceous plants on the seaward margin of
the littoral forest (Fig. 4). This vegetation type is poorly developed
on Swains, particularly because the most characteristic plant--Ipomoea
pes-caprae--is absent. Another characteristic plant of the sand strand-—
Vigna marina--is apparently only a recent introduction and was found in
only one small patch at Taulaga.

The dominant species of the sand strand of Swains Island are
Lepturus repens, Fimbristylis cymosa, Boerhavia tetrandra, and
Triumfetta procumbens. The first two are common in scattered clumps
on the exposed sandy shore above the hightide mark, while the latter
two are in less exposed areas.

Littoral shrubland

The littoral shrubland is the shrub-dominated vegetation on the
seaward margin of the littoral forest. In Samoa, this vegetation is
dominated by Scaevola taccada, Wedelia biflora, Ficus scabra, and
Clerodendrum inerme (Whistler, 1980), but only the first of these
species is found on Swains.

In addition to the shrubland on the edge of the littoral forest,
northeast of Etena there is a large inland area of this vegetation
dominated by Scaevola taccada (Fig. 5). The reason for this patch of
shrubland in the midst of the coconut groves was not determined, but
it probably resulted from some disturbance by the islanders.

Other less common plants found in the littoral shrubland are
Pemphis acidula, Messerschmidia argentea, Ipomoea macrantha, Cassytha
filiformis, and Achyranthes velutina.

Littoral forest

Originally, most of the island was covered by littoral forest.
That which remains today is found along the shores and in scattered
patches in the coconut plantation (Figs. 6 and 7). Probably all of
the existing littoral forest is secondary and has developed when parts
of the coconut plantation were neglected and coconut palms were grad-
ually replaced by littoral forest species.

‘Si

The dominant littoral tree on Swains is Hernandia sonora, and there
are some small patches of nearly pure Hernandia forest away from the
immediate coast. The forest floor in these patches is very open, with
only scattered Bryophyllum pinnatum, Asplenium nidus, and Microsorium
scolopendria on the ground (Fig. 8). Other common littoral forest trees
are Pisonia grandis, Neisosperma oppositifolia, Pandanus tectorius,
Guettarda speciosa, and Messerschmidia argentea. The latter species is
limited to sunny areas, mostly on the forest margins.

Less common are Hibiscus tiliaceus, Cordia subcordata, Calophyllum
inophyllum, and Barringtonia asiatica. The latter species may have
been more common in the past, but only two individuals were seen during
the visit. Wallace Jennings reported that he had others cut down because
he doesn't like this tree, perhaps because of its potential use as a
fish poison. Epiphytes in the littoral forest are few, consisting only
of Procris pedunculata, Vittaria rigida, Psilotum nudum, and Psilotum
complanatum.

Coastal marsh

The herbaceous vegetation growing along the margins of the lagoon
ean be classed as a coastal marsh. Where disturbed, the vegetation is
dominated by Ludwigia octivalvis, Cyperus javanicus, and Paspalum
distichum.

On the north shore of the lagoon there is a small peninsula extending
out into the water (Fig. 2). It is covered by undisturbed coastal marsh
vegetation dominated by Eleocharis geniculata and Paspalum distichum,
with some scattered Pemphis acidula in higher, drier areas. This is
the first record of this species of Eleocharis in Samoa or Tokelau.
A specimen of this rush collected by E. Graeffe in 1870 was listed as
being collected in "Samoa", but this is probably a mistaken locality,
and it may have been collected in Fiji instead.

Similar coastal marsh vegetation in Samoa is dominated by Eleocharis
dulcis, Cyclosorus interruptus, and Acrostichum aureum, but none of these
species is found on Swains.

Coconut plantation

Most of Swains Island is covered with coconut plantation (Fig. 9).
The plantation is in a state of neglect, since copra is no longer exported.
Patches of littoral forest species are scattered throughout the coconut
palms, and it is apparent that if left undisturbed, most of the palms would
be eliminated by other more aggressive littoral forest species.

Underneath the coconut palms is a thick, almost impenetrable growth
of young coconut palms and the “bird's-nest fern", Asplenium nidus, which
exclude nearly all other species from becoming established.

Village land

The village land consists of areas cleared for houses, roads,
and for crops other than coconut. These disturbed areas are dominated
by introduced weedy species. The large grassy village green ("malae")
at Taulaga (Fig. 10) and grassy areas at Etena are dominated by grasses,
sedges, and other herbaceous weeds. The dominant weedy species are
Euphorbia hirta, Phyllanthus amarus, Sida rhombifolia, Portulaca oleracea,
Boerhavia tetrandra, Spermacoce assurgens, Physalis angulata,
Stachytarpheta urticaefolia, Cyperus kyllingia, Cyperus rotundus,
Fimbristylis dichotoma, Cenchrus echinatus, Chrysopogon aciculatus,
Axonopus compressus, Cynodon dactylon, Eleusine indica, Eragrostis
tenella, Lepturus repens, and Paspalum conjugatum. In wet areas,
Ludwigia octovalvis is the dominant weedy species.

The crops grown for food on Swains Island are Musa paradisiaca,
Ipomoea batatas, Carica papaya, Pandanus tectorius (a cultivar),
Mangifera indica, Citrus aurantium, Citrus medica, and Artocarpus
altilis. These grow around houses and on the edges of the village.

West of Taulaga, there is a swampy area where the large aroid Cyrtosperma
chamissonis is grown. Alocasia macrorrhiza and Colocasia esculenta are
also grown, but to a lesser extent.

In addition to the crop plants, some ornamentals are grown, but
except for some remnants at Etena, these are mostly in the vicinity
of houses at Taulaga.

THE FLORA

The following is an annotated checklist of the vascular flora of
Swains Island. The species are listed in alphabetical order by family
under Pteridophyta, Dicotyledonae, and Monocotyledonae. Following the
species name is the collection number of the author which is always
preceded by a "W'"', while those of the other collectors are preceded
by their names. The native names for the species, which are usually
the same as in Samoa or the Tokelau Islands, are also given.

Pteridophyta

ASPLENTIACEAE

Asplenium nidus L.

"Laumea", which is the Tokelauan name. In Samoa it is called
"laugapapa." The bird's-nest fern is very common as an epiphyte
or growing on the ground in the forest. The young stems are
cooked and eaten. W 3397, Bryan 919.

DAVALLIACEAE
Nephrolepis hirsutula (Forst.f.)Presl
A yery common fern of the forest and particularly in sunny disturbed
places. Parham lists the Tokelauan name as “laumailekimoa."
W 3399, Bryan 940, 941, 942, and 1352.
POLYPODIACEAE
Christella dentata (Forssk.)Brownsey & Jermy in Brit.
A large ground fern common in disturbed places. This was previously
referred to as Dryopteris nymphalis (Forst.f.)Copeland. W 3398,
Bryan 943.
Microsorium scolopendria (Burm.f.)Copeland

"Laumaile'", which is the Tokelauan name. In Samoa it is called
"Lau auta." A common epiphyte or ground fern of the forest. It
y

is also known as Polypodium scolopendria Burm. f. and Phymatodes
scolopendria(Burm.f.)Ching. W 3401, Bryan 913, 914, 915, 939, 1353,

& 1359.
PSITLOTACEAE
Psilotum complanatum Sw.

An epiphyte growing on the trunks of coconut palms. W 3433,
Bryan 1367.

Psilotum nudum (L.) Beauv.
"Moegaotekimoa" (bed of the rat), according to Mr. Jennings.
Parham lists the Tokelauan name as “faleotekimoa'" (house of the
rat). An epiphyte occasional on forest trees and coconut palms.
W 3359, Bryan 1366.
VITTARIACEAE

Vittaria rigida Kaulf. var. samoensis (Luerrs.)C.Chr.

A small unbranched epiphytic fern, occasional on forest trees.
W 3425 and W 3396.

Angiospermae
DICOTYLEDONAE

ACANTHACEAE

Hemigraphis alternata (Burm.f.) T. Anders.

"Suipi.'" Not seen, but reported by a reliable islander to be

growing there. A purple-leafed prostrate herb occasionally
cultivated in Samoa.

AMARANTHACEAE
Achyranthes velutina H. & A.

No name was given, but this is called "tamatama'! in Tokelau

(a closely related species, Achyranthes aspera, is called "lau
tamatama'' in Samoa), It was found in only one locality, on the
coast north of Taulaga. It was not previously recorded from
American Samoa. W 3420.

ANACARDIACEAE
Mangifera indica L.
"Mago.'' The mango was not seen, but it was reported by a reliable

islander to be growing in at least one locality.
ANNONACEAE
Annona muricata L.
"Sasalapa", according to Bryan. This is the same as the Samoan
name for the soursop. It is cultivated, or at least it was when
Bryan visited the island. Bryan 916.
APOCYNACEAE
Catharanthus roseus (L.)G. Don
A garden escape found around houses and grave sites. W 3374.
Neisosperma oppositifolia (Lam.)Fosb. & Sachet

"Pulu fao."' A small to medium-sized tree occasional in the forest.
In Samoa the name is "fao'', and "pulu" refers to the milky sap of
the tree. This species has not previously been recorded from
American Samoa. W 3424.

Plumeria rubra L.
"Pua.'' The frangipani tree is commonly cultivated around houses.
Both the red variety (var. rubra) and the white one (var. acuminata)
were seen, but only the later was collected. W 3388
ARALIACEAE
Polyscias guilfoylei (Bull.)L.H.Bailey

"Tagitagi.'' A cultivated shrub found at Etena. It is a common

hedge plant in Samoa. W 3391.

BORAGINACEAE
Cordia subcordata Lam.
"Tauanavye." A large tree scattered over the island, In Tokelau

it is called "kanaya.'' Qn Swains Island the wood is called
"taiuli" and is excellent for posts and carvings, since it is strong
and durable. W 3406, Bryan 920.

Messerschmidia argentea (L.£.)Johnst.
"Tausuni.'' The common "tree heliotrope"' is known as “tauhunu" tn
the Tokelau Islands, and is common along the shore and in sunny
disturbed areas. It is also commonly known as Tournefortia argentea
L.£., but is probably most correctly called Argusia argentea (L.f.
Heine. W 3392. our

CARICACEAE

Carica papaya L.

"“Esi."' The papaya is commonly cultivated and sometimes grows wild.
Two varieties occur on the island--one called simply “esi" and the
other “esi loa.'' The male flowered tree is called “esi tane."'
Seen, but not collected.

COMPOSTTAE

Adenostemma lanceolatum Miq.
A weed with white flowers, found in wet, shady places, The same
or a similar species is found as a trailside weed in mountain
ferests of Samoa. W 3357, Bryan 931.

Synedrella nodiflora (L.)Gaertn.
A yellow-flowered weed common in disturbed places. W 3437.

Vernonia cinerea (L.)Less.

A lavender-flowered weed occasional in disturbed places, W 3380,
Schultz 11, Bryan 931A and 1371.

CONVOLVULACEAE

Ipomoea batatas (L.) Lam.

"tUmala.'' The sweet potato is occasionally cultivated on the
island, W 3418,

Ipomoea macrantha R. & S.
"Fue itula."" A white flowered morning-glory vine common in the
littoral forest. The word "itula" means hour, perhaps referring
to the short time while the flower is open in the morning before
wilting. The name has not previously been recorded from the
Tokelau Islands or Samoa, so it is probably just a local name.
W 3393, Bryan 1374.

CRUCIFERAE

Nasturtium sarmentosum (Forst.f.)Schultz

A small weed of shady disturbed places such as in dirt roads and
trails. W 3378.

CRASSULACEAE

Bryophyllum pinnatum (Lam.)Kurz

"Pagi.'’ A common weed of disturbed places and naturalized in the
forest. Children call this plant "mimiti'(to suck), which refers
to their method of obtaining a sweet juice from the flower. It is
also known as Kalanchoe pinnata (Lam.)Pers. W 3410, Bryan 928 and
1360 , Diefenderfer 9, 15, and s.n.
EUPHORBIACEAE
Codiaeum variegatum (L.)Bl.

The croton is a common hedge plant in Samoa. At least two varieties
are found on Swains. W 3384 and 3430, Bryan 937 and 1357.

Euphorbia hirta L.

This spurge is common in disturbed gravel and grassy areas around
houses. W 3366, Bryan 1373.

Euphorbia prostrata Ait.

A small, prostrate weed found in the village in gravel and on
rock walls. W 3413.

Phyllanthus amarus Sch. & Thon.

A common weed of disturbed places. Elsewhere incorrectly referred
to as Phyllanthus niruri L. W 3402, Bryan 1372, Schultz 12.

GOODENLACEAE
Scaevola taccada (Gaertn,.) Roxb.

"To'ito'i.'' This shrub is common on the coast and in sunny

disturbed places inland. The name in Tokelau is "gahu." "To'ito'i"
is used on Swains, but this term apparently more correctly refers
to the pith of the stems. W 3389, Schultz 13, Diefenderfer s.n.

GUTTIFERAE

Calophyllum inophyllum L.

"Fetau."' This widespread Pacific tree is found scattered in the
forest, often reaching a very large size. In Tokelau it is called
“hetau." W 3407, Bryan 917 and 1354, and Schultz 5.

HERNANDLACEAE
Hernandia sonora L.
"Pula." This is the second most common tree on Swains Island

(second to Cocos). It is called "puka" or "pukavaka" in the
Tokelau Islands. W 3395, Bryan 926 and 1368, Diefenderfer s.n.

LABIATAE
Coleus scutellarioides (L.)Benth.
"Fateine."' Coleus is a cultivated shrub with showy leaves. The
Samoan name is "patiale", and since Coleus is not reported from
Tokelau, "fateine" may be a local name. W 3385, Bryan 936.
Ocimum sanctum L.
"Militini." The basil is a garden escape that is occasionally

found around dwellings, particularly at Etena. It is used to scent
coconut oil. W 3372, Bryan 1356.

LAURACEAE
Cassytha filiformis L.
"Fetai." This is a leafless parasitic vine common growing on

shrubs and small trees in disturbed areas and in coastal vegetation.
W 3367, Bryan 921 and 1345, Schultz 16.

LECYTHIDACEAE

Barringtonia asiatica (L.)Kurz

"Putu." A common coastal tree of the Pacific, but only two mature
trees were found during the visit. They may have previously been
more common, but Mr. Jennings reported he has had them cut down.
The Tokelauan name is “hutu". W 3423.

it,

LEGUMINOSAE
Adenanthera pavonina L.
"Lopa."" A tree cultivated for its edible seeds. Occasional in

village areas and along roads. W 3386.

Delonix regia (Bojer)Raf.
"Elefane.'' The poinsiana tree is found cultivated in several places
on the island. The name appears to be a local one. W 3383, Bryan
922 and 1358.

Vigna marina (Burm.)Merr.
A coastal vine widespread in the Pacific, but seen in only one

small patch near Taulaga. Mr. Jennings reported it was a very
recent arrival. W 3426.

LYTHRACEAE
Pemphis acidula J.R.& G.Forst.
“Gagie.'' A shrub growing on the shore and along the lagoon. It is

reported to be the hardest wood on Swains Island, and is used

to attach the canoe outrigger. It has not been previously reported
from American Samoa, and is rare in Western Samoa. W 3354,
Diefenderfer s.n.

MALVACEAE
Hibiscus rosa-sinensis L.
"TAute."" A cultivated shrub with showy red flowers, not seen, but

reported by a reliable islander to be growing on the island.
Hibiscus tiliaceus L.

"Fau.'' The beach hibiscus is scattered in disturbed areas on the
island. The Tokelauan name is "hau."'" W 3405, Bryan 933 and 1359.

Sida rhombifolia L.

"Mautofu."" A shrub with salmon-colored flowers,common as a weed in
disturbed areas. W 3365, Bryan 930 and 1370, Schultz 9.

MORACEAE
Artocarpus altilis (Park.)Fosb.

"'Ulu.' Several varieties of breadfruit are cultivated on Swains,
and some of the trees are over 50' high. Varietal names include

iL3)

“"mafala", ‘ulu Elise", and "puou", all of which are also known
in Samoa. W 3434.

Ficus tinctoria Forst.f.
"Mati." Not seen but reported by the islanders to be present.
The small orange fruits are eaten. This small tree is also found
in Samoa and the Tokelau Islands, and in both places it is also
called "mati."
NYCTAGINACEAE
Boerhavia tetrandra J.R.& G.Forst.
"Nuna."" A pink-flowered prostrate herb growing in disturbed
places on the island. It is a widespread littoral species in the
Pacific. W 3382.
Mirabilis jalapa L.
A shrub with white flowers, cultivated near Taulaga. W 3422.
Pisonia grandis R.Br.
"Pu'avai.'' A tree with sticky fruits, found in scattered patches
in the coconut-dominated secondary forest. The leaves are used
to feed pigs and the wood is used for posts. The Tokelauan name
is "pukavai" or "pukakakai."" W 3409.
ONAGRACEAE

Ludwigia octovalvis (Jacq.)Raven

An erect yellow-flowered herb, common as a weed in wet places.
W 3415, Bryan 927, Diefenderfer 10.

POLYGALACEAE

Polygala paniculata L.

A weed with tiny white flowers and an aromatic root, uncommon
growing in disturbed places. Only a single individual was seen.

W 3358.
PORTULACACEAE
Portulaca oleracea L.
"Tamole."' A prostrate, succulent, yellow-flowered herb growing

as a weed in sunny disturbed places. W 33/71.

RUBIACEAE
Gardenia taitensis DC.

"Tiale tiale." A white flowered shrub or small tree cultivated
around houses. Although this is native to the region, it was
probably introduced to Swains. W 3435, Bryan 1355, Diefenderfer s.n.

Guettarda speciosa L.

"Puapua."' A medium to large littoral forest tree with white flowers,
common in the forest. W 3394, Bryan 924 and 935.

Hedyotis romanzoffiensis (Cham.& Schlecht.)Fosb.

"Kautokiaveka", the Tokelauan name for it. This small shrub was
first reported from the island by the U.S.Exploring Expedition and
was later collected there by Lister in 1891. However, it was not
seen during the most recent visit. One knowledgeable islander said
he has not seen the plant growing on the island, but only its fruits
which have washed up on the beach. Perhaps, then, it no longer
occurs on Swains, but a more detailed search would be needed to
verify this.

Morinda citrifolia L.
"Nonu.'"' A small tree growing in the forest and in disturbed places.
This is probably an aboriginal introduction, since in Polynesia it is

known for its uses as a medicine, in preparing dyes, and as an
emergency food in times of famine. W 3419, Diefenderfer 8.

Spermacoce assurgens R.& P,

A small white-flowered weed common in disturbed places. It has
also been commonly known as Borreria laevis (Lam.)Griseb.
W 3376, Bryan s.n.

RUTACEAE

Citrus aurantium L,.

"Moli."" A cultivated species of orange tree found at Taulaga,
W 3431.

Citrus medica L.

"Tipolo," The cultivated citron with a thick, rough peel, growing
at Etena. Seen, but not collected.

SOLANACEAE

Capsicum frutescens L.

"Polo." The cultivated red pepper, growing at Taulaga. W 3421,
Diefenderfer s.n.

Physalis angulata L.

"Vivao."' A common weedy herb with whitish flowers. It has a small
edible fruit. W 3439.

Solanum uporo Dun.

"Polo." Not seen, but said by an islander to be growing in the
forest. A specimen collected by Schultz was verified by F.R.Fosberg
to belong to this species. Parham, however, records Solanum viride
R.Br. from Tokelau, but this is possibly a mistaken identification.
Schultz 8. This species was misidentified in the USFWS inventory.

TILIACEAE
Triumfetta procumbens Forst.f.
"Totolo." A woody, prostrate, creeping shrub with yellow flowers,

common on beaches and sometimes in disturbed sunny places inland.
W 3403, Bryan 934, Diefenderfer s.n., Schultz 15.

URTICACEAE
Laportea ruderalis (Forst.f.)Chew

A weed of shady disturbed places. It does not occur in Samoa, but
a related species, Laportea interrupta L., does. W 3377, Bryan s.n.

Pipturus argenteus (Forst.f.)Wedd.

"Fau vine" or "vine." A silvery-leafed tree with white succulent
fruit, occasional in disturbed places. In Samoa it is called
"fau soga" and in Tokelau it is "hau soga." The bast fiber is
used to make fishing lines, nets, and lashings. One islander
reported that the trees occurring in Tokelau have a sweet-tasting
fruit unlike those in Samoa. W 3404, Bryan 918 and 1369.

Procris pedunculata (Forst.f.)Wedd.
"Matavao.'' An epiphytic herb with red edible fruit. The Tokelau
name is "gahevao'', while in Samoa it is usually called "fua lole",
so the name is probably a local one. W 3355, Bryan 932.
VERBENACEAE

Stachytarpheta urticaefolia Sims

"Mautofu."" A shrub with purplish-flowers, common in sunny disturbed
places, W 3364.

MONOCOTYLEDONAE
AMARYLLIDACEAE
Crinum asiaticum L.
"Lautalotalo."' A large, white-flowered lily cultivated around

houses. W 3387, Bryan 929 and 1365.

Zephyranthes rosea (Spreng.)Lindl.

"Lili." Bryan records the name "suisana", but both of these names
appear to be local. A pink-flowered garden escape growing in grassy
areas around houses. W 3375, Bryan 955 and 1363.

ARACEAE

Alocasia macrorrhiza (L.)Schott
"Ta'amu."' A large aroid occasionally cultivated on Swains. Seen,
but not collected.

Colocasia esculenta (L.)Schott

"Talo." Taro is cultivated in swampy areas. The variety on Swains
is called "talo Niue" which is the common one in Samoa. Bryan 1364,
Diefenderfer s.n.

Cyrtosperma chamissonis (Schott)Merr.

"Pula'ta."" A large aroid commonly cultivated in swampy areas. In
Tokelau it is called "pulaka," Seen, but not collected.
COMMELINACEAE

Commelina diffusa Burm.f.

A blue-flowered herb common as a weed in wet places such as in the
taro and Cyrtosperma patches. W 3428, Diefenderfer 11.

CYPERACEAE

Cyperus brevifolius (Rottb.)Hassk,

A small sedge with green bracts,. common as a weed in grassy village
areas. W 3414.

Cyperus compressus L,

A low weedy. sedge occasional in disturbed areas. W 3412,

Cyperus javanicus Houtt.

A coarse sedge growing in wet places along the edge of the lagoon.
This is a widespread littoral species which is called "selesele"
in Samoa. W 3416.

Cyperus kyllingia Endl.

"Mutia."' A white-bracted sedge growing as a weed in grassy areas.
W 3368, Bryan 951.

Cyperus rotundus L.

"Mumuta.'' This nut grass is a weed of disturbed and grassy areas.
Its tubers are used to scent coconut oil. W 3429.

Eleocharis geniculata (L.)R.& S.
A low, clumped sedge growing in marshy areas along the edge of the
lagoon, mostly on a peninsula on the northeast corner. It was
reportedly collected in Samoa by Graeffe in 1871, but since it is

otherwise unknown from Samoa or the Tokelau Islands, this may be
in error. It does, however, occur in Fiji. W 3352A.

Fimbristylis cymosa R.Br.

"Tuiseé.'' An indigenous sedge common in sunny littoral areas and
also as a weed in open village areas. W 3360 and W 3417, Bryan
952, 954, and 1350, Diefenderfer s.n., Schultz 16.

Fimbristylis dichotoma (L.)Vahl

An erect weedy sedge common in open village areas. W 3361, Bryan
953.

GRAMINEAE
Axonopus compressus (Sw.)Beauv.
A prostrate grass common in open village areas. W 3412
Cenchrus echinatus L.

"Vao tuitui." The sand burr is a common weed of sandy and
grassy village areas. W 3370, Bryan 945 and s.n.

Chrysopogon aciculatus (Retz.)Trin.
A clump-forming weedy grass of open village areas. W 3369.

€ynodon dactylon L.

An occasional weedy grass of open village areas and disturbed
places. W 3436, Bryan 946,

Digitaria ciliaris (Retz.)Coel.

A small grass with digitate racemes, occasional in disturbed areas.
W 3438.

Eleusine indica (L.)Gaertn.

A coarse grass with digitate racemes, common in disturbed areas,
It is called "ta'ata'a" in Samoa. W 3362, Bryan 949 and 1362.

Eragrostis tenella (L.)Beauv. ex R.& S.

A small delicate grass occasional in open village areas, W 3363,
Bryan 950 and 1361.

Lepturus repens (Forst.f,)R.Br,

A clump-forming grass with an unbranched inflorescence that breaks
up into one-seeded segments, common on coastal sands and also as
a weed in disturbed places, W 3379 and 3390, Bryan 944 and 948.

Paspalum conjugatum Berg.

"Vaolima.'' A weedy grass with a t-shaped inflorescence, common
in disturbed places. W 3381, Bryan 947.

Paspalum distichum L. (usually known as P. vaginatum Sw.)

A clump-forming grass growing in large patches in marshy areas along
the edge of the lagoon. W 3353A, Bryan 938.

Saccharum officinarum L.

"Tolo."" Sugar cane was reported to be cultivated, at least until
recently, but it was not seen during the visit.

MUSACEAE

Musa paradisiaca L,

Two varieties of banana are growing on Swains Island, but no specimens
were collected during the visit. Diefenderfer 18.

PALMAE
Cocos nucifera L.
"Niu." A number of varieties of coconut are grown on Swains Island,

including one which in the young stage has an edible husk. Seen,
but not collected.

PANDANACEAE
Pandanus tectorius Park.
"Falayao.'' Wild screwpine is common in secondary forest and the

neglected coconut plantation, as well as along the seashore, W 3408,

Bryan 912 and 1346, Schultz 10.

Pandanus tectorius Park. var. ---?
"Falakai" or "fala Elise.". This cultivated screwpine is grown
for its edible fruit. The bases of the phlanges are chewed uncooked.
W 3432.
TACCACEAE

Tacca leontopetaloides (L.)0O.K.

"Masoa."’ The Polynesian arrowroot is cultivated and is somewhat
naturalized. In the Tokelau Islands it is called "mahoa."' W 3373,
Bryan 923, 1323, and 1351, Diefenderfer s.n.

ACKNOWLEDGEMENTS

The author wishes to thank Dr. F. Raymond Fosberg and Dr. Marie-
Héléne Sachet of the Smithsonian Institution for their help in identifying
the plant specimens collected on Swains Island. I also wish to thank my
colleagues, A. Binion Amerson, Jr., Terry Schwanner, and Warren Pulich
for their help while on the island, and the owner of Swains Island,
Wallace Jennings, for his information on the native names and uses for
the plants, and for his family's Polynesian hospitality afforded us
during the stay on the island.

The visit by the author was made during the USFWS inventory of the
wildlife and wildlife habitats of the Islands of American Samoa,
conducted by Environment Consultants, Inc. (contract. no. 11-16-0001-
5782FA of the Interior Department). For further details of the study
of the biota of Swains Island, see this report (1978, mimeograph copy).

Ed. note. -- A collection of plants was made on Swains Island and
Manihiki some years back and sent to the Smithsonian Institution by Mr.

Wm. S. Blankley, but no data were received with the specimens nor sup-
plied later.

BIBLIOGRAPHY

Bryan, E. 1974. Swains Island. Pacific Information Center, B.P. Bishop
Museum. Mimeograph copy.

Christensen, C. 1943. A revision of the Pteridophyta of Samoa. B.P.
Bishop Museum Bull. 177:1-138.

Christophersen, E. 1935. Flowering plants of Samoa--I. B.P. Bishop
Museum Bull. 128:1-221.

Christophersen, E. 1938. Flowering plants of Samoa--II. B.P. Bishop
Museum Bull. 154:1-77.

Clapp, R.B. 1968. The birds of Swain's Island south central Pacific.
Notornis XV(3) :198-206.

Fosberg, F.R. 1943. The Polynesian species of the genus Hedyotis.
B.P. Bishop Museum Bull. 174:1-101.

Holttum, R.E. 1977. The family Thelypteridaceae in the Pacific and
Australasia. Allertonia 1(3) :169-234.

Parham, B.E.V. 1971. The vegetation of the Tokelau Islands with
special reference to the plants of Nukuono Atoll. N.Z. Jour. Bot.
9:576-609.

Parham, B.E.V. 1972. Plants of Samoa. N,.Z. Dept. of Sci. and Indust.
Res., Info. Ser. 85:1-162.

Pickering, C. 1876. The geographical distribution of animals and plants
in their wild state. (From USEE, Voll; 19), pt. 2236-37 ™)r
Naturalists’ Agency, Salem, Mass.

Setchell, W.A. 1924. American Samoa: Part I. Vegetation of Tutuila
Island: Part II. Ethnobotany of the Samoans: Part II. Vegetation
of Rose Atoll. Carnegie Inst. Wash., Tort. Lab. Pap. 20:1-275.

USFWS. 1978. An inventory of the wildlife and wildlife habitats of the
islands of American Samoa. USFWS, Portland, Ore. Mimeograph copy.

Whistler, W.A. 1980. The vegetation of Eastern Samoa. Allertonia
2(2):45-190.

Folu Ane eas

Figure 2.

“SWAINS

Palms 100 feet

‘The central, brackish

ISLAND

water lageon of Swains Island.

Pil

Figure 3.

Figure 4.

Large, irregular chunks of algae floating in shallow
water of the lagoon of Swains Island.

5 RSA

3 < ie 2 ta CS cies ee :
" ML Zee eis 1 Gn tana AE ee APR oa
Sparse sand strand vegetation near Taulaga.

Sy a te pt. [2g

Figure 5. Scaevola-dominated shrubland near Etena.

Ae ee Pars Cae a tpraie
bias ee

Figure 6. Littoral forest on the south shore of Swains Island.

Open forest floor in littoral forest

dominated by Hernandia sonora.

Figure 8.

Forest on Swains Island dominated by

Pandanus tectorius.

Figure 7.

Pe
Figure 9.

Coconut palms on the lagoon shore of Swains Island.

tracks leading up to the copra shed.

ATOLL RESEARCH BULLETIN
No- 263

SHELF MARGIN REEF MORPHOLOGY: A CLUE TO MAJOR OFF-SHELF
SEDIMENT TRANSPORT ROUTES, GRAND CAYMAN ISLAND, WEST INDIES

HARRY H- ROBERTS

ISSUED BY
THE SMITHSONIAN INSTITUTION
WASHINGTON, D- C-, U-S-A-

SEPTEMBER 1983

SHELF MARGIN REEF MORPHOLOGY: A CLUE TO MAJOR OFF-SHELF
SEDIMENT TRANSPORT ROUTES, GRAND CAYMAN ISLAND, WEST INDIES

il)
Harry H. Roberts —

Abstract

Side-scan sonar, high-resolution seismic, and echo-sounder data,
coupled with the results of other reef-related studies on Grand Cayman
Island, show that abundant sediments have accumulated on the deep fore-
reef shelf. The most important accumulation sites are on the downdrift
northwest and southwest flanks of the island, where gradients from high
to low energy are maximized.

Shelf-margin reef morphology along the lee or western side changes
from a continuous sill-like structure that impounds sediment along most
of this sector to a discontinuous reef along the southwestern flank.
Isolated reef buttresses, separated by wide sediment-floored channels,
characterize this area, where abundant sediments are stored on the lower
forereef shelf. The wide channels between reef buttresses provide ave-
nues through which sediments produced in shallow-water environments can
be transported to deep off-shelf sites of deposition. Echo-sounder
traces off the shelf at the southwestern corner of the island display
characteristics suggesting depositional slopes. Shelf-margin reef mor-
phology strongly indicates that off-shelf sediment transport is occur-
ring along the southwestern flank of the island. Side-scan sonar data
were extremely valuable for rapidly evaluating the morphological vari-
ability of reefs on the forereef shelf.

Introduction

Recent studies of physical processes interacting with island reef
systems in trade-wind settings suggest that around-the-island gradients
in both wave energy and current energy favor transport and accumulation
of sediment along the lee coast and adjacent shelf (Roberts et al., 1975;
Murray et al., 1977; Davies, 1977; Roberts, in press). Both observations
and theory show that zones of intense currents (jets or rips) and zones
of weak currents (stagnation zones) are systematically distributed
around the shores of islands and that prisms of shelf sediment accumulate
in response to the deceleration of high-speed currents (Murray et al.,
1977). Within quasi-unidirectional wind and wave systems, major low
energy or sheltered zones around islands generally correspond to regions
where nearshore current fields display minimal velocities. In the
northeast trade-wind setting of the Caribbean, these low-energy zones
occur on the western sectors of islands.

Seem eres 21 iD VO. Bie ARON, OTRO) Ba Pile) =e Es ete 8
4Y Coastal Studies Institute, Louisiana State University, Baton Rouge

Manuscript received Jan. 1980--Eds.

Carbonate research conducted on the reefs and sediments of Grand
Cayman (West Indies), a trade-wind island that fits the above obser-
vations concerning energy distribution (Fig. 1), indicates that sedi-
ments have accumulated in abundance on the deep forereef shelf along the
western (lee) side of the island (Rigby and Roberts, 1976; Roberts,
1977). Although shallow fringing reefs, which are abundant sediment
sources, are not evident along the leeward coast, flourishing mid-shelf
and shelf-margin reefs are present. Higher energy shelves, compared to
low-energy shelves of Grand Cayman, tend to support more coral cover and
less open areas of sediment accumulation in both shallow and deep envi-
ronments (Roberts, 1974). Sediments produced by both physical and bio-
logical degradation of the reef framework in these higher energy shelf
areas appear to be largely trapped in the reef matrix and thereby di-
verted from primary routes of off-shelf sediment transport. Meaney
(1973), Moore et al. (1976), Land and Moore (1977), Ginsburg and James
(1973), and Hanna and Moore (1979) have studied various aspects of shelf
to basin sedimentation, including sediment budgets, facies relation-
ships, and stratigraphic history of off-shelf deposits. The study
reported in this paper provides additional data from side-scan sonar,
subbottom, and echo-sounder surveys (Fig. 1) concerning identification
of optimal sites for shelf-to-basin sediment transport associated with a
low-relief Caribbean island.

Objectives of this investigation were twofold. Firstly, from pre-
vious geological and physical process studies of Grand Cayman, the loca-
tion of important sediment sinks and general areas of maximum sediment
input to the shelf were identified. It then became important to deter-
mine if these areas of accumulation are also sites of significant sedi-
ment transport and if reef morphology is linked to this process. Sec-
ondly, the usefulness of side-scan sonar for reef-related studies was
tested.

Instrumentation

Three instruments were used in conjunction with accurate location
control. These instruments included a side-scan sonar system, a 3.5-kHz
subbottom profiler, and a linear chart recording fathometer. All in-
struments were deployed on an 1ll-metre boat, which served as a research
vessel. Instrumentation was operated simultaneously, and event marks
indicating position fixes were automatically recorded on all records at
l-minute intervals. The position fix numbers and distances from known
points were recorded on paper tape as a permanent record. Each instru-
ment is discussed below, with more emphasis being given to side-scan
sonar because of its usefulness in this study and its recent importance
to marine geology in general.

Side-Scan Sonar

The first operable side-looking sonars were made by the British in
the early 1960s. Side-scan did not become a valuable instrument for
marine surveys until the late 1960s. In the 1970s it has become increas-—
ingly important as standard instrumentation in marine survey work. For

ee a

the marine geoscientist, the development of side-scan sonar must be
considered a major technological milestone. Through the use of this
instrumentation, which is now readily accessible, it is possible to map
sea-floor surface features with complete coverage, a task very similar
to mapping from aerial photography. Previously, our understanding of
sea-floor morphology was derived primarily from profile data such as is
generated by a precision depth recorder. Between survey lines extrapo-
lations must be made, whereas adjacent side-scan sonar lines may be
spaced so that records overlap for continuous sea-floor coverage.
Recent development of systems that digitally acquire side-scan data and
play it back in an undistorted analog form is yet another major improve-
ment in this valuable instrumentation. In an undistorted format spatial
distributions of bottom features, textures, and shapes can be easily
assessed in a quantitative way, much like mapping and form analyses using
air photos.

The area of sea floor covered is a swath, commonly to 1,000 metres
(500 metres on each side of the source), rather than a line, as is the
case with profiling techniques. Objects on the sea floor reflect the
acoustic energy, which is received by the towed sonar source. Returned
signals are then amplified and printed as various tones on either wet or
dry paper. Precise measurements of distances between the vessel and a
reflector, as well as shapes, heights, and other relationships, are not
possible with conventional side-scan without corrections (Flemming,
1976). The new digital system offers a method for obtaining distortion-
free images and therefore the possibility of easily employing this
instrumentation for precise topographic mapping (Prior et al., 1979).

A conventional side-scan sonar system consists of three basic
units: (1) a transducer (or "fish'"), which is the underwater trans-—
mitting unit, (2) a steel-reinforced cable, which is used for towing the
fish and transmitting signals to the third component, (3) the recorder.

For optimum results from a side-scan sonar survey, precise naviga-
tional control is needed, and track lines should be arranged so that
adjacent records overlap on one channel. Without accurate navigational
control, both conventional and the new digital side-scans are of limited
use as instruments for collecting quantifiable data from the sea floor.

For research in coral reef environments side-scan sonar may be
used to collect data on reef shape, orientation, and general configu-
ration which may then be compared to physical expressions of the envi-
ronment such as wave direction and wave power. Density changes on the
side-scan sonograph may also represent well-defined facies changes,
e.g., muds to sands. This method is invaluable for the study of shelf
reefs that are too deep to be recorded by aerial photography. Other uses
in carbonate environments include the determination of sediment trans-—
port routes and sediment sinks in deep shelf areas where other methods of
observation may be difficult and time consuming.

The Klein side-scan system used in this study was coupled to the
3.5-kHz subbottom profiler, and records from both sensors were printed
on a single wet-paper recorder, which has three channels. The side-scan

has a frequency of 100 kHz with lookout ranges from 25 to 600 metres. We
found the 100-metre range to be optimal for the Grand Cayman study.

Subbottom Profiler

The subbottom profiler is designed so that it fits on the nose of
the side-scan sonar fish (Fig. 2). This unit operates at a frequency of
3.5 kHz and is designed to produce details of reflection events in the
upper 100-200 feet of the stratigraphic column, depending on the type of
sedimentary material. Unfortunately, the acoustic energy is transmitted
at relatively low power. In reef and reef-associated areas, the sea
floor is generally very hard, which causes much of the acoustic energy to
be reflected without penetrating the bottom. Only a few of our records
contained useful subbottom information. These records, however, pro-
vided additional data concerning sediment thickness on the forereef
shelf.

Fathometer Depth Recorder

A Raytheon Model DE-731 depth recorder was used in conjunction
with other instrumentation. This particular instrument was selected for
use because of its linear chart, versatile depth ranges, and porta-
bility. Although both the side-scan sonar and the 3.5-kHz subbottom
profiler records a bottom trace, the fathometer is a much more accurate
and convenient method of generating a bathymetric profile. The fathome-
ter was run on all survey lines during this study.

Our unit is equipped with a narrow-beam transducer, which gives
the best resolution of the sea floor. However, in rough seas this
transducer does not function well. The system will record in both feet
and fathoms (0-410 feet or fathoms is the depth recording range). The
operating frequency is 41 kHz, and the sounding rate is 270 pulses per
minute in FEET mode and 45 pulses per minute in FATHOMS mode.

Survey Position Fixing Instrumentation

A Decca Del Norte electronic range-range locating system which em-
ploys advanced microwave and digital techniques was used for survey con-
trol. This system has a "line of sight" capability, with maximum ranges
in the order of 80 km when both remotes and the master receiving antenna
are elevated. Distance is obtained by measuring the round-trip travel
time of signals transmitted between the master and the remote. Then, 10
or 100 path lengths, selected by digital filtering, are averaged to
determine each distance displayed. Ranges are obtained in a matter of
milliseconds. Positions can be resolved with this equipment to an accu-
racy of 1-3 metres. The instrumentation is very lightweight, easy to
install, and reliable under a full range of field conditions. The system
used in this study consisted of two remote stations (land based), a
master receiving station (boat based), and a printer. All units are
powered by two 12-volt car batteries. The remotes are deployed at known
survey control points along the coast (Fig. 3). These stations are
interrogated by the master unit on the boat, and the distance in metres
from each remote to the master antenna on the boat is printed out on

paper tape, along with position fix number and time. A l-minute rate for
these position checks was used in the Grand Cayman study. As position
fixes are taken every 1 minute, an event mark is simultaneously triggered
on the side-scan sonar, subbottom, and bathymetric records.

Shelf Morphology

The shelf surrounding Grand Cayman is narrow, ranging in width
from approximately 0.5 km to 2.0 km. Geomorphically, the most distinc-
tive features of any given shelf profile are two persistent submarine
terraces which can be traced around the entire island (Fig. 4). Although
differential reef growth and other generally slower forms of shelf
accretion account for a moderate degree of variability in terrace topog-
raphy, the seaward break in slope of the shallow terrace generally occurs
at a depth of 8-10 metres. The base of this shallow terrace averages 15
metres where the deep terrace is encountered. Except for the seaward
margin, most of the shallow terrace is a hardground surface with very
little, if any, sediment cover. It is sparsely colonized by reef-
building organisms, and is commonly dissected by shallow grooves (Fig.
5). On the lee side, however, localized areas of sediment accumulation
are associated with adjacent hardgrounds. Spurs and grooves are not
characteristic of the shallow terrace of the central lee shelf (Fig. 6).

The seaward margin of the shallow shelf break in slope supports a
prolific growth of coral superimposed on a distinct spur and groove struc—
ture. Well-defined ridges or spurs of living coral are prograding sea-
ward and building toward the surface. The linear depressions in the
shallow terrace surface are sometimes discontinuous and therefore
do not always extend to the seaward marginof the terrace. Most well-defined
grooves either reach the lower terrace or intersect other grooves until
the network extends across the upper shelf. It is clear, however, that
whether these grooves terminate upslope in actively growing fringing
reefs, as is generally the case, or in a limestone sea cliff, common on
lee side, they function as pathways for sediment transport to the lower
shelf.

Spur and groove structure is also typical of the deep shelf ter-
race. However, the landward portion of this terrace is frequently an
area of sediment accumulation (Fig. 7). Extremely coarse carbonate
material (cobble- to coarse-sand-sized sediment) is concentrated at the
base of coral-covered spurs of the shallow terrace. Particle size gener-
ally decreases to a bimodal sediment of coarse sand-sized constituents
in a silt- to clay-sized matrix near the shelf margin. Spurs of living
coral that extend landward from the actively growing shelf edge reef tend
to break the continuity of the lower shelf sediment belt. Considerable
variability is displayed in sediment plain characteristics, in terms of
both geometry and sediment properties. High-energy sectors of the shelf
tend to have coarse sediment plains that are highly segmented by spur
growth. Contrasting low energy shelves tend to have broader unbroken
areas of sediment accumulation. Most of these sites occur on the lee
(western) side of the island, where sediments can be quite fine grained
in localized areas. Depending on relationship to dominant wave direc-
tion, spurs that extend into the sediment plain may not be oriented

normal to the shelf edge. Roberts (1974) has shown that differences in
orientation between spurs and grooves on the shallow and deep terraces
are related to progressive changes in direction of dominant waves as they
intersect the shelf and refract across it.

A thriving reef community is present at the seaward edge of the
deep shelf terrace where an abrupt break in slope separates the shelf
from deeper off-shelf environments. Morphologically, the shelf margin
reef can vary from an unbroken ridge, through regularly spaced massive
coral buttresses separated by narrow sediment-floored grooves, to ir-
regularly spaced and widely separated coral buttresses. The degree to
which the deep reef morphology is exaggerated or amplified appears to
depend greatly on the wave energy conditions under which it developed
(Roberts, 1974). Along high-energy sectors of the shelf, massive and
regularly spaced living coral buttresses protrude into deep water (Fig.
8). These huge coral spurs occasionally coalesce, forming a wide variety
of tunnel and cavern structures. The massive buttresses generally have a
steep to overhanging seaward profile, with as much as 20-30 metres of
relief. Low-energy shelf-margin reefs support thriving coral communi-
ties (Fig. 9) but display less exaggerated buttress formation and less
steep offshelf profiles. Morphological elements of the reef at these
depths have coalesced to form a semicontinuous ridge at the shelf edge
which has grown to a height of 3-5 metres above the adjacent deep terrace
sediment plain. Inasmuch as this linear topographic feature is infre-
quently dissected by narrow grooves, it essentially forms a sill that
causes sediment to be impounded behind it.

Sediment Transport Routes and Variability
of Deep Reef Morphology

Previous research on Grand Cayman (Roberts, 1974; Roberts et al.,
19753; Murray et al., 1977) has demonstrated that strong westerly di-
rected currents exist along both the northern and the southern flanks of
the island (Fig. 1). At Grand Cayman's southwestern extremity, where
much of the research reported in this paper was concentrated, the com-
bined effects of shoaling waves, tidal currents, and westward-flowing
backreef lagoon currents from South Sound (Fig. 1) result in the trans-
port of sedimentary particles to the lee shelf, where they accumulate.

As discussed in a recent paper by Roberts (in press), continuous
reefs separating shallow backreef lagoons from the open shelf can be abun-
dant sources of sediment to deeper shelf and off-shelf environments.
Reefs of this description function as continuous sources of sedimentary
particles, first to backreef environments and subsequently to deeper
depositional settings outside the lagoon. Coarse sediment bodies tend
to accumulate behind the reef as a result of wave overwash processes and
at the adjacent backreef shoreline by swash action. Strong currents
develop in the downdrift ends of these systems, transporting sediment
outside the confines of the lagoon. Such flow is driven by both wind
stress on the lagoon and constant input of water to the backreef by
breaking waves that generate strong shore-normal surge currents at the
reef crest (Roberts and Suhayda, 1977; Suhayda and Roberts, 1977). These

processes provide the driving forces for creating a significant flow out
of the lagoon. The combined result is to export reef-derived and la-
goonal sediment to the adjacent forereef shelf. Although mean condi-
tions produce flows sufficient to move sand-sized sediments, storm
events create proportionately higher velocities and thereby become im-
portant sediment transport events.

Even though the movement of sediment to deep shelf environments is
reasonably well understood, processes responsible for transporting sedi-
ments off the shelf to deeper depositional sites have not been studied in
detail. Investigations of off-shelf sediment transport by Meaney
(1973), Moore et al. (1976), Land and Moore (1977), Ginsburg and James
(1973), and Hanna and Moore (1979), among others, have focused primarily
on the products of the transport process. They demonstrate that sedi-
ments generated in shallow reef and reef-associated environments are
moved off the shelf and into deepwater sedimentary environments. The
conditions responsible for displacing sedimentary particles from a shelf
domain to a basinal environment are not well understood. Most recently,
Hine and Newmann (1977), Hine et al. (in press), and Mullins et al. (in
press) have shown, from research on the margins of the Bahama Bank, that
large volumes of shallow-water sediments have engulfed Holocene shelf-
margin reefs and now reside on the deep flanks of the Bahamian platform.
They have attributed much of this off-bank transport to storm-related
processes. Islands such as Grand Cayman are somewhat more limited in
areas available for sediment generation as compared to vast shallow-
water platforms such as the Bahama Banks. There are, however, favored
sites where sediment accumulation around islands is focused by the
physical dynamics of the island system (Murray et al., 1977; Roberts, in
press).

Side-scan sonar data indicate that the morphology of Grand Cay-
man's shelf-margin reefs provides important clues to interpreting the
location of significant off-shelf sediment transport routes. On the lee
or western shelf, where sediments collect more abundantly than on higher
energy flanks of the island, there are long sections of shelf-margin reef
which have coalesced to form a relatively coherent ridge. Sediments are
impounded in the lee of this structure and can be transported over the
shelf edge only through narrow grooves (Fig. 10).

Grooves are active transport routes (Meaney, 1973) especially on
high-energy flanks of the island, where they are kept open by tidal ex-
change at the shelf edge and wave-related forces (Roberts et al., 1975,
1977). However, only limited amounts of sediment can be fluxed through
these narrow passageways to deeper sedimentary environments. Higher
energy shelves seem to maintain the integrity of a basic spur and groove
structure (Fig. 6), and sill-like structures do not generally develop.
The southwestern extremity of Grand Cayman is a site where maximum energy
gradients favor sediment deposition. Figures 11 and 12 illustrate the
large area of sediment deposition on the deep shelf, as well as the dis-
continuous nature of the adjacent shelf-margin reef. Rather than a
coalescence of reef elements to form a sill at the shelf edge, which is
typical of the Grand Cayman lee side, along the downdrift southwestern
flank of the island the shelf-margin reef breaks into irregularly spaced

reef masses or buttresses separated by wide channels. These wide chan-
nels provide free access for shelf sediments to deeper off-shelf envi-
ronments. Such shelf-margin reef morphology has probably developed in
response to a constant input of sediment to this accumulation site since
sea level rose above the level of the shelf edge (approximately 20-24
metres). Assuming that Grand Cayman has been subject to the same general
unidirectional wind and wave system since sea level was at the level of
the shelf edge, the island's southwestern flank has been a favored site
of sediment deposition. An abundant supply of sediments has probably
inundated once-living shelf-edge reefs and produced a mobile sediment
substrate that restricts coral attachment and growth. Apparently only
the highest topographic points have been able to perpetuate themselves
by continued reef growth.

Figure 13 summarizes the general sediment sinks and transport
routes associated with the southwestern flank of Grand Cayman Island.
Shallow-water accumulation zones are found in the sheltered areas of the
backreef lagoon. Over-the-reef currents, modulated by the tide and wind
stress, drive lagoonal water from east to west. Strong axial currents
capable of transporting sand-sized particles to the adjacent shelf
develop at the downwind end of the system. Significant shelf sediment
accumulation takes place only on the deep shelf terrace. Our 3.5-kHz
subbottom profiles show that these deposits are at least 5 metres thick.
High-resolution seismic data, showing more penetration from neighboring
Caribbean islands with similar shelf morphology, suggest that these
deposits may be up to 20 metres thick. Recent studies from the shelf and
shelf margin of Little Bahama Bank (Hine et al., in press) illustrate
Holocene sediment thicknesses in this range at preferred sites.

Shelf-margin reef morphology suggests that along high-energy
flanks of the island sediments move off the shelf through narrow, well-
defined groove systems. In contrast, the lee shelf-margin reef has fused
to essentially prohibit off-shelf transport of significant volumes of
sediment. Very narrow (1-3 metres), irregularly spaced grooves offer a
few minor pathways through which sediments may be carried off the shelf
(Fig. 10). Only at the northwest and southwest extremities of the
island where energy gradients are maximized do sediments accumulate in
such abundance that reef growth on the shelf edge is affected. At these
locations the shelf-margin reef becomes discontinuous (Fig. 12). Large
breaks in this sill-like structure are interpreted as major routes for
the movement of shallow-water sediments to deep sedimentary environ-
ments. Echo-sounder profiles of the southwestern island margin tend to
support the depositional nature of this site over steeper higher energy
flanks of the island (Fig. 14). Additional high-resolution seismic
work, coupled with a coring program, needs to be accomplished in order to
verify the extent of off-shelf deposits and to calculate a budget for
sedimentation during Holocene times at this preferred site.

Conclusions

Side-scan sonar, high-resolution seismic, and echo-sounder data,
coupled with results from previous studies on Grand Cayman, have led to

the following conclusions linking shelf-margin reef morphology and off-
shelf sediment transport:

1. Sediments accumulate in abundance on the down-drift south-
western flank of Grand Cayman, where gradients in wave and
current energy are maximized. An abundant source of sediments
to the southwestern shelf is associated with the east to west
flushing of South Sound, which is forced primarily by strong
reef overwash caused by breaking waves.

2. Shelf-margin reef morphology along the island's southwestern
flank changes from a continuous sill-like structure which im-
pounds sediments to a discontinuous reef characterized by iso-
lated reef buttresses. Wide avenues exist between reef but-
tresses through which sediments produced in shallow-water
environments can be transported to deep sites of deposition
off the shelf. Echo sounder profiles of windward to leeward
island margins suggest that the island's southwestern flank is
a zone of deposition, as evidenced by less steep "deposi-
tional" slopes and slump-like topography.

3. Side-scan sonar data proved to be particularly useful in this
study for determining details of shelf and shelf margin reef
morphology. This method of acquiring morphological details of
bottom features is rapid and quantitative, and allows the geo-
morphic variability of large areas of sea floor to be compared
without making direct underwater observations.

Acknowledgements

The research was performed under a contract between the Coastal
Sciences Program, Office of Naval Research, Arlington, Virginia, and the
Coastal Studies Institute, Louisiana State University, Baton Rouge.
Sneider and Meckel Associates of Houston, Texas, and Canadian Hunter Ex-
ploration Company of Calgary, Canada, supported a side-scan sonar study
of the forereef shelf of Grand Cayman Island which provided valuable
insight into the problem of offshelf sediment transport. Special thanks
go to Norwood H. Rector and Walker D. Winans for their invaluable tech-
nical support during the survey. Illustrations were prepared by Gerry
Dunn, and photographic work was accomplished by Kerry M. Lyle.

References

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Flemming, B. W. 1976. Side-scan sonar: a practical guide. Internat.
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Hanna, J. C., and Moore, C. H., Jr. 1979. Quaternary temporal framework
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Hine, A. C., Wilber, R. J., Lorenson, K., Bane, J., and Neumann, A. C.
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Land, L. S., and Moore, C. H., Jr. 1977. Deep forereef and upper island

slope, North Jamaica. In (Frost, S. H., Weiss, M. P., and
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Meaney, W. R. 1973. Sediment transport and sediment budget in the fore-
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PP-

Moore, C. H., Jr., Graham, E. A., and Land, L. S. 1976. Sedimentvtrans—
port and dispersal across the deep forereef and island slope (-55 m
to -305 m), Discovery Bay, Jamaica. J. Sedimentary Petrol., 46,
WASNGi.

Mullins, H. T., Neumann, A. C., Wilber, R. J., Hine, A. C., and Chinburg,
S. J. In the press. Carbonate sediment drifts in the northern
Straits of Florida. Amer. Assoc. Petrol. Geologists Bull.

Murray, S. P., Roberts, H. H., Conlon, D. M., and Rudder, G. M2 1977
Nearshore current fields around coral islands: control on sediment
accumulation and reef growth. Proc., 3rd Internat. Coral Reef
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of Miami, vol. 2, Geology, pp. 53-59.

Prior, D. B., Coleman, J. M., and Caron, R. Ek. 1979. Sea £lloorm mappime
microcomputer-assisted side-scan sonar. Proc. Internat. Symp. on
Remote Sensing of Environment, Ann Arbor, Mich., 23-27 April 1979,
pp W95—208%

Rigby, J. K., and Roberts, H. H. 1976. Grand Cayman Island: geology,
sediments, and marine communities. Geology Studies, Special Publ.
No. 4, Dept. of Geology, Brigham Young Univ., 121 pp.

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Atlantic Reef Comm., Univ. of Miami, Fisher Island, Miami Beach.
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CARIBBEAN SEA

4 Trisponder stations
se: Off-shelf bathymetric profiles + __ Current rips
[_] Areas surveyed <—<=a Mean drift

Figure 1. Location map of Grand Cayman Island showing the survey areas.

Figure 2. The Klein side-scan sonar fish plus 3.5-
KHz subbottom profiler used in this study.

Figure 3. Trisponder shore loca-
tion being installed in prepa-
ration for an offshore survey.

A_ MEAN SEA LEVEL A
1
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\

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5
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traces across Grand Cay-
0 100 200 26 man's narrow southern

forereef shelf (profile A-
A') and somewhat wider
western shelf (profile B-
BY) 6 Shallow and deep
terraces are character-
istic of each profile.
Large coral buttresses
with intervening grooves
are common along high-
energy flanks of the
island (A-A'). A rather
continuous shelf margin
reef is the norm on the lee
or western side of the
island (B-B').

B MEAN SEA LEVEL

SHALLOW TERRACE

Depth (m)

Figure 5. Surface of shallow terrace (depth ~3
metres). Note the lack of sediment cover, sparse
colonization of reef-building organisms, and shallow
groove.

Figure 6.

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Side-scan sonograph of the shallow shelf terrace on the lee
side of the island. Note the lack of spur and groove structure, isolated
areas of sediment accumulation, and hardgrounds. Water depth is 5-7 m.

Figure 7. Deep shelf terrace sediment plain that is
dissected in this locality by a linear spur con-
structed by a thriving reef community. Note the rip-
pled sediment. These structures are oscillation rip-
ples from recent storm waves (water depth 24 metres).

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Shelf edge

F=== Shallow reef Shallow shelf terrace

Sediment (dominantly sand)

(84 Shelf margin reef

Lagoon muds and rock floor

Figure 13. Sediment sinks and transport routes associated with the
south western flank of Grand Cayman Island (South Sound and adjacent
shelf areas). Arrows indicate sediment transport directions.

D SL 6
100
200
300
400
500
600
700
Ce D’

Figure 14. Echo-sounder profiles showing the variability in shelf and
shelf-margin slope morphology around the western end of the island. Note
the less steep and more "depositional" configuration to the lee side
profiles.

DEPTH, M

ATOLL RESEARCH BULLETIN
No- 264

AN ANNOTATED CHECK LIST OF THE CORALS OF AMERICAN SAMOA
BY

AUSTIN E- LAMBERTS

ISSUED BY

THE SMITHSONIAN INSTITUTION
WASHINGTON, D-C-, U-S-A-

SEPTEMBER 1983

AN ANNOTATED CHECK LIST OF THE CORALS OF AMERICAN SAMOA

by Austin E. Lamberts*

SUMMARY

Reef coral collections from American Samoa are in
the National Museum of Natural History, Smithsonian
Institution, Washington, D.C., and in the Hessisches
Landesmuseum, Darmstadt, W. Germany. The author has a
collection of 790 coral specimens for a total of 1547
items known to be from American Samoa.

A total of 177 species (including 3 species of
non-scleractinian corals) belonging to 48 genera and
subgenera (including the genera Millepora and Heliopora)
known to date are listed with data as of frequency of
occurrence and habitat.

INTRODUCTION

The territory of American Samoa comprises the six
eastern islands of the Samoan archipelago. It is located
in the tropical central south Pacific (14°S latitude,
170°w longitude) about 2300 nautical miles (4420 km)
southwest of Hawaii and 80 miles (130 km) southeast of
Western Samoa. Five of the islands are volcanic in
origin and are aligned along the crest of a discontinuous
submarine ridge which extends over 300 miles (480 km) and
tends roughly northwest by southeast. My collecting was
done on the five major inhabited islands of American
Samoa which are the largest, Tutuila, Aunu“u (a small
island located 1 mi (1.6 km) off the southeast coast of
Tutuila), Ofu, Olesega, and Ta“u. The latter three
islands are collectively referred to as the Manu“a group
and lie about 66 miles (106 km) east of Tutuila. An
uninhabited coral atoll, Rose Island is located 100 mi
(161 km) east of Tutuila. One other island, Swains
Atoll, is considered part of the Samoan group but is
geographically a part of the Tokelau Island group and is
not included in this study.

The first scientist to reach the Samoan (Navigator)
Islands was probably Dr. Charles Pickering, a physician
maturalist who explored Rose Atoll when ships of the
United States Exploring Expedition under Capt. Wilkes met

*1520 Leffingwell, N.E., Grand Rapids, Mich., 49505
Revised manuscript received March 30, 1981--Eds.

there in October 1839. Specimens he collected were added
to those of James D. Dana who visited Tutuila for only
four hours and made no coral collection in Samoa. [In
1918 Dr. Alfred Mayor headed an expedition to American

Samoa under the auspices of the Carnegie Institution of
Washington. During three visits he collected 354 coral

specimens which were donated to the National Museum of
Natural History (NMNH), Smithsonian Institution and were
described by Hoffmeister in 1925. In 1941 the NMNH
received a collection of 380 corals from Mrs. Thompson.
They were acquired while her husband served wih the U.S.
Navy. These specimens were accompanied with no data
although it was indicated that all were collected about
Tutuila. tin 1967 Drs D.K. Hofman obtained) 23yiconat
specimens from Tutuila. These are now at the Hessisches
Landesmuseum in Darmstadt, W. Germany and were reported
by Pillai and Scheer dn 1973)...” This’ study) duncorpoxra'tels
these data with material I gathered in American Samoa.

MATERIAL AND METHODS

My collections of 690 specimens were made during
four trips to Samoa between 1973-79. Specimens were
taken from reef flats but mostly from deeper waters using
mask and snorkel. Friends participated when SCUBA was
used. All specimens were numbered at time of collection
and data was recorded in a permanent record. Many
photographs were taken of live specimens. All were
cleaned, dried and transported to my home in Michigan for
further study. They will eventually be placed in the
collections of the Bernice P. Bishop Museum, Honolulu,
Hawaii.

A typical coral reef as herein described may start
in shallow inshore waters or a lagoon which might be 2 m
deep, ascends to a shallow fore-reef, then to a reef
crest usually out of water at low tide, a surge zone with
spur and groove formation on windward (SW, Samoa), a
sharp reef front dropping 5 - 10 m to a reef terrace and
gradually descending to deep water. Most of the reefs
have passes (Samoan:ava) of variable width and depth.
The maximum width of reefs in American Samoa is about 500
m and most are much narrower. Taema Bank is a drowned
barrier reef some three miles off the entrance of Pago
Pago harbor. Also mentioned is the Airport lagoon which
was dredged in stages from 1942 to 1973 during
construction of Pago Pago International Airport complex.
This lagoon lies between the runway and the Nu“uuli
fore-reef. The dredgings contained some recent fossil
coral (Goniopora, Acrhelia) species not found live in
Samoa along with mollusc shells of the genus Cypraea with
nacre virtually unblemished.

Corals are listed systematically by genera and
alphabetically by species. Relative abundances are
listed as: abundant when they are readily found in large
numbers on most reef complexes; the 41 species listed as
common are found on most reefs; the 45 species termed
sporadic may be common but are noted in my own collection
data a few times; those listed as rare were found only
once or twice. In such instances the collection location
is given with place names of Samoan villages which
fronted the reef. Depths at which specimens were found
are listed in meters. The Aua line mentioned is that of
Mayor”’s study in 1918.

This paper lists all corals by specific names given
in the literature as coming from American Samoa.
Studer”’s (1901) specimens probably did not come from
there and have not been included. Specific names which
have been changed are listed within brackets with their
synonyms. Behind each entry (H) appears if it was
described by Hoffmeister (1925) and P&S if it was
described by Pillai and Scheer (1973).

ANNOTATED LIST

Class ANTHOZOA

Subclass HEXACORALLIA Haeckel, 1896

Order SCLERACTINIA Bourne, 1900

Suborder ASTROCOENIINA Vaughan & Wells, 1943
Family ASTROCOENLIIDAE Koby, 1890

Subfamily ASTROCOENIINAE Yabe & Sugiyama, 1935
Genus STYLOCOENIELLA Yabe & Sugiyama, 1935

Stylocoeniella armata (Ehrenberg, 1834).
Sporadic, lagoons, under rocks or coral growth,
(1-2m)

Family THAMNASTERIIDAE Vaughan & Wells, 1943
Genus PSAMMOCORA Dana, 1846

Psammocora contigua (Esper, 1795) (H)
Abundance, Inner reef flats, lagoons (0-3m)
Psammocora folium Umbgrove, 1947
Rare, Reef face; Fagasa (3m)
Psammocora nierstraszi van der Horst, 1921
Rare, Reef flats (0-1m)
[Psammocora samoensis Hoffmeister, 1925] (H)
Synonym P. nierstraszi
Psammocora superficialis Gardiner, 1898
Locally common. Reef edge, reef slopes (0-3m)

Psammocora contigua var. tutuilensis Hoffmeister 1925

(H)
Rare, Reef flats (1-2m)

Family POCILLOPORIDAE Gray, 1842
Genus STYLOPHORA Schweigger, 1819

Stylophora mordax Dana, 1846
Sporadic, Passes, reef fronts & terraces (3-10m)

Genus SERIATOPORA Lamarck, 1816

Seriatopora hystrix var. gracilis Dana, 1846
Rare, Masefau & Fagatele Bays (2-5m)

Genus POCILLOPORA Lamarck, 1816

Pocillopora ankeli Scheer, 1975
Rare, Fagasa reef front (3m)
Pocillopora brevicornis Lamarck, 1816 (H)
Common, Back reefs (1-2m)
Pocillopora cf. bulbosa Ehrenberg, 1834
Sporadic, Lagoons (1-3m)
Pocillopora damicornis (Linnaeus, 1758) (H & P&S)
Abundant, Inshore lagoons, reef flats (0-5m)
Pocillopora danae Verrill, 1864
Rare, Masefau Bay (1m)
Pocillopora eydouxi Edwards & Haime, 1816 (H)
Common, Reef fronts, surge zones (1-5m)
Pocillopora cf. setchelli Hoffmeister, 1929
Rare, Reef flat near surge zone (0-1m)
Pocillopora verrucosa (Ellis & Solander, 1786)
Abundant, Reef flats, lagoons, reef fronts (1-10m)
Pocillopora woodjonesi Vaughan, 1918
Common, one area in Masefau Bay only (2-3m)

Family ACROPORIDAE Verrill, 1902
Genus ACROPORA Oken, 1815

Acropora abratanoides (Lamarck, 1816)
Rare, Fagasa (2m)
Acropora africana (Brook, 1893) (H)
Rose Atoll, Dr. Mayor.
Acropora aculeus Dana, 1846)
Sporadic, Reef slopes, Bays (1-3m)
Acropora arbuscula (Dana, 1846)
Locally common, Faga”“itua pass (2-3m)
Acropora aspera (Dana, 1846)
Abundant, Lagoons, back reefs (0-3m)
Acropora brueggemanni (Studer, 1878)
Rare, Reef slope, Aua line (3m)

Acropora cerealis (Dana, 1846)
Common, Back reefs, grooves in reef crest (0-2m)
Acropora clathrata (Brook, 1893)
Rare, Taema Bank (25m)
Acropora corymbosa (Lamarck, 1816) (H, P&S)
Sporadic, Masefau (1-3m)
Acropora crateriformis (Gardiner, 1899) (H)
Locally common, reef flats, passes (1-3m)
Acropora cuspidata (Dana, 1846)
Rare, Faga”°“itua, Masefau passes (1-2m)
[Acropora symbicyathus (Brook, 1893)] (H)
Synonym A. nasuta
Acropora cytherea (Dana, 1846)
Sporadic, Reef face, Bays (2-20m)
Acropora delicatula (Brook, 1893)
Rare, Fagasa ( (2m)
Acropora diversa (Brook, 1893)
Locally common, Aunu“u, Olesega (0-2m)
[Acropora fructicosa (Brook, 1893)] (H)
Synonym A. humilis
Acropora exigua (Dana, 1846) (H)
Sporadic, Lagoons, usually with A. formosa
(2-5m)
Acropora formosa (Dana, 1846) (H)
Abundant, Huge thickets; lagoons (0-20)
[Acropora hebes (Dana, 1846] (H)
Synonym A. aspera
Acropora humilis (Dana, 1846)
Abundant, Reef crests, surge zones, passes (0-2)
Acropora horrida (Dana, 1846)
Rare, Ofu lagoon (1m)
Acropora hyacinthus (Dana, 1846) (H, P&S)
Abundant, All reef fronts, passes (1-20m)
Acropora intermedia (Brook, 1893)
Locally common, Passes, lagoons (2-5m)
Acropora latistella (Brook, 1893)
Common, Reef crests (1-3m)
[Acropora leptocyathus (Brook, 1893)] (H)
Synonym A. humilis
Acropora longicyathus (Edwards & Haime, 1860)
Rare, Faga° itua pass (3m)
Acropora massawensis (von Marenzellar, 1906) (H)
Rare, Aua line, Dr. Mayor. Taema Bank (0-25m)
Acropora millepora (Dana, 1846)
Rare, Nu“uuli reef crest (0-1)
Acropora granulosa (Edwards & Haime, 1860)
Rare, Masefau (20m)
Acropora nana (Studer, 1878)
Common, Back reefs, grooves (102m)
Acropora nasuta (Dana, 1846)
Common, Reef crest, reef slopes, Bays (1-3m)
Acropora nobilis (Dana, 1846) (H)
Sporadic, passes, lagoons (3-5m)
Acropora pagoensis Hoffmeister, 1925 (H)

Rare, Dredged, Taema Bank, Dr. Mayor
Acropora palmerae Wells, 1954
Sporadic, Reef crest, surge zones (0-1m)
Acropora palifera (Lamarck, 1816) (H)
Sporadic, Reef fronts in bays (1-3m)
Acropora paniculata (Verrill, 1902)
— Rare, Faga itua pass (1-2m)
Acropora pinguis Wells, 1950
Rare, Fagamalo and Fagatele Bays (1-2m)
[Acropora prolixa (Verrill, 1866] (H)
Synonym A. longicyathus
Acropora pulchra (Brook, 1893) (H)
Common locally, Inner reef flat (1-2m)
[Acropora quelchi (Brook, 1893)] (H)
Synonym A. cerealis
Acropora rambleri (Bassett-Smith, 1890)
Rare, Masefau (20m)
Acropora robusta (Dana, 1846)
Sporadic, Reef slopes, grooves (1-5m)
Acropora rotumana (Gardiner, 1899) (H, P&S)
Common, Reef edge, surge zones (0-2m)
[Acropora samoensis (Brook, 1893)] (H)
Synonym A. humilis
Acropora schmitti Wells, 1950
Rare, Reef slope, Aua line (3m)
Acropora splendida Nemenzo, 1967
Rare, Airport lagoon, Aasu Bay (2-3m)
Acropora squarrosa (Ehrenberg, 1834)
Rare, Taema Bank (20m)
Acropora surculosa (Dana, 1846)
Sporadic, Reef slope (2-5m)
Acropora spicifera (Dana, 1846)
Sporadic, Passes, bays (1-3m)
[Acropora syringodes (Brook, 1893)] (H)
Synonym A. nana (7)
Acropora teres (Verrill, 1866) (H, P&S)
Rare, Reef flat (1-3m)
[Acropora tutuilensis, Hoffmeister, 1925] (H)
Synonym A. clathrata, A. rotumana
Acropora valida (Dana, 1846) (H)
Sporadic, Lagoons (1-2m)
[Acropora vanderhorsti, Hoffmeister 1925] (H)
Synonym A. intermedia
Acropora variabilis (Klunzinger, 1879)
Locally common, Lagoons, Olesega, Ofu
Acropora sp. l
Sporadic. Passes, Colonies of heavy stalks with
blunt tops, brilliant blue in situ (1-2m)

Genus ASTREOPORA de Blainville 1830
Astreopora cucullata Lamberts, 1980

Sporadic, Faga°“itua pass Pago Pago Bay (2-4m)
Astreopora listeri Bernard, 1896

Rare, Reef flats (0-1m)
Astreopora myriophthalma (Lamarck, 1816)
Sporadic, Reef flats, lagoons, bays (0-3m)
[Astreopora profunda Verrill 1875] (H, P&S)
Synonym A. myriophthalma (usually when free
rolling) | MA es i>
Astreopora scabra Lamberts, 1982
Sporadic, Reef flats, lagoons (0-3m)

Genus MONTIPORA de Blainville 1830

Montipora berryi Hoffmeister 1925 (H)
Sporadic, Lagoons, reef flats (1-4m)
Montipora bilamina Bernard 1897
Rare. WA pone lagoon (3m)
Montipora caliculata (Dana, 1846)
" Sporadic, passes, back reefs (1-3m)
Montipora composita Crossland 1952
Sporadic, Reef face in bays, passes (1-3m)
Montipora elschneri Vaughan 1918 (H)
Sporadic, Reef flats (0-1m)
Montipora foveolata (Dana, 1846)
Rare, Faga°“itua pass (0-1m)
Montipora marshallensis Wells, 1954
Rare, Faga”“itua pass (1-3m)
Montipora ehrenbergii Verrill, 1875
Common, Lagoons, back reefs (0.5-2m)
Montipora cf. pulcherrima Bernard, 1897
Rare, Faga°“itua fore reef (1-2m)
Montipora acutata Bernard, 1897
Rare, Masefau (30m)
Montipora socialis Bernard, 1897
Sporadic, Reef face (0-2m)
Montipora spumosa (Lamarck, 1816) (H)
Sporadic, Reef flats (0-2m)
Montipora trabeculata Bernard, 1897 (H)
Sporadic, Ta“u, Olesega reef flats (1-3m)
Montipora tuberculosa (Lamarck, 1816) (H)
Common, Reef flats, lagoons (0-2m)
[Montipora vaughani Hoffmeister 1925] (H)
Synonym M. socialis
Montipora venosa (Ehrenberg, 1834) (H)
Common, lagoons, back reefs (0-3m)
Montipora verrilli Vaughan, 1970 (H)
Common, Reef flats, fore reefs (0-3m)

Suborder FUNGIINA Verrill 1865
Superfamily AGARICIICAE Gray 1847
Family AGARICLIDAE Gray 1847

Genus PAVONA Lamarck 1801

Pavona clavus Dana, 1846
Sporadic, Reef slopes, passes (3-10m)

Pavona decussata Dana, 1846 (H)
Common, Lagoons, back reefs (1-3m)
Pavona divaricata Lamarck, 1846 (H)
Common, Reef flats, back reefs, passes (0-3m)
Pavona duerdeni Vaughan, 1907
Rare, Taema Bank (30m)
Pavona fondifera Lamarck, 1816 (H)
Abundant, Reef flats (0-1m)
Pavona cf. gigantea Verrill, 1869
Rare, Taema Bank (30m)
Pavona maldivensis (Gardiner, 1905)
Rare, Masefau (2m)
Previously listed as P. (pseudocolumnastrea)

pollicata Wells, 1954
Pavona varians Verrill, 1864

Common, Lagoons, reef edges, Taema Bank (2-30m)
Genus GARDINEROSERIS Scheer, 1975

Gardineroseris planulata (Dana, 1846)
Sporadic, Reef crests, surge zones (0Q-I1m)

Genus LEPTOSERIS Edwards & Haime 1849

Leptoseris gardineri van der Horst, 1921 (H)
Dredged, Dr. Mayor, Pago Pago Harbor (25-50m)
Leptoseris scabra Vaughan, 1907 (H)
Dredged, Dr. Mayor, Pago Pago Harbor (15-30m)

Genus PACHYSERIS Edwards & Haime 1849

Pachyseris carinata Brueggemann 1879 (H)
Rare, Masefau (2m)

Pachyseris levicollis (Dana, 1846) (H)
Dredged, Dr. Mayor, Pago Pago Harbor; Airport
dredgings.

Pachyseris speciosa (Dana, 1846) (H)
Dredged, Dr. Mayor, Pago Pago Harbor (15-30m)
Locally common, Masefau (30m)

Genus COSCINARAEA Edwards & Haime 1848

Coscinaraea columna (Dana, 1846) (H)
Sporadic, Reef fronts, terraces (1-20m)

Superfamily FUNGIICAE Dana 1846
Family FUNGIIDAE Dana 1846

Genus FUNGIA Lamarck 1801

Fungia concinna Verrill, 1864 (P&S)
Rare, Airport lagoon (1m)

Fungia echinata (Pallas, 1766)
Sporadic, Masefau (30m)

Fungia fungites (Linnaeus, 1758) (H)
Common, Reef terraces, Bays (2-5m)
Fungia granulosa Klunzinger 1869
Rare, Pago Pago Bay (30m)
Fungia patelliformis Boschma, 1923 (H)
Dredged, Dr. Mayor, Pago Pago Harbor (25-30m)
Fungia paumotensis Stutchbury, 1833 (H)
Rare, Airport lagoon (1m)
Fungia repanda Dana, 1846
Locally common, Masefau (3-5m)
Fungia scutaria Lamarck, 1816
Rare, Masefau reef (2m)

Genus HERPOLITHA Escholtz 1826

Herpolitha limax (Houttyn, 1772)
Locally common, Masefau (30m)
Herpolitha crassa Dana, 1846
Rare, Afono Bay (15m)

Genus LITHACTINIA Lesson 1831

Lithactinia novaehiberniae Lesson 1831
Thompson collection, no data

Superfamily PORITICAE Gray 1842
Family PORITIDAE Gray 1842

Genus GONIOPORA de Blainville 1830

Goniopora parvastella Ortman, 1888
Sporadic, Faga~itua Pass (3m)

Goniopora samoa [I Bernard, 1903
Locally common, Airport dredgings

Goniopora sp. 1 cf. somaliensis Vaughan, 1907
Rare, Reef slopes, Aua line (2m)

Goniopora sp. 2 cf. gracilis (Bassett-Smith, 1890)
Rare, Utelei, Olesega (1-2m)

Goniopora sp. 3 cf. traceyi Wells, 1954
Rare, Olesega (1-2m)

Genus PORITES Link 1807

Porites andrewsi Vaughan, 1918 (H, P&S)

Abundant, Reef flats, back reefs (0-2m)
Porites latistella Quelch 1886

Locally common, Airport lagoon (0-2m)
Porites matthaii Wells, 1954

Sporadic, Reef flats, back reefs (0-1m)
Porites pukoensis Vaughan, 1907 (H)

Rare, Aua line (3m)
Porites lobata Dana, 1846 (H, P&S)

Sporadic, Back reefs, lagoons (0-5m)
Porites lutea Edwards & Haimes, 1851 (H, P&S)

Abundant, All collecting sites (0-30m)
Porites lutea var. haddoni Vaughan, 1918 (H)
“Common, Reef flats, lagoons (0-5m)
Porites murrayensis Vaughan, 1918 (H)

Rare, Faga°itua lagoon (1m)

Porites queenslandi septima Bernard, 1905

Rare, Taema Bank (30m)

Porites lichen Dana, 1846
Sporadic, Surf zones, passes, Taema Bank (0-30m)

Genus PORITES (SYNARAEA) Verrill 1864

Synaraea horizontalata Hoffmeister, 1925 (H)
Sporadic, Masefau, Pago Pago Bay (10-30m)
Synaraea faustino Hoffmeister, 1925 (H)
Dredged by Dr. Mayor (7-12m)
Synaraea undulata Klunzinger, 1879 (H)
Abundant, Reef flats, passes, lagoons (0-5m)

Genus ALVEOPORA de Blainville 1830

Alveopora allingi Hoffmeister, 1925 (H)

Dredged, Dr. Mayor, Pago pago Harbor (25-35m)
Alveopora verrilliana Dana, 1872 (H)

Sporadic, Reef flats, lagoons, back reefs (0.5-5m)
Alveopora viridis (Quoy & Gaimard, 1827)

Rare, Fagasa, Utelei (bright green) (1-2m)

Suborder FAVIINA Vaughan & Wells 1943
Superfamily FAVIICAE Gregory 1900
Family FAVIIDAE Gregory 1900
Subfamily FAVIINAE Gregory 1900

Genus FAVIA Oken 1815

Favia favus (Forskaal, 1775) (H)
Sporadic, Reef flats (0-3m)
Favia laxa (Klunzinger, 1879)
Rare, Fagasa (15m)
Favia pallida (Dana, 1846) (H, P&S)
Sporadic, Reef flats, reef terraces (0-5m)
Favia rotumana (Gardiner, 1899) (H)
Common, Passes, bays (1-10m)
Favia speciosa (Dana, 1846)
Rare, Faleosoa (on Ta“u) (0.5m)
Favia stelligera (Dana, 1846) (H)
Sporadic, Reef flats, reef terrces (0-10m)

Genus FAVITES Link 1807

Favites abdita (Ellis & Solander, 1786) (H)
Common, Reef flats (0-3m)

Favites halicora (Ehrenberg, 1834) (H)
Common, Reef flats, Taema Bank (0-30m)

Favites chinensis Verrill, 1866

Rare, Masefau, Faga°itua reef flat (1m)
Favites russelli Wells, 1954

Rare, Taema Bank (30m)

Genus GONIASTREA Edwards & Haime 1848

Goniastrea edwardsi Chevalier 1971
Rare, Breaker’s Point reef flat (0.5m)
Goniastrea favulus (Dana, 1846)
Sporadic, Faga°“itua pass (0-2m)
Goniastrea palauensis Yabe & Sugiyama 1934
Rare, Taema Bank (30m)
Goniastrea pectinata (Ehrenberg, 1834) (H)
Rare, Poloa, Fagamalo (1-2m)
Goniastrea retiformis (Lamarck, 1816) (H)
Sporadic, Reef flats, passes (0-3m)

Genus PLAYTGYRUS Ehrenberg 1834

[Platygyrus daedalea (Ellis & Solander, 1786)]
Name pre-occupied by a Forskaal species,
Synonym P. rustica

[Meandra esperi (Edwards & Haime, 1857)]
Synonym P. rustica

Platygyrus lamellina Ehrenberg, 1834 (H)

Rare, Masefau, Taema Bank (1-20m)

Platygyrus rustica (Dana, 1846)

Common, Reef flats, lagoons (0-5m)

Genus LEPTORIA Edwards & Haime 1848
Leptoria phrygia (Ellis & Solander, 1786) (H, P&S)
Common, Reef flats to Taema Bank (0-30m)
[Leptoria tenuis (Dana, 1846)] (H)
Synonym L. phrygia
Genus OULOPHYLLIA Edwards & Haime 1848

Oulophyllia crispa (Lamarck, 1816)
Rare, Masefau (25m)

Genus HYDNOPHORA Fisher de Waldheim 1807
Hydnophora exesa (Pallas, 1766)
Sporadic, Passes, bays, Taema Bank (2-30m)
Hydnophora microconos (Lamarck, 1816) (H, P&S)
Common, Reef flats to Taema Bank (0-30m)
Subfamily MONTASTREINAE Vaughan & Wells 1943
Genus MONTASTREA de Blainville 1830

Montastrea curta (Dana, 1846)

Common, Lagoons, reef flats, fore-reefs (0-5m)
[Orbicella curta Dana, 1846]
Synonym M. curta

Genus PLESIASTREA Edwards & Haime 1848

Plesiastrea versipora (Lamarck, 1816) (P&S)
Rare, Falesao (im)

Genus DIPLOASTREA Matthai 1914

Diploastrea heliopora (Lamarck, 1816) (P&S)
Sporadic, Reef slopes, Bay terraces (0.5-10m)

Genus LEPTASTREA Edwards & Haime 1848

Leptastrea purpurea (Dana, 1846) (H)
Abundant, Inshore waters, reef flats (0-1m)
Leptastrea bottae Milne-Edwards & Haime 1848
Rare, Fagamalo (1m)

Genus CYPHASTREA Edwards & Haime 1848

Cyphastrea chalcidicum (Forskaal, M/S)
Rare, Taema Bank (30m)

Cyphastrea cf. gardineri Matthai, 1914
Sporadic, Inshore waters, lagoons (0-1m)

Cyphastrea microphthalma (Lamarck, 1816) (H)
Rare, Dredged by Dr. Mayor (35m)

Genus ECHINOPORA Lamarck 1816

Echinopora lamellosa (Esper, 1795)
Locally common, Faga”“itua pass, Masefau (3-5m)

Family OCULINIDAE Gray 1847
Subfamily GALAXINAE Vaughan & Wells 1943

Genus GALAXEA Oken 1815

Galaxea clavus (Dana, 1846)
Sporadic, Reef terraces, Leone, Fagatele Bays
(3-5m)
Galaxea fascicularis (Linnaeus, 1758) (H, P&S)
Common, Reef flats, terraces (0-25m)
Genus ACRHELIA Edwards & Haime 1849

Acrhelia horrescens (Dana, 1846)
Rare, Airport dredgings

Family MUSSIDAE Ortman 1890

Genus ACANTHASTREA Edwards & Haime 1848

Acanthastrea echinata (Dana, 1846)
Rare, Poloa (1m)

Genus LOBOPHYLLIA de Blainville 1830

[Lobophyllia corymbosa (Forskaal, 1775)]

Reported by Pillai & Scheer. No data. (P&S)

Lobophyllia cestata (Dana, 1846)

Common, Passes, reef slopes, terraces (2-5m)

[Mussa sinuosa (Lamarck, 1816)] (H)
Synonym L. costata

Genus SYMPHYLLIA Edwards & Haime 1848

Symphyllia nobilis (Dana, 1846) (H)
Rare, Matu”“u, Fagatele Bay (0-4m)

Family MERULINIDAE Verrill 1866
Genus MERULINA Ehrenberg 1834

Merulina ampliata (Ellis & Solander, 1786) (H)
Rare, Fagatele Bay (3m)

Family PECTINIIDAE Vaughan & Wells 1943
Genus ECHINOPHYLLIA Klunzinger 1879

Echinophyllia aspera (Ellis & Solander, 1786)
Rare, Utelei (30m)

Genus OXYPORA Saville-Kent 1871

Oxypora lacera (Verrill, 1864)
Rare, Masefau (3m)

Suborder CARYOPHYLLIINA Vaughan & Wells 1943

Superfamily CARYOPHYLLIICAE Gray 1847
Family CARYOPHYLLIIDAE Gray 1847
Subfamily EUSMILIINAE Edwards & Haime 1857

Genus EUPHYLLIA Dana 1846

Euphyllia glabrescens (Chamisso & Eysenhardt,
Sporadic, Masefau, Avatele passage (3m)

Genus PLEROGYRA Edwards & Haime 1848

Plerogyra simplex Rehberg, 1892
Rare, Utelei reef front (1m)

Suborder DENDROPHYLLIIDA Gray 1847
Family DENDROPHYLLIIDAE Gray 1847

LB2IL) (CE!)

14
Genus TUBASTREA Lesson 1831

Tubastrea coccinea Lesson, 1831

Rare, Aua reef slope, Faga”“itua pass (1-3m)
[Dendrophyllia diaphana Dana, 1846] (H

Synonym Tubastrea aurea = T. coccinea

Genus TURBINARIA Oken 1815

Turbinaria frondens Dana, 1846

Sporadic, Leone terrace, Masefau terrace (2-6m)
Turbinaria peltata (Esper, 1794)

Rare, Massefau (30m)

Subclass OCTOCORALLIA Haeckel 1896
Order COENOTHECALIA Bourne 1895
Family HELIOPORIDAE Moseley 1876

Genus HELIOPORA de Blainville 1834

Heliopora coerulea (Pallas, 1766)
Common, Reefs of Ta“u, Ofu, and Olesega only (0-2m)

Class HYDROZOA Huxley 1856
Order MILLEPORINA Hickson 1901
Family MILLEPORIDAE Fleming 1828

Genus MILLEPORA Linnaeus 1758

Millepora platyphylla Hemprich & Ehrenberg, 1834
Common, Reef flats, reef fronts (0-3m)
Millepora tenera Boschma 1949
Locally common, Ofu back reefs (1-2m)
{[Millepora alcicornis Linnaeus, 1758] (H)
Synonym Probably M. tenera
[Millepora truncata Dana, 1846] (H)

Synonym M. platyphylla
CONCLUSIONS

This check list is neither exhaustive nor final.
No attempt was made to collect on every reef and most
reef terraces remain relatively unexplored. In all, 174
species of scleractinian corals are presented. These
represent 48 genera and subgenera. Also listed are 3
species, one a Heliopora and two of Millepora; though
not scleractinian, they certainly are reef formers. In

all there are 199 nominal listings of which I considered
22 invalid.

Because a coral species was reported from Samoa
does not mean that it can be readily collected there.
Frequently a coral listed as rare was the only specimen

of that kind seen in many hours of searching and may
have been the only relict or new colony of its type in
the Islands. The number of species found increases with
the time spent searching, the astuteness of the
collector, his purpose in collecting and where he
happens to collect. I was primarily looking for certain
g8enera and must certainly have overlooked species of
other genera which were not my main concern.

I accept responsibility for all identifications
listed. Coral taxonomy as based on skeletal differences
is an imprecise science and an ongoing search for
adjunctive methods to aid in classification is in
progress. As long as this state continues, many species
determinations must necessarily be considered tentative
and this entire study can only be regarded as one in a
series.

ACKNOWLEDGMENTS

I sincerely thank the several diving partners who
collected specimens for me in Samoa and for members of
my family who supported these efforts. The following
Museum curators kindly gave me permission to study
Material under their care: Dr. P.F.S. Corneliue (British
Museum, Natural History); the late Dr. J.P. Chevalier
(Museum National d“Histoire Naturelle); Drs. D-L.
Pawson, K. Ruetzler & F.M. Bayer (United States National
Museum) and Dr. D. Devaney (Bernice P. Bishop Museum).

I am grateful to Dr. John Hoffmeister for his
Manuscripts, for encouragement and hospitality, and to
Dr. John Wells for assistance in preparation of this
paper, for his constant encouragement and for many
helpful suggestions.

Two of the Samoan visits were made under Research
grants #1372 and #1945 from the National Geographic
Society, Washington, D.C.

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ATOLL RESEARCH BULLETIN
No- 265

SOME MARINE BENTHIC ALGAE FROM CHRISTMAS ISLAND, LINE ISLANDS
BY

WILLIAM J- GILBERT

ISSUED BY
THE SMITHSONIAN INSTITUTION
WASHINGTON, D- C-, U-S-A-

SEE PEMBER noes

SOME MARINE BENTHIC ALGAE FROM CHRISTMAS ISLAND, LINE ISLANDS

by William J. Gilbert*

Published records of marine algae from the Line Islands are
restricted to Palmyra, Fanning, and Christmas Islands. Howe and
Lyon (1916), Dawson, Aleem and Halstead (1955), Dawson (1959) and
Taylor (1966b) have all listed algae from Palmyra I. More
recently a series of papers treat the benthic marine algae of
Fanning I. (DeWreede and Doty, 1970; Tsuda, Russell, and Doty,
1973; and Tsuda, 1973.) Only occasional reference to the marine
algae of Christmas I. can be found. Taylor (1966a, 1966n) cites
Turbinaria ornata (Turner) J. Ag. and Caulerpa cupressoides
(West) C. Ag-., v. mammilosa (Mont.) W.-van Bosse. Tsuda (1968)
reported the presence of Ulva fasciata Delile and Halimeda
lacunalis Taylor is mentioned from Christmas I. in the paper by
DeWreede and Doty (1970). There is mention, also, of a few
benthic algae from Cochrane Reef in a paper by Helfrich, et al.
(1968). Voucher specimens are cited for Christmas I. species
only by Taylor.

The algae reported below are from two sources: 1)
collections made by the author between June 19 and 23, 1963, who
accompanied a group led by Philip Helfrich that was working on
ciguatera fish poisoning (Helfrich, et al., (1968) at Christmas
Island and 2) some miscellaneous collections provided through the

kindness of Dr. Maxwell S. Doty, University of Hawaii.

*Department of Biology, Albion College, Albion, Michigan 49224

Manuscript received Feb. 1979 - Eds.

SPECIES LISTING

Except where otherwise noted, collection numbers are those
of Gilbert”s 1963 collections.

DIVISION CYANOPHYTA

Lyngbya majuscula (Dillw.) Harvey ex Gomont
63025, common on reef flat, Commissioner”s Reef, London, 20
Vil L963"

DIVISION CHLOROPHYTA

Acetabularia mobii Solms-Laubach
63008, on corals, Cochrane Reef, Londom, 19 VI 1963.

Boodlea composita (Harvey) Brand
Doty 20050, N.-E. Point of Christmas Island, 3) Vi 62%

Bryopsis pennata Lam.
63009, on coral, Cochrane Reef, London, 19 VI 63.

Caulerpa racemosa (Forsskal) J. Ag.
63028, in holes of coral along surge channels,
Commissioner”~s Reef, London, 20 VI 1963.

Caulerpa racemosa (Forsskal) J.Ag. var. exigua (W.-van Bosse)
Eubank 63046 and 63047, Commissioner”~s Reef, London, 22 VI
1963. This material was in the drift in large, tightly
packed, matted clumps.

Caulerpa racemosa (Forsskal) J.Ag. var. peltata (Lam.) Eubank
63013, Cochrane Reef, London, 19 VI 1963.

Caulerpa serrulata (Forsskal) J. Ag. emend Bégrg.
63048, in drift, Commissioner~s Reef, London, 22 VI 1963;
CRL 2807.3, on shore, west side of lagoon above London, 24
XI 1964; Doty 26700, East London, 26 IV 1977, coll. Sapayani
Adjak.

Caulerpa urvilliana Mont.
63019, on reef, main USA Camp, 20 VI, 1963; 63051, abundant
on reef flat near Poland Village, 23 VI 1963; Doty 18981,
seaward reef flats off “L~ site, 16 V 1962, coldo eRe.
Palumbo; Doty 18982, N.E. Point of Christmas Island, 3 VI
1962; CRL 2802.1, west reef, 1/2 mile north of London, in
shallows but covered at low tide, 23 XI 1964; Doty 20014.

Caulerpa webbiana Mont.
CRL 2782.5, north reef near airport, from exposed reef rocks
subject to wave battering, 23 XI 1964.

Cladophora spp.

Doty 20026, 16 V 1962, coll. R.F. Palumbo. The material
consists of a mixture of two species.

Cladophoropsis sundanensis Reinbold

63057, on vertical walls of small tide pools, reef flat, Bay
of Wrecks, 23 VI 1963.

Codium sp.

CRL 2781.1, north reef, found in drift, 23 XI 1964. The
Material is very close to C. edule Silva, the thallus
consisting of cylindrical anastamosing branches, 2-3 mm
diam., more or less matted and prostrate, with utricles
simple, not forming secondary utricles, and well within the
size range of C. edule. There was no evidence of
gametangia.

Derbesia minima W.-van Bosse

63016, attached to iron plates of scow, London, 20 VI 1963;
63026, Commissioner~s Reef, London, 20 VI 1963.

Dictyosphaeria setchellii Bérg.
63002, in drift, main U.S.A. Camp, 19 VI 1963; 63052, on
reef, near Poland Village 23 VI 1963; 63058, on reef flat,
Bay of Wrecks, 23 VI 1963; Doty 18970.

Enteromorpha lingulata J. Ag.
63022, attached to corals, Commissioner”s Reef, London, 20
VI 1963; 63050, in small tide pool near the Royal Navy Dock,
London, 22 VI 1963.

Enteromorpha clathrata (Roth) Greville
63010, on coral, Cochrane Reef, London, 19 VI 1963.

Halimeda fragilis Taylor

63004, in drift, main U.S.A. Camp, 19 VI 1963; 63053, on
reef flat, Poland Village 23 VI 1963; Doty 18977, N.E. Point
of Christmas Island, 3 VI 1962; Doty 18989, ~16 V 1962,
coll. Ralph F. Palumbo.

Halimeda gracilis Harvey ex J. Ag.

63001, in drift, main U.S.A. Camp, 1963; 63012, Cochrane
Reef London, 19 VI 1963.

Halimeda lacunalis MTaylor

63006, in drift, main U.S.A. Camp, 19) Vi 19635 oS 02Z0rmon
reef, main U.S.A. Camp, 20 Vi 1963.

Valonia fastigiata Harvey
63021, in drift, Commissioner”s Reef, London, 20 VI 1963;
CRL 2782.1, forming mats over exposed reef rocks, subject to
wave battering, north reef near airport, 23 XI 1964; Doty
20010.

Ulva fasciata Delile

63018, attached to iron plates of scow, London, 20 VI 1963;
Doty 26702, Southeast Point, 7 V 1977, coll. Sapayani Adjak;
Doty 28411, in Lagoon, E. of London, 16 LV 1977, couse
Sapayani Adjak; CRL 2803, beach reef, 1/2 mile north of
London, 23 x1 L964.
PHAEOPHYTA
Dictyota friabilis Setchell
63014, on coral, Cochrane Reef, London, 19 VI 1963.
Ectocarpus indicus Sonder
63024, Commissioner”’s Reef. London, 20 VI 1963.

Lobophora variegata (Lam.) Womersley

63011, on coral, Cochrane Reef, London, 19 VI 1963; 63022,
attached to corals, Commissioner”’s Reef, London, 20 VI 1963.

Turbinaria ornata €Lurner) sina.

63023A, forming dense growth on reef flat, main U.S.A.Camp,
20 5Viv1963-

RHODOPHYTA
Acanthophora spicifera J. Ag.

Doty 28409, lagoon, E. of London, 16 IV 1977, coll. Sapayan?
Adjak.

Acrochaetium gracile Bérg.

63049, epiphytic on Turbinaria, Cochrane Reef, 22 VI 1963.

Ceramium sp.

64027, scraped from iron plates of scow, London, 20 VI
1963.

Pterocladia capitlacea (Gmelin) Bornet
63056, Reef flat near Poland Village, 23 VI 1963.
LITERATURE CITED

Bérgesen, F. 1940. Some marine algae from Mauritius I.
Chlorophyceae. Det. Kgl. Danske Videnskabernes Selskab.
Biologiske Meddelelser 15(4): 3-81, 3 pls.

Dawson E. Yale 1959. Changes in Palmyra Atoll and its vegetation
through the activities of man, 1913-1958. Pacific
Naturalist 1(2): 1-52.

Dawson, E. Yale, A.A. Aleem, and Bruce W. Halstead. 1955.
Marine algae from Palmyra Island with special reference to
the feeding habits and toxicology of reef fishes. Allan
Hancock Foundation Publications, Occasional Paper No. 17:
1-39.

DeWreede, Robert and Maxwell S. Doty. 1970. Phycological
introduction to Fanning Atoll. IN Fanning Island
Expedition, January 1970. Hawaii Inst. Geophysics, Univ. of
Hawaii, HIG-70-23.

Helfrich, Philip, Twesukdi Piyakarnchana, and Phillip S. Miles.
1968. Ciguatera fish poisoning I. The ecology of ciguateric
reef fishes in the Line Islands. Occasional Papers of
Bernice P. Bishop Museum 23(14): 305-382.

Howe, M.A. and H.-L. Lyon. 1916. Algae. IN J.-F. Rock, Palmyra
Island with a description of its flora. (Privately
published in Honolulu, printed at Honolulu Star Bulletin,
Ltd.)

Taylor, W-.R. 1966a. Notes on Indo-Pacific Turbinarias.
Hydrobiologia 28:91-100.

1966b. Records of Asian and western Pacific marine algae,
particularly from Indonesia and the Philippines. Pac.Sci.
20(3):342-359.

Tsuda, Roy T. 1968. Distribution of Ulva (Chlorophyta) on
Pacific Islands. Micronesica 4: 365-368.

1973. Functional group analysis of the marine benthic algae
in Fanning Lagoon, Line Islands. IN Fanning Island
Expedition, July and August, 1972. Hawaii Inst. Geophysics,
Univ. Hawaii, HIG-73-13.

Tsuda, Roy T., Dennis J. Russell and Maxwell S. Doty. 1973.
Checklist of the marine benthic algae from Fanning Atoll,
Line Islands. IN Fanning Island Expedition, July and
August, 1972. Hawaii Inst. Geophysics, Univ. Hawaii,
JINKS 7/SsS als} c

ATOLL RESEARCH BULLETIN
No- 266

AN ACCOUNT OF THE VEGETATION OF KAVARATTI ISLAND, LACCADIVES

P. SIVADAS, B- NARAYANAN AND K- SIVAPRASAD

ISSUED BY

THE SMITHSONIAN INSTITUTION
WASHINGTON, D- C-, U-S-A-

SEPTEMBER 1983

MANGALORE

CALICUT

SS Kavaratti

0
Kalpeni : A
COCHIN !9

Figure 1. Location map of Kavaratti Island in relation to
Indian coast line.

AN ACCOUNT OF THE VEGETATION OF KAVARATTI ISLAND,
LACCADIVES

By P. Sivadas! 3, Narayanan! and xk. Sivaprasad-

The Laccadive archipelago, consisting of about 20
islands and separated from the Indian peninsula by
about a 290 kilometre stretch of sea, offers a unique
ground to study the insular flora. A few attempts have
been made to describe the flora of these islands in
general (Gardiner, 1906; Prain, 1890-94). However, the
occurrence and distribution of the plant species and
the ecological variations exhibited by them, if any,
have hitherto not been studied in these islands. As a
prelude to such a comparison, the distribution of the
plants of individual islands is being studied. A short
account of the climatic conditions and soil chemistry
of Kavaratti Island is mentioned before describing its
flora.

Kavaratti, Headquarters of the Union Territory of
Lakshadweep (Laccadives), lies on a NE-SW axis at
10°33°N latitude and 72°36°E longitude (Fig. 1).

The length of the island is 5.82 km and the maximum
width is 1.53 km, the toal area is 3.63 sq. km. The
island has an extensive lagoon on the western side
which is separated from the sea by a coral reef.

TRegional Centre, National Institute of Oceanography,
Cochin-682018, India.

2Research Fellow, Indian National Science Academy
Research Scheme. Present Address: Kerala Fisheries
Corporation, Cochin-682031, India.

Manuscript received January 1981--Eds.

CLIMATE

Kavaratti has a humid tropical climate. The
annual minimum temperature varies from 2216 lout Omens
while the annual maximum temperature varies from 29.¥
tor 32s6 Cs December-January are the coolest months
while April-May are the hottest. The island has the
benefit of both SW and NE monsoons. The SW monsoon is
much more severe, characterized by heavy gales and
winds. The NE monsoon is milder. The total number of
rainy days varies from 65 to 85. The average monthly
rainfall for the years 1970 to 1975 varies from 130 to
190 mn.

SOIL

The soil is formed by the dead, disintegrated and
weathered skeletons of corals. It is estimated to
contain 95% calcium carbonate in the form of aragonite.
The pH of the soil varies from 8 to 8.4. Percentage of
organic carbon is 1 to 1.4. Available phosphorus is
present at the rate of 98.8 kg/Ha and available potash
at the rate of 65 kg/Ha. The nitrification of the soil
is affected by the alkalinity to a considerable extent.
The soil is of an open character and possesses good
drainage and aeration.

VEGETATION

During the present study, emphasis was given to
determining the plant species represented in the
island. The plants are taxonomically arranged
according to the Bentham and Hooker system. For the
convenience of collection and recording, the whole
island is arbitrarily divided into four zones, and the
distributions of some of the plants have been shown in
Figs. 2 and 3.

Kavaratti has a good vegetation cover. The
northern portion of the island is inhabited and plants
like Musa paradisiaca, Colocasia esculenta, Carica
papaya, Amaranthus sp., etc., are cultivated here.
Moringa oleifera, Artocarpus altilis and Terminalia
catappa are seen growing wild in zones 1 and 2. The
southern end of the island has a shrub jungle
consisting of plants like Scaevola sericea, Premna
obtusifolia, Calophyllum inophyllum, Pandanus
odoratissimus, Morinda citrifolia, etc. Trees like
Casuarina equisetifolia, Zizyphus mauritiana and

Thespesia populnea are distributed throughout zones 1,
2 and 3. Tournefortia argentea and Pemphis acidula are
seen on the western side of the island in zones 3 and
4. Ficus bengalensis does not seem to adhere to any

specific pattern of distribution and is seen at random
in the island.

The ground vegetation consists of plants like
Spinifex littoreus, Argemone mexican, Ipomoea
pes-caprae, Aerva lanata, Alysicarpus monilifer,
Evolvulus alsinoides, Commelina bengalensis, etc.
Distribution of Spinifex littoreus is restricted to
certain areas in zones 1, 3 and 4. Zones 1 and 4 have
an extensive coverage of herbs like Kyllinga
monocephala and Setari italic . Blumea membranace is
seen distributed in zones 3 and 4. There is an
extensive growth of Stachytarpheta indic in zones 2
and 3 especially in front of the Secretariat buildings.
Lantana camara and Bougainvillea spectabilis are two
plants occurring throughout the island. The Gandhi
Centenary Park has a number of recently introduced
garden plants like Codiaeum variegatum, Ipomoea
quamoclit, Hibiscus rosa-sinensis, Cosmos sulphureus,
Nerium indicum, Pedilanthus tithymaloides, etc.

The Lakshadweep administration is maintaining an
agricultural farm where a number of common vegetables
like Hibiscus esculentus, Solanum melongena, Capsicum
minimum, Trichosanthes cucumerina, Cucumis sativus,
etc. are grown. Eucalyptus sp. is now grown in this
farm as a trial.

It appears that an attempt was made to cultivate
Oryza sativa in this island long ago. The information
collected from the islanders corroborates well the
evidence of soil removed from certain areas in the
island to make paddy fields. The soil thus removed was
dumped on other portions of the island, thus making
artificial sand dunes. However, paddy cultivation here
appears to have been unsuccessful. This may be because
of the high alkalinity of the soil and the
unavailability of sufficient fresh water for
irrigation.

Cocos nucifera is the main plantation crop. Two
varieties are grown; the common tall variety and the
endemic micro-variety. The micro-variety is small and
is under 5” or 6° in height. The yield is very high
though the size of the fruit is comparatively small.
The ~Copra” obtained from these coconuts contains a
high level of oil when compared to the ordinary

variety. Some of the islanders are cultivating Piper
nigrum and Manihot esculenta in their private lands.
Piper betle and Areca catechu are the two other common
plants grown by the islanders.

There is a sea grass bed consisting of Thalassia
hemprichii and Syringodium isoetifolium on the bottom
of the lagoon, growing from about low water neap tide
and continuing out to a distance of about 100 mn. In
certain parts it extends even farther than 100 m
forming smaller patches in the lagoon. Usually a huge
bulk of dead Thalassia hemprichii is washed ashore and
it is possible that it also contributes greatly to the
particulate organic carbon of the lagoon.

A total of one hundred and seventeen terrestrial
plants have been collected from the 3.629 sq. km island
alone. Forty-eight families of angiosperms are
represented here. However, this investigation has not
revealed any endemic forms.

New plants are being introduced constantly and the
human influence is quite visible. Plants like
Alysicarpus monilifer, Crotalaria fysonii, Codiaeum
variegatum, Ipomoea quamoclit seem to have been
introduced since they are not recorded by Gardiner
(1906). Following is the complete list of plants
collected from Karawatti Island:

PAPAVERACEAE
EF

Argemone mexicana L. H 001 » Zl, 22.
CAPPARIDACEAE

Cleome viscosa L. TSI SZAGY Zi2ke
PORTULACACEAE

Portulaca oleracea L. IER ewAIL PAD AS) AAS
GUTTIFERAE

Calophyllum inophyllum L. Si) Zilky) Lilt eis eect.
MALVACEAE

Abutilon indicum (L.) Sweet Ish WAR AAT (Gs}o

Gossypium barbadense L. Si? UZ a Ziek naar

* H - Herbarium kept in Regional Centre, N10. (No
standard symbol available).
ES -sidentified on: sight.

Zi= Zone.

# - Names followed by # have been substituted by the
editors to correspond to recent changes or in some cases
for consistency with what seems the best current usage.
Hence they are not the responsibility of the author and
his advisors. It is with some hesitation that we
publish the numerous sight records that are not
supported by speciméns. F.R.F., ed.

Hibiscus rosa-sinensis L, tS, AB
eee, Osos iene rs

Hibiscus esculentus L. tS, Z25 Be
Thespesia populnea (L.) Sol. kl OOS ZL, 225 243,
ex Correa

TILIACEAE

Corchorus trilocularis L. H 004, Z2, Z4.

Corchorus capsularis L. PS5 23), 24s.
RUTACEAE

Citrus grandis (L.) 1B, Bile

Osbeck #

Citrus medica L. IS 5 Allo
MELIACEAE

Azadirachta indica A. Juss. El M05, Bi, 42,5 Bso
RHAMNACEAE

Zizyphus mauritiana Lamk. kl @0@GO, Ail, Z2c

Zizyphus sp. El O00, Bio Zao
VITACEAE

Leea sp. H 008, Z2.
SAPINDACEAE

Dodonaea viscosa L. S85 Z36 Bho

Cardiospermum halicacabum L. US, 42, 435 B&o

: LEGUMINOSAE

Alysicarpus monilifer DC. H 009, Zl, Z2, Z4.

Crotalaria fysonii Dunn. US, Blo Zo, BZSo

Crotalaria verrucosa L. H O10, Z2.

Crotalaria retusa L. H 012, Z2.

Cassia occidentalis L. US, 4aApy BSo

Cassia tora L. USp Zh, sso

Cassia sp. H 013, Z2, 23.

Clitoria ternatea L. IS, Zils, B20

Desmodium gangeticum (ih. )D@. US, BZiy Zo sho

Indigofera tinctoria L. ll MIA, ZA, BASso

Phaseolus sp. Bl @IS, ABs, Asso

Tephrosia sp. H 016, Z2, Z3.
COMBRETACEAE

Terminalia catappa L. Bl MU, Al, Bo
MYRTACEAE

Psidium guajava L. Is, 22.
LYTHRACEAE

Pemphis acidula Forst. WS, GZ, Bho
CARICACEAE

Carica papaya L. US, Bly ZB, ZSo
CUCURBITACEAE

Trichosanthes cucumerina L. Bl OLB, Aly ZA, Bo

Cucumis sativus L. UA, ly Ao

Coccinia grandis (L.) Voight BL @1Y), Bil, Z25 BSc

RUBIACEAE
Morinda citrifolia L. TeSys. Bais
Hedyotis umbellata (L.) Lamk. H 020,
COMPOSITAE
Blumea membranacea DC HeaOi2ee5
Cosmos sulphureus Cav. HerOy2:25,
Spilanthes calva DC. HOF,
Veronia cinerea (L.) Less. HMO2;4;;
Tridax procumbens lL. HiesO:225y5
Zinnia sp. HO) 26);
GOODENLIACEAE
Scaevola sericea Vahl # HimOl27a5
SAPOTACEAE
Chrysophyllum cainito L. TES Zi2te
Manilkara zapota (L.)
P.V. Royen # Sy, AY
APOCYNACEAE
Neisosperma oppositifolia
(Lamrk.) Fosberg & Sachet # 1st OWE} 5
Parsonsia alboflavescens
(Dennst.) Mabberly Hy O29;5
Nerium oleander var. indicum
(Mill.) Deg. # H 030,
ASCLEPIADACEAE
Calotropis gigantea R. Br. Sze
BORAGINACEAE
Tournefortia argentea L.f. HOS;
CONVOLVULACEAE
Ipomoea pes-caprae (L.) Sweet IERYS 47) 5
Ipomoea macrantha R. & S. # Hi 103/275
Evolvulvus alsinoides L. HOSS
Ipomoea quamoclit L. H 034,
Cuscuta reflexa Roxb. HS) Zar
SOLANACEAE
Capsicum minimum Roxb. IER A 4740
Capsicum frutescens L. WS Zizi
Datura stramonium L. HesOSions
Solanum lycopersicum L. # INS 35) Lilie
Solanum melongena L. Itsy 5 APA
BIGNONIACEAE
Tecoma stans (L.)- H.B. & K. H 036,
ACANTHACEAE
Andrographis sp. HieOi3\7,
Justicia procumbens L. IE All 5

Ay als fk

73. ies
Zits
yy go
70) a ade
ZB
Zhe

Z4.
Z4.
Z4.

Z4.

22.

Zs. Zar

AG SNORS

Z2.

D354 Zoe
Zoe
Z3),
Pl
Bo) 6

Zax.
Z4.

yd ese Ae

Tene (Gaye

Z2e, ALO

Zien Zioes
22.

Z3 eZ0e
23) su Zee

VERBENACEAE

Clerodendrum inerme (L.) Gaertn. H 038, Z2.
Lantana camara L. US iA, VAD Ay. Ale
Premna obtusifolia R. Br. kl O89, Adc
Stachytarpheta indica Vahl kl O40, 42, Zo
Lippia nodiflora (L.) Rich. H 041, Z2, Z4.
LABIATAE
Ocimum sanctum L. MO5 420
Anisomeles indica 0. Ktze. Bl @42,5, 45, GBs BSc
NYCTAGINACEAE
Boerhavia diffusa L. Bl O43, Bil, #Ads43o
Bougainvillea spectabilis
Willd.? 85 Z25 Bo
AMARANTHACEAE
Achyranthes aspera L. ParmrarMOMa* Zl 70. 27.35.
Amaranthus gangeticus L. Is
Amaranthus spinosus L. Is
Amaranthus caudatus L. Is
Amaranthus viridis L. Is
Aerva lanata (L.) Juss. ll @45, Zl, 425 AS 54Bc
Celosia argentea L. WS 5425 Bo
PIPERACEAE
Piper nigrum L. IS, Bh, ZLo
Piper betle L. Is, Zl, Z2.
EUPHORBIACEAE
Acalypha indica L. H 046, Z2, Z3.
Codiaeum variegatum L. H 047, Z2.
Ricinus communis L. H 048, Zl.
Pedilanthus tithymaloides (L.)
Poit. H 049, Z2, Z3.
Emblica officinalis Gaertn. H 050, Z2.
Manihot esculenta Crantz HS5 ZAllo
Euphorbia tirucalli L. Is, Z3.
Euphorbia rosea Retz US, 4225 435 Abo
Euphorbia thymifolia L. 185 425 G35 Bho
Euphorbia hirta L. WS5 Bly GZG®s Zp B&o
MORACEAE
Artocarpus altilis (Park.)
Fosberg S85 Zly5 Z2ho
Ficus religiosa L. RS>p Zly ZG, Z_ Bho
Ficus bengalensis L. WS, Zils 425 Zc
URTICACEAE
Pouzolzia zeylanica(L.)Benn. EOS, Zi,» Z2, Bo
CASUARINACEAE
Casuarina equisetifolia L. HO52, Zl, 22, Z3.
CANNACEAE
Canna indica L. ES), 23%
MUSACEAE
Musa paradisiaca L. 35 Bil, ZG, BZSo

AMARYLLIDACEAE
Agave sp. UEC AZ2 5 WAS! 0
DIOSCOREACEAE
Dioscorea alata L. ES5, Zl 225 ere
LILIACEAE
Gloriosa superba L. HOSS pZiceecior
Rhoeo spathacea (Sw.) Stearn ley RAPA 5 745} 6
Asparagus racemosus Willd. S64 64S} c
COMMELINACEAE
Commelina benghalensis L. HO54 5 Zl, (22h corre
a ee? eS rE ARECACEAE
Areca catechul L. ST Zale
Cocos nucifera L. MSiy (Lilie Liles orem
PANDANACEAE
Pandanus odoratissimus L.f. Is, zZ4.
ARACEAE
Alocasia macrorrhiza (L.)
Schott Mes Ally BA
Colocasia esculenta (L.) Schott MES 5 Ad 5 ABS
CYPERACEAE
Cyperus kyllingia Endl. # 15) ALG As AS5 Bho
GRAMINEAE
Spiniflex littoreus Merr. 1b AIR 4S) 5 Alc
Saccharum officinarum L. IGS YH Z474c
Setaria italica Beauv. i ils AAAS Bes Aho
ACKNOWLEDGMENTS

The authors would like to express their
gratefulness to (the late) Dr. N. K. Panikkar, former
Director, National Institute of Oceanography, Goa,
India, for the interest he took in this investigation,
to Dr. S. Z. Quasim and Dr. T.S.S. Rao for their help.
They would like to thank Prof. M. C. John, Head of the
Department of Botany, C.M.S.College, Kottayam, India,
and Mr. M. K. Menon, Taxonomy Division, Kerala Forest
Institute, Peechi, Trichur, India, for the help rendered
to identify some of the plants. This work was done
during the tenure of a project sponsored by the Indian
National Science Academy (INSA) and one of us (K.S.P.)
is thankful for the award of the fellowship.

REFERENCES

Gardiner, J.-S. 1906. The fauna and geography of the
Maldive and Laccadive Archipelagoes, being the
account of the work carried out and of collections
made by an expedition during the years 1899 and
1900, Vol. 2, Cambridge: University Press.

Prain, D- 1890. A list of Laccadive plants. Sc. Mem.
Med. Off. Army India, 5: 47-70.

1892-94. Botany of the Laccadives, being natural
history notes from H.M.I.M. Survey Steamer
“Investigator”...J. Bombay Nat. Hist. Soc., 7:
268-95; 1892; 8: 57-86, 1893; 488, 1894.
(Reprinted in Memo. and Memor. 301-89, 1894.)

?
?
?
?
2
?
?
?
?
2
?
?
P]
)
?
?
?
2
?

+ BLUMEA MEMBRANACEA

e SPINIFEX LITTOREUS

° KYLLINGA MONOCEPHALA

ZB SEA GRASS BED

1 KM

Figure 2. Kavaratti Island. Diagrammatic representation of the
distribution of some terrestrial plants.

a
a )
cy
,

)
»)
?
)
P)
?
)
?
Ps
P)
P)
Pp)

( MORINGA OLEIFERA

t PEMPHIS ACIDULA

Figure 3. Kavaratti Island. Diagrammatic representation of the
distribution of some terrestrial plants.

Plate 1. Extensive bed of Thalassia on the intertidal area

- i A nt eed ities SS a

Plate 2. Huge bulk of dead Thalassia washed ashore

Plate 4. Pemphis acidula on the lagoon side of the beach

ATOLL RESEARCH BULLETIN
No- 267

AVIFAUNA OF THE SOUTHWEST ISLANDS OF PALAU
BY

JOHN ENGBRING

ISSUED BY

THE SMITHSONIAN INSTITUTION
WASHINGTON, D- C-, U-S-A.-

SHA wsals aes)

‘Guam

: i bebelcaon
Soe eee Bk eer c ‘
Qs3 Korér, @;

7 ae

Pee Won
s a
Yew!

Angaure - Peleliu

Sonsorol

-Pulo Anna N

Merir

PALAU

Major archipelago

and Southwest Islands

0 50 100

Figure 1. Major islands of Palau, including the six Southwest Islands.

AVIFAUNA OF THE SOUTHWEST ISLANDS OF PALAU

by John Hagieiae

INTRODUCTION

The Palau Archipelago (7° 20' N, 134° 30' E) lies at the
westernmost edge of the Pacific, just north of the equator and nearly
equidistant from New Guinea to the south, the Philippines to the west,
and Guam to the northeast (Figure 1). As a part of Micronesia, Palau
became a United States Trust Territory following World War II. The
government is now in a transitional state, and is shifting from a trust
to independent status.

The Southwest Islands of Palau are composed of six tiny islands,
each less than 2 km?, extending 600 km southwest of the capital, Koror.
The islands are Sonsorol and Fanna (the Sonsorol Islands), Pulo Anna,
Merir, Tobi, and Helen. Other place names for the islands, and areas,
are listed in Bryan (1971). Tobi and Helen, the southernmost of the
group, lie only 400 km north of western New Guinea. All of the islands
are of low elevation, with a substrate of coralline rubble interspersed
with sandy areas. Most of the islands harbor minor deposits of
phosphate, much of which was removed before World War II during the
Japanese administration (Hutchinson 1950). The islands support
relatively verdant forests, with coconut (Cocos nucifera) being the
dominant species on most. Other trees include Artocarpus spp., Ficus
spp-, Calophyllum inophyllum, Barringtonia asiatica, Pandanus sp.,
Tournefortia argentea, Scaevola taccada, Neisosperma oppositifolia, and
Eugenia javanica. Other than Helen, which has a large encircling outer
reef and an inner lagoon, the islands are surrounded by fringing reefs
that generally extend 200-600 m from land before dropping off steeply
into ocean depths. These fringing reefs form rocky flats that are
exposed at low tides.

Politically, the islands are part of Palau, but the residents are
culturally distinct and speak a separate language. Historically, all
the islands except Helen have been inhabited by Micronesians related to
those of other outer islands in the Western Carolines (Eilers 1935,
1936). Though densely populated at one time, only a few families reside

} U.S. Fish and Wildlife Service, Honolulu, Hawaii
Manuscript received July 1981 -- Eds.

there today. The economy remains at a subsistence level, with copra
the nearly sole source of income; other minor trade items include
coconut syrup, shells, and handicrafts. On Helen, sea cucumbers are
also collected, dried, and exported for consumption in the Orient.
Contact with the outside world is made every 3-4 months by ship from
Koror. This "field trip ship" stops for 1-2 days at each island,
purchases copra, delivers staples, and fulfills other needs of the
residents.

The avifauna of the Southwest Islands is undescribed, although
large seabird colonies are present on Fanna and Helen. From Helen,
Owen (1977a) recorded the Great Frigatebird (Fregata minor) and Lesser
Frigatebird (Fregata ariel) and Yamashina (1940) recorded the Sooty
Tern (Sterna Fuscata) and Crested Tern (Thalasseus bergii). Two
unpublished reports, a checklist (Owen 1977b) and a field guide
(Engbring 1981), give distribution and relative abundance of Southwest
Island seabirds. Outside of these references little else is available
on the birds of the region.

METHODS

The following report is based on two trips I made to the islands
while working in Palau as a Smithsonian-Peace Corps Volunteer. One
trip was in the fall from 9-20 November 1977, and one was in the spring
from 18-26 May 1979 ("spring" and "fall" in this report refer to
seasons of the Northern Hemisphere). During each of these trips the
ship generally spent 1-2 days at each island, and I spent several hours
per day on shore making general observations. Seabirds were also
frequently recorded from the ship as it waited a few hundred meters
from the outer edge of the reef. I spent a total of 6 daylight hours
on Fanna, 14 on Sonsorol, 15 on Pulo Anna, 8 on Merir, 26 on Tobi, and
19 on Helen. Offshore (within sight of land) I spent 6 daylight hours
at Fanna, 22 at Sonsorol, 8 at Pulo Anna, 6 at Merir, 16 at Tobi, and
10 at Helen. At Helen I stayed one night on shore, when I was able to
observe the large number of birds returning to roost at dusk. Whenever
possible, I questioned the local residents regarding avifauna.

Additional information was contributed by Warren King,
Dennis Puleston, and Thomas Ritchie, who spent 18 and 19 October 1979
on Helen and Merir while traveling on the M.S. Lindblad Explorer; by
Greg Bright, who visited the region from 24 November to 2 December
1978; and by Robert Owen, who spent 30 years in Palau and visited the
Southwest Islands on several occasions.

THE ISLANDS
Sonsorol) Tsillands;) 5au202 NF els2e shee

Because of their proximity, two islands are included in this
group, Sonsorol (136 ha), which has about 25 residents, and Fanna (54

ha), an uninhabited island located 2 km north of Sonsorol. Residents
of Sonsorol regard Fanna as a reserve, but make occasional foraging
expeditions by dugout canoe to Fanna for fish, coconut crabs, and
birds. Both islands are covered by a forest of tall trees with a
relatively well-formed canopy and a moderately dense understory.
Several huge, stately Ficus and Artocarpus grow on Fanna.

Fanna harbors spectacular seabird colonies. The Black Noddy
(Anous minutus) and Red-footed Booby (Sula sula) nest in immense
numbers. Although less plentiful, White Terns (Gygis alba) are also
abundant. In Palau, Fanna is the only known nesting site for Great
Frigatebirds, and possibly Lesser Frigatebirds as well. Also resident
are the Brown Noddy (Anous stolidus), and a few Brown Boobies (Sula
leucogaster). Only four seabirds are known to reside on Sonsorol, none
in profuse numbers. In order of abundance these are the Brown Noddy,
the White Tern, the Black Noddy, and the White-tailed Tropicbird
(Phaethon lepturus). Fruit bats (Pteropus sp.) are conspicuous
arboreal denizens on both Sonsorol and Fanna, but are not seen on the
other Southwest Islands.

Pulo Anna; 4° 40' N, 131° 58' E

Pulo Anna (50 ha) is covered by large trees, with a relatively
open understory. A shallow, open, brackish swamp, approximately 200 by
200 m, is located in the center of the island. The swamp is littered
with decaying logs, remnants of mangrove trees that were cleared by
U.S. military forces after World War II during a mosquito control
program. Water level fluctuates with the tides, though there is no
above-ground connection with the ocean. Approximately 20 or fewer
people live on the island.

Resident seabirds include an abundance of Brown Noddies and White
Terns, and lesser numbers of White-tailed Tropicbirds and Black
Noddies. Great Frigatebirds commonly soar above the island, but are
not known to nest on Pulo Anna. Migratory shorebirds regularly use the
swamp, which provides an excellent resting and feeding area despite its
limited size.

Meri 4 LOY ON. 1325 19

Merir (90 ha) is moderately elongated, just over 2 km from the
northern to southern tip. A typhoon in the mid-1960's destroyed much
of the vegetation, and a thick growth of medium-sized trees has since
grown. Numerous large, dead trees still extend above the post-typhoon
canopy. A shallow, heavily overgrown swamp is present on the southern,
interior portion of the island, but because it is overgrown by shrubs,
few shorebirds utilize it. Merir is riddled with mosquitos, and this,
along with the dense understory, makes the interior generally
inhospitable. In recent years only one family of fewer than ten people
has resided on the island.

Brown Noddies are the most abundant species on the island, with
lesser numbers of White Terns and White-tailed Tropicbirds. King et
al. (1980) recorded Black Noddies in moderate numbers in 1979.
Frigatebirds, mostly Great but a few Lesser, regularly soar above and
roost on the island, but are not known to nest.

fopr: 3 Of NS isl ti se

With about 70 people, Tobi (60 ha) is the most heavily populated
of all the Southwest Islands. Much of the triangular island is covered
with tall coconut groves that are relatively well manicured and have
open understories. A shallow, centrally located swamp, which is partly
planted with taro (Colocasia esculenta), is largely the result of
pre-war phosphate mining by the Japanese. The small amount of open
water provides good but limited habitat for migratory shorebirds.
Scattered throughout the swamp area are large earthen mounds, also the
result of mining activities. The limited amount of native forest on
the island contains several massive specimens of Ficus and Calophyllum.

Seabird densities on Tobi are similar to those on Pulo Anna, with
healthy populations of Brown Noddies and White Terns, and many fewer
White-tailed Tropicbirds and Black Noddies. Great Frigatebirds are
commonly seen soaring overhead.

Helens: 22.2759") Nw fl S1ier49 "eer

Unlike the other Southwest Islands, Helen is an atoll and consists
of a large reef that encircles an open lagoon (100 km?). The only dry
land, which is at the northern tip of the reef, is low and small (ap-
proximately 25 ha), and is mostly sand. At low tide, conspicuous sand
spits extend to the north and south of the crescent shaped island.
Though the island was historically uninhabited, residents of Tobi,
nearly 75 km away, made occasional forays to Helen. When this study
was made, fewer than ten people lived on Helen, but the population
varies depending on the number of "visitors" from Tobi or other
Southwest Islands. The vegetation consists almost exclusively of large
coconut trees, medium-sized Tournefortia trees, and a few sparse clumps
of grass.

Impressive numbers of seabirds reside on Helen, and seabird
density is greater here than on any other Southwest Island. The superb
quality of Helen as a nesting site is probably due to its isolation,
its beaches which are protected from large waves by the outer reef, and
its lagoon which supplies an abundant food supply. There are sizable
colonies of Crested Terns, Black Noddies, Sooty Terns, and Red-footed
Boobies, and moderate numbers of Brown Boobies and Black-naped Terns
(Sterna sumatrana). White Terns recently began nesting on Helen in
small numbers. Both Great and Lesser Frigatebirds commonly soar near
the island and roost in the tall coconut trees. Neither species is
thought to nest regularly on Helen, but a male Lesser Frigatebird was
recorded on a nest in 1969 (Owen 1977).

AVIFAUNA

Forty-seven species of birds have been recorded from the Southwest
Islands (Table 1), of which 14 are resident and 33 are migrant or
vagrant. Four additional genera have been recorded that are not
identified to species (Table 1). Out of the 14 resident species, 11
are seabirds and three are land birds. The 11 species of resident
seabirds represent four families: Phaethontidae (one species), Sulidae
(two species), Fregatidae (two species), and Laridae (six species).
Conspicuously absent is the family Procellariidae. Most nonresidents
are migratory shorebirds. Several recent new bird records for Palau
(Engbring and Owen 1981, King et al. 1980) were nonresidents recorded
from the Southwest Islands. These are the Red-tailed Tropicbird,
Masked Booby, Chinese Goshawk, Bush Hen, Brown Shrike, and Lanceolated
Warbler.

Nonresident Birds

Though a number of vagrant and migratory species have been
recorded from the Southwest Islands (Table 1), the list is no doubt
incomplete. Any of the migratory species already recorded from the
Palau Archipelago (Engbring 1981, Owen 1977c) are likely to occur in
the Southwest Islands as well. The majority of migrants are shorebirds
from the Eastern Eurasian Region that are moving south during the
boreal winter; a few are birds from New Guinea or Australia that are
traveling north during the austral winter; and a small number are
probably east-west migrants from Southeast Asia, the Philippines, or
Indonesia (Baker 1951). The most common shorebirds (5-20 regularly
seen at any one time on each island during migration) include Lesser
Golden Plover, Ruddy Turnstone, Whimbrel, and Gray-tailed Tattler.
Important habitat types utilized by shorebirds include the small inland
swamps on Pulo Anna and Tobi, reef flats, and sandy beaches.

Unidentified Species

A number of birds were observed that were not positively identified:

Shearwater - Puffinus sp.: One all dark shearwater was seen about
80 km north of Sonsorol on 26 May 1979. Its size and color matched
that of the dark phase of the Wedge-tailed Shearwater, Puffinus
pacificus, but there are several all dark shearwaters in the Pacific
with which the bird could have been confused. This was the only
Procellarid that I saw in 18 days at sea.

Tattler - Heteroscelus sp.: Tattlers were regularly observed on
most of the islands. On the basis of call, I identified Gray-tailed
Tattlers on Merir and Tobi. King et al. (1980) identified Gray-tailed
Tattlers on Helen and Merir. Unidentified Tattlers could possibly be
the Wandering Tattler, Heteroscelus incanus, a migrant in Palau which
is less common than the Gray-tailed Tattler.

Table 1. Distribution and status of Southwest Island birds. Common
and scientific names follow the American Ornithologists' Union (1982)
check-list whenever possible. Other names are from Owen (1977c) and
King et al. (1975).

Status Symbols

R - Resident; nests within the Southwest Islands and is generally

present year-round. Different classes of resident birds are
indicated with lower case letters as follows:

b — Breeding species on the island; nests, eggs, or young recorded.

p - Probable nester on the island, but nests, eggs, or young not
recorded.
t - Transient; recorded near (generally within sight of) land, but

is not thought to nest on the island. May or may not roost on
the island.

Migrant; migratory species not resident in the Southwest Islands.

Vagrant; accidental occurrence of a normally non-migratory species.

Abundance Symbols
Single individual recorded on one or more occasions.
Uncommon; 2-10 birds recorded on at least one visit.
Common; 11-50 birds recorded on at least one visit.
Numerous; 50-1,000 birds recorded on at least one visit.

Abundant; over 1,000 birds recorded on at least one visit.

Island Symbols

Fanna.
Sonsorol.
Pulo Anna.
Merir.
Tobi.

Helen.

Table 1, continued

Island

Species FA SO PU ME

Shearwater genus (M) Puffinus sp.

White-tailed
Tropicbird (R) Phaethon lepturus

Red-tailed Tropicbird (M) Phaethon rubricauda

Masked Booby (V) Sula dactylatra
Brown Booby (R) Sula leucogaster
Red-footed Booby (R) Sula sula

Great Frigatebird (R) Fregata minor

Lesser Frigatebird (R) Fregata ariel
Cattle Egret (M) Bubulcus ibis

Pacific Reef Heron (R) Egretta sacra

Little Egret (M) Egretta aaemaeea.
Plumed Egret (M) Egretta intermedia
Chinese Goshawk (M) Accipiter soloensis
Red Junglefowl (R) Gallus gallus

Bush Hen (V) Amaurornis olivaceus

Black-bellied Plover (M) Pluvialis squatarola
Lesser Golden Plover (M) Pluvialis dominica

2
Mongolian Plover (M) Charadrius mongolus

Little Ringed Plover (M) Charadrius dubius

Oriental Plover (M) Charadrius meredten
Common Greenshank (M) Tringa nebularia
Wood Sandpiper (M) Tringa glareola

Gray-tailed Tattler (M) Heteroscelus brevipes

Table 1, continued

Species

Tattler genus (M)
Common Sandpiper (M)
Little Curlew (M)
Whimbrel (M)
Black-tailed Godwit (M)
Bar-tailed Godwit (M)
Ruddy Turnstone (M)
Rufous-necked Stint (M)
Stint genus (M)
Curlew Sandpiper (M)
Snipe genus (M)
Common Tern (M)
Black-naped Tern (R)
Sooty Tern (R)

Little Tern (M)
Crested Tern (R)
Brown Noddy (R)
Black Noddy (R)

White Tern (R)
Nicobar Pigeon (V)
Oriental Cuckoo (M)
Cuckoo genus (M)

Hawk-Owl genus (M)

Heteroscelus sp.

Actitis hypoleucos

Numenius minutus

Numenius phaeopus
Limosa limosa
Limosa lapponica

Arenaria interpres

Calidris eueieoiiges
Calidris sp.
Calidris ferruginea

Gallinago sp.

Sterna hirundo
Sterna sumatrana
Sterna fuscata
Sterna albifrons
Thalasseus bergii
Anous stolidus
Anous minutus
Gygis alba
Caloenas nicobarica
Cuculus saturatus
Cuculus sp.

Ninox sp.

Gray-streaked

Table 1, continued

Island
Species FA SO PU ME TO HE

Collared Kingfisher (R) Halcyon chloris

Bee-eater genus (M) Merops sp.

Dollar bird (M) Eurystomus orientalis
Barn Swallow (M) Hirundo rustica
Yellow Wagtail (M) Motacilla flava
Brown Shrike (M) Lanius cristatus

Lanceolated Warbler (M) Locustella lanceolata

Flycatcher (M) Muscicapa griseisticta

It is not certain whether the Little Egret can be separated from the
Snowy Egret (E. thula), which has not been recorded from Palau. I
Saw two white egrets wading on reef flats along the shore at Tobi on
15 November 1977. Both were alike, with narrow plumes on the nape,
black beaks, orange-yellow lores, black legs (with a greenish tinge),
and greenish-yellow toes.

The Mongolian Plover is similar to the Greater Sand Plover (C.
leschenaultii). Prior to my visit to the Southwest Islands I
regularly observed both species in Koror, Palau, and considered the

two separable on the basis of size, leg length, and leg color, among
other field traits.

Some consider this as two species, C. veredus and C. asiaticus.

The Rufous-necked Stint is similar to two other small Calidrids, the
Little Stint (C. minuta) and the Semipalmated Sandpiper (C. pusilla),
and would be difficult to separate from them in winter plumage. The
individual I observed on Helen on 22 May 1979 was entering breeding
plumage, and had an even wash of reddish color on the breast and
neck. I used this trait to separate it from the other two species,
neither of which have been recorded from Palau.

Recorded by King et al. (1980).

Snipe -,Gallinago sp.: I flushed three snipe on Tobi on
14 November 1977, and King et al. (1980) observed one on Helen on
18 October 1979. None of these individuals were identified to species,
though it is likely that one or more were Swinhoe Snipe, Gallinago
megala, the only species of snipe collected from Palau.

Stint - Calidris sp.: I observed two stints in winter plumage,
one on Helen on 13 November 1977, and one on Tobi on 17 November 1977.
These appeared to be and most likely were Rufous-necked Stints,
Calidris ruficollis. However, they could not be safely separated from
the winter plumage Little Stint, Calidris minuta, or Semipalmated
Sandpiper, Calidris pusilla, neither of which has been recorded from
Palau.

Hawk-owl - Ninox sp.: An unidentified, small brown owl was first
reported from Helen on 28 November 1978 (Bright 1978). On
18 October 1979, another owl was observed that was identified as the
Brown Hawk-Owl, Ninox scutulata (King et al. 1980). The owl was most
likely the Brown Hawk-Owl, as it is a widespread species in Southeast
Asia that migrates to the Philippines. However, there are several
other Ninox spp. that reside on nearby islands with which the Brown
Hawk-owl could conceivably be confused.

Cuckoo - Cuculus sp.: I observed one cuckoo on Tobi which was
either the Oriental Cuckoo, Cuculus saturatus, or the Common Cuckoo,
Cuculus canoris.

Bee-eater - Merops sp.: I observed a flock of eight bee-eaters on
Tobi on 21 May 1979. Tentatively these have been identified as the
Rainbowbird, Merops ornatus, an Australian species. All the birds were
in immature plumage, however, and further comparison of the Australian
species and two Philippine bee-eaters should be made.

In addition to the above unidentified birds, Bright (1978)
observed an all black bird with a long tail on Tobi on 29 November
1978. The individual was at least 36 cm long, and had dark legs, but a
lighter bill. It perched in a small tree near the edge of the swamp.
The bird was probably a male Common Koel, Eudynamys scolopacea.

Resident Land Birds

Pacific Reef Heron - Egretta sacra. The reef heron is resident on
all of the Southwest Islands, and is conspicuous as it feeds on reef
flats at low tide. The population on each island probably numbers no
more than 15-20 individuals. No nests have been recorded. Based on
its widespread insular distribution one can assume that the reef heron
is a capable overseas wanderer, but no patterns of movement are evident
in the Southwest Islands. On Helen, records indicate a variation in
population size; one bird was recorded in September 1969 (Owen, field
notes), eight birds in November 1977 (this study), three birds in May
1979 (this study), and eleven birds in October 1979 (King et al. 1980).

This population fluctuation could be due to ingress/egress,
reproduction, or simply counts of varying completeness. It is unlikely
that reef herons are overlooked on Helen, but birds may be roosting on
derelict ships on the surrounding reef, and thus missed during a count.
White and dark phase birds are represented in about equal proportions
on all the islands.

Red Junglefowl - Gallus gallus. Domestic junglefowl are regularly
heard and seen on Sonsorol, Pulo Anna, Merir, and Tobi. The species is
commonly raised by residents, and is likely to be found on any of the
Southwest Islands, particularly near villages. The species was
probably introduced by early island settlers. A few birds are probably
feral, but this is difficult to determine. Early reports indicate that
the junglefowl was valued more for its feathers, which were used for
fishing lures, than for its flesh (Johannes 1981).

Collared Kingfisher - Halcyon chloris. A few, evenly dispersed
individuals or pairs can be located on any of the Southwest Islands.
The population is estimated at 20 or fewer on each island. I assume
the species is resident, but found no nests. On Helen, only one or two
birds have been recorded at any time, and these are possibly vagrants
from other Southwest Islands, New Guinea, or Indonesia.

Resident Seabirds

Estimates of the size of nesting colonies are summarized in Table
2, and species accounts are as follows:

White-tailed Tropicbird - Phaethon lepturus. Although nowhere
abundant, individuals and small groups can be found commonly on all of
the Southwest Islands but Helen. Population size is estimated at under
50 individuals at any one time on each of the islands of occurrence.
The tropicbird's absence from Helen can probably be explained by the
limited amount of forest, which serves as nesting habitat. Though I
recorded no birds from Fanna, the species is probably resident here.
Birds were found in equal numbers in spring and fall, indicating
negligible variation in nesting season and no definite migratory
pattern. Though no nests have been recorded, the species presumably
nests in the Southwest Islands. Elsewhere in Micronesia, the
tropicbird has been found to nest throughout the year (Brandt 1962), as
is probably the case in the Southwest Islands.

Red-footed Booby - Sula sula. The Red-footed Booby is abundant on
the two islands on which it nests, Fanna and Helen, and sightings are
possible near any of the other Southwest Islands. Boobies generally
spend the day foraging over the open ocean, and population estimates
are best made in early morning or at dusk as the birds leave or return
to land. On Helen, it was possible to spend two evenings on the island
and estimate numbers as the birds returned to roost. On Fanna, the
population estimate is derived from a count of active nests. The total
adult population (flying birds) is around 5,000 on Fanna and 2,500 on

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Helen. Nearly all birds (over 90%) are of the white rather than dark
color phase.

The Red-footed Booby is a colonial nester, and constructs nests of
leaves, grass and twigs. On Fanna, the booby nests high in trees along
the perimeter of the island, and to lesser extent in the interior.
Favorite nest trees are Tournefortia and Artocarpus. Residents of
Sonsorol state that the booby roosts so profusely at times that nest
trees are injured, and indeed, several trees were conspicuously
defoliated in May 1979. There were at least ten distinct sites in May
1979, each with nearly 100 active nests. Thus, there were about 1,000
active nests on the island. Young were at all stages of development.
On Fanna, peak nesting activity occurs during spring months, and there
is little or no nesting in the fall. A nesting cycle was apparently
beginning in November 1977, when adult birds were on the ground picking
up twigs and sitting on nests up in trees. However, I could see no
young or eggs from below.

On Helen, the colony is smaller, but density is greater. Birds
nest in the relatively low Tournefortia trees, and on rare occasions in
the much taller coconut trees (both Tournefortia and coconut trees are
utilized for roosting). About 265 downy young, along with a few nearly
fledged birds, were counted in May 1979. In October 1979, 91 young at
all stages of development were counted (King et al. 1980), and in
November 1977, 25 young were found (this study). The pattern indicates
nesting throughout the year, with a probable peak in spring months.

Brown Booby - Sula leucogaster. The Brown Booby is known to nest
only on Helen and, in very limited numbers, on Fanna. On Helen, the
colony numbers from 500 to 1,000, but on Fanna, fewer than 25 are
present. The species can probably be sighted near or possibly roosting
on any of the other Southwest Islands.

On Helen, pairs nest in shallow lined scrapes in the sand, often
just above the high tide line. Concentrations of nesting birds are
located under Tournefortia trees on the northern and southern portions
of the island. A few young are raised throughout the year, but the
peak nesting season is in spring months. In November 1977, I counted
10 downy young and saw no incubating adults. Likewise, there was only
minor nesting activity in November 1978, when only one nest was found
(Bright 1978) and in October 1979, when 11 active nests were located
(King et al. 1980). In May 1979, the peak of the presumed nesting
season, I counted 60 downy young of all sizes, along with at least 20
incubating adults. Large numbers of birds returned at dusk to roost on
the Island.

Residents of Sonsorol informed me of a small colony of fewer than
25 birds that recently began nesting on Fanna. Although I visited
Fanna in both fall and spring and observed Brown Boobies in the area, I
discovered no nests. This new colony may succeed provided it is not
unduly disturbed by humans, and provided the relatively exposed beaches

prove suitable as nesting sites. It is possible that only Helen, whose
beaches are protected by an outer reef, is capable of sustaining a
stable colony of nesting Brown Boobies.

Great Frigatebird - Fregata minor, and Lesser Frigatebird -
Fregata ariel. Frigatebirds occur uncommonly but widely on the oceans
around Palau, and can characteristically be seen soaring above any of
the Southwest Islands. Great Frigatebirds roost on all of the
Southwest Islands. Lesser Frigatebirds have been recorded from Merir
and Helen, but no doubt frequent the other Southwest Islands as well.
Discussion of these two species is combined partly because of the
incomplete information regarding relative numbers of each species. Out
of 400 frigatebirds at Fanna in May 1979, I identified nearly 150
individuals, all of which were Great Frigatebirds. Only a few
individuals, all Great, were identified at Pulo Anna, Merir, and Tobi.
Thus, the great majority of frigatebirds on these- islands appears to be
Great Frigatebirds. At Helen, I found approximately equal numbers of
the two species in May 1979, as did King et al. (1980) im October 1979.
In May 1969, however, Owen (1977a) found 25 to 30 Great and over 100
Lesser Frigatebirds on Helen.

Although Great Frigatebirds roost on all the Southwest Islands,
only Fanna is reported to have a nesting colony. Residents informed me
that the birds nest high in the trees in the spring of the year. In
May 1979 when about 400 frigatebirds were present, I observed birds
entering tall trees during the day, but I could locate no nests.
Occasional sporadic nesting may occur on other Southwest Islands as
well. Residents have reported nesting on Merir, and in May 1969, Owen
(1977a) recorded one male Lesser Frigatebird on a nest at Helen Island.

The following number of frigatebirds was recorded during several
trips to the region:

May Nov. Nov. May Oct.
1969 1977 1978 1979 1979
(Owen (this (Bright (this (King et
1977) report) 1978) report) al. 1980)
Fanna over 400
100
Pulo
Anna 60 15
Merir 34 over 10 moderate
150 numbers
Tobi 26 1
Helen over 300 25) moderate

130 numbers

The largest concentrations are found throughout the year on Fanna and
Helen. The number of birds on each island varies, suggesting that
birds travel from one island to another. The data also indicate that
birds concentrate to nest at Fanna during the spring months.
Frigatebirds are highly mobile, and much of the population may
originate from or move to areas outside Palau. For example, Lesser
Frigatebirds that nest on the Line Islands have been recorded in the
vicinity of the Southwest Islands and beyond, a distance of over 6,000
km (Sibley and Clapp 1967).

Black-naped Tern - Sterna sumatrana. This species occurs only on
Helen, where the population is 200-500 birds. It roosts and nests on
shipwrecks on the surrounding reef. In May 1979, the species was con-
spicuous, and small groups could be seen foraging above the lagoon or
circling near shipwrecks. Only a few were seen near the island itself,
either resting on sand spits at low tide or circling overhead. On this
same trip I visited an abandoned ship east of the island, where about
50 terns perched on and circled the ship. One chick and about 20 eggs
were found on the deck. Sabino Zacharias, a resident of the island,
informed me that greater numbers of birds resided at the other three
shipwrecks on the reef. The nesting season appears to be in spring
months only. Despite the relative abundance of Black-naped Terns in
May 1979 and the apparently well established nesting population, there
are no records of sightings during the fall. The disappearance of the
population outside the breeding season is puzzling, since they are
relatively sedentary elsewhere in the Palau Archipelago.

Sooty Tern - Sterna fuscata. Helen harbors the only colony of
Sooty Terns in the Southwest Islands. This highly pelagic species
returns to land only to nest, and, depending on the reproductive cycle,
numbers fluctuate from a few hundred to tens of thousands on Helen.
Despite the occasional abundance of birds at Helen, sightings of Sooty
Terns near the other Southwest Islands are rare. During my two trips
through the region, I heard and saw Sooty Terns only at Helen.

At Helen, eggs are located in shallow scrapes on the ground,
usually within the interior of the island well above the high tide
line. The major nesting colony is located in the central and eastern
portion of the island, which is a relatively open area interspersed
with small grass clumps. MThis colony extends to well within the
interior of the island during a peak nesting season. Another small
colony, possibly a distinct population, is located on the beach on the
southwest side of the island. Birds appear to avoid nesting under the
trees. The nesting of Sooty Terns on Helen appears to follow no
distinct annual cycle. On several trips, the following estimated
numbers of nests and young were recorded:

Nov.
1977
(this
report)

five nests
and 15
nearly
grown young

150 to 200
adults

(east side)

From this limited data,

Nov.
1978
(Bright
1978)

500 nests

no estimate
of adults

(southwest
side)

May
1979
(this
report)

10 nearly
grown
young

50 adults

(southwest
side)

Oct.
1979
(King et
al. 1980)

37,876 eggs
and small
chicks and
3,000 nearly
grown young

82,000 adults

(east side)

it appears that the only concentration of
nesting birds during this 2-year period was in the fall of 1979.

This

is in contrast to the normal spring breeding peak for most seabirds of

the region.

different nesting seasons,

1962))<

Crested Tern - Thalassius bergii.

Elsewhere in Micronesia, the species seems to have several
but these are poorly described (Brandt

The Crested Tern nests only at

Helen, where it can regularly be observed in large numbers resting on

sand spits or foraging within or near the lagoon.
season, the adult population is estimated at around 7,000.

During the nesting
Uncommon

visits are made to other Southwest Islands as well, and I recorded
small groups near Pulo Anna, Merir, and Tobi.

The Crested Tern exhibits a distinct nesting season, with peak
activity in spring and little or no nesting activity during the

remainder of the year.

Nov.
1977
(this
report)

12 chicks

No eggs

2-3,000
adults

Nov.
1978
(Bright
1978)

No chicks

No eggs

Adults not
estimated

May
1979
(this
report)

No chicks

3,250 eggs
incubated

7,000 adults

The following numbers illustrate the pattern:

Oct:
1979

(King et
al. 1980)
10 small chicks

20 eggs being
incubated

440 adults

I7/

In May 1979, the birds were at or near the height of their breeding
cycle. The colony was located on the northern tip of the island on a
level, open, sandy area just above the high tide line. Single eggs
were deposited directly on the sand with no nest,being made. By
pacing, I estimated the,size of the colony at 425 m , there being about
240 eggs in every 25 m or about 4,080 total eggs. It appeared that
nearly a fifth of these eggs were abandoned, and I thus estimated a
total of 3,250 active nests. According to King et al. (1980) this is
probably the largest nesting colony of Crested Terns in Micronesia. A
small amount of nesting occurs outside the spring breeding season. In
October 1979 King et al. (1980) noted a small colony (about 20 eggs) on
the eastern side of the island between the Sooty Tern colony and the
beach.

Although the Crested Tern is fairly sedentary in Palau and large
numbers can generally be found roosting and feeding at Helen throughout
the year, they apparently wander from Helen Island outside of the
nesting season. King et al. (1980) observed only 440 roosting adults
in October 1979, a marked decrease from the 7,000 or more that were
present in spring of the same year. During their absence from Helen,
the birds possibly disperse to the northern coast of New Guinea.

Brown Noddy - Anous stolidus. The Brown Noddy is widespread, and
can be found on all the Southwest Islands except Helen. On Sonsorol,
Pulo Anna, and Tobi, Brown Noddies reside at approximately the same
densities. On each of these islands, I estimate the nesting population
to number in the high hundreds or low thousands. At Merir, the
population is slightly larger, and on Fanna, it is smaller, at least
during spring months. The small size of the population on Fanna may be
due in part to interspecies competition for nesting sites with Black
Noddies, which nest in profusion on Fanna in spring. The Brown Noddy
breeds moderately throughout the year, with a decided peak during
spring months. Nests are placed in trees, frequently in the crown of a
coconut or pandanus. The bird is relatively solitary in its nesting
habits, and generally only one nest is placed in a tree.

Certain populations of Brown Noddies apparently indulge in
seasonal migrations in the Southwest Islands, though in the main Palau
Archipelago, numbers are similar throughout the year. In November
1977, I recorded no Brown Noddies from Pulo Anna or Tobi, yet in May
1979, the species was nesting in abundance on both islands. On Merir
and Sonsorol, however, birds were present in both fall and spring.
Possibly the Pulo Anna and Tobi birds migrate to Sonsorol or Merir
during the fall, but they may also journey to regions outside of the
Southwest Islands. It was suggested by a resident of Tobi that the
complete absence of noddies in November 1977 was the result of
overharvesting the birds with a gun, rather than a natural phenomenon.

Black Noddy —- Anous minutus. A colonial and abundant nester on
Fanna and Helen, the species occurs in much lesser numbers on the other
Southwest Islands. Peak nesting occurs in spring on Fanna, but on

Helen nesting activity continues throughout the year. At Fanna in
November 1977, the species was abundant, but I found no nests. In May
1979, the colony was nesting profusely around the perimeter of the
island up to 100 m inland. Nests, placed in branch crotches, were
constructed of twigs, leaves, and other debris, and were heavily caked
with excrement. They were placed at all levels in medium-sized trees.
Counts at ten random points within the colony revealed an average of 64
active nests within a 20 m radius of each point. I estimated the total
area of the colony at nearly 20 ha, and the total number of active
nests at 10,000. At any time during the day a dense cloud of several
hundred to several thousand birds could be seen foraging within sight
of the island.

In contrast to Fanna, the colony on Helen did not exhibit such
marked seasonality in nesting. On all trips that I or other visitors
have made to the island, a large number of birds was nesting regardless
of the season. On Helen, the Black Noddy nests nearly exclusively in
the low Tournefortia trees. In November 1977, I estimated 1,700 active
nests at all stages of development, from eggs to fully fledged young.
In May 1979, I recorded about 1,000 nests. King et al. (1980) in
October 1979, recorded roughly 1,200 nests.

Outside of Fanna and Helen, there are no large colonies of Black
Noddies in the Southwest Islands. In November 1979, I saw none at Pulo
Anna, Merir, or Tobi. In May 1979, a very few were present at
Sonsorol, Pulo Anna, and Tobi, but in all cases they were vastly
outnumbered by Brown Noddies. King et al. (1980) observed moderate
numbers on Merir in October 1979, but they were outnumbered by Brown
Noddies 20 or 30 to one. Presumably a few birds nest on other
Southwest Islands, although it remains to be documented. From the
limited information I have from the Southwest Islands, I detected no
major movement patterns.

Wherever Black Noddies are abundant there were no or few Brown
Noddies, and superficially it appears that some form of interspecific
competition exists. However, I feel that more is involved than mutual
exclusion due to competition for food, nest sites, or other habitat
parameters. A possible partial explanation is the influence of man on
the two species of noddies. The Black Noddy may be susceptible to
disruption by humans, as they are abundant on the traditionally
uninhabited islands of Fanna and Helen. The Brown Noddy, however, may
be more tolerant of human disruption, and has persisted on islands
inhabited by man.

White Tern - Gygis alba. The White Tern is common to abundant on
all the Southwest Islands except Helen, where a recently established
colony of under 50 birds resides. The largest concentration is on
Fanna, where several thousand birds nest. Lesser numbers, in the
hundreds or low thousands, are found in the forests of Sonsorol, Pulo
Anna, Merir, and Tobi.

Unlike most other seabirds, the White Tern is not strongly averse
to humans, and frequently resides within or near villages. Individuals
or pairs forage far out over the ocean, and are usually not seen
feeding near land. Birds do not return nightly to roost, as
individuals and small groups can occasionally be seen or heard flying
over water after dark. Birds roost and nest in trees, usually high in
large spreading trees such as Ficus, Calophyllum, or Artocarpus. When
over land, birds are raucous and conspicuous, especially during morning
hours.

The White Tern nests throughout the year in Micronesia (Baker
1951), and presumably does so within the Southwest Islands as well.
Though the tern is not a highly colonial nester, several pairs usually
occupy the larger, more desirable trees. A peak in nesting activity
may occur in spring. On Fanna, Pulo Anna, and Tobi in May 1979,
numerous birds repeatedly landed and lingered in the foliage of the
upper canopy, and were noisy and active as if defending territories.
Birds were evenly distributed throughout the forest except on Fanna,
where the colony of White Terns did not overlap with the dense and
extensive colony of Black Noddies. Though I could not locate eggs or
young, a few individuals perched on branches and appeared to be
incubating. A nesting cycle had apparently begun or was just
beginning. In November 1977, White Terns on these islands were
decidedly less active. Though a peak in nesting may occur in spring,
nesting activity has been recorded in other months as well. In
November 1977 on Sonsorol, I noted White Terns carrying small fish,
possibly for feeding young. In October 1979, an incubating bird was
observed on Helen (King et al. 1980).

The small colony of White Terns on Helen became established in
1978. In November 1977, no White Terns nested or roosted on Helen. A
year later, Bright (1978) found at least 20 terns on the island, and
nesting was reported by residents. The colony has remained on the
island at least through the fall of 1979, as I found birds in May 1979,
and King et al. (1980) found a few in October of the same year.

CONCLUS ION

Though perhaps depauperate from a worldwide perspective, species
diversity of seabirds in the Southwest Islands is comparable to other
Micronesian island groups: there are eleven resident seabirds in the
Southwest Islands, about nine in Yap, ten in the Marianas, nine in
Truk, ten in Ponape, sixteen in the Marshalls, and ten in the Gilberts
(Fisher 1950, Baker 1951, Brandt 1962, Amerson 1969, pers. observ.).
The Marshall Islands group has a species diversity noticeably greater
than the other island groups. ,The Marshalls, however, cover a
relatively vast area on the northeastern edge of Micronesia, where
components of the Hawaiian avifaunal community are represented. The
seabirds of the Southwest Islands are almost exclusively tree-nesters,
suggesting that humans or other predators have excluded certain

ground-nesting species. Micronesia, on the other hand, might simply
not provide the nesting habitat or food required for many seabirds.

The Southwest Islands are heavily vegetated, a condition that certain
ground nesting species avoid, and waters may be infertile, a likely

case for offshore tropical waters where there are no major upwellings
(King 1967).

Seabirds of the Southwest Islands presently survive under
relatively undisturbed conditions, though in the past there might have
been considerable human pressure on the resource. Introduced predators
appear to be a minor problem, as I saw no rats, cats, or dogs while on
the islands. Rats are almost certainly present, as they are on most
Pacific islands, but they are apparently not abundant. Pigs were
raised on Sonsorol and Tobi, but those that I saw were penned or
tethered. The only actual predation I witnessed was on Fanna, where a
land crab was eating a Black Noddy downy young. A locally catastrophic
event occurred on Helen in May 1979, when a gravid green sea turtle
(Chelonia mydas) wandered through the Crested Tern colony, destroying a
swath of eggs nearly a meter wide.

Seabirds are well adapted to such natural disturbances, but most
of man's activities are more destructive. It is perhaps no coincidence
that the two largest concentrations of seabirds occur on Fanna and
Helen, islands that have both been historically uninhabited or
otherwise protected from excessive human intrusion. It is probable that
only a few birds could exist on islands that sustained high human
populations. On Tobi in the 1800's, 3-400 Micronesians resided in a
continual state of near famine (Holden 1836) and any bird that lingered
on the island was no doubt quickly consumed. From 1832-1834, Holden
(1836) was a castaway on Tobi, and states that "during our stay there,
scarcely a solitary sea-fowl was known to have alighted on the island."
Many of the Southwest Islanders now reside in the capital of Koror, and
the pressure of large human populations has somewhat diminished.
Threats from outside harvesting still remain. Korean fishermen
recently devastated seabird colonies in the Southwest Islands (Johannes
1981). In May 1979, two Taiwanese vessels were apprehended for illegal
harvesting of birds, fish, and turtles. A Taiwanese vessel was in
Helen Lagoon when the Lindblad Explorer visited Helen in 1979 (W. King,
pers. comm.). Pillaging by outside boats is a common occurrence.

With greater public awareness and more education, Palauans are
expressing increasing concern for their unique natural resources. On
past trips to the Southwest Islands, eggs and birds have been
occasionally taken by field trip members. These incursions are more
the result of unbounded curiosity than any real subsistence needs; an
educational lecture would do much to minimize disturbances. Disruption
of colonies is particularly damaging during nesting, when incubating
adults are easily frightened off their nests and eggs and young are
lost. Because of their high densities, birds on Helen are especially
susceptible to such losses. On Helen, a warden has been designated to
assist in the protection of seabird colonies; positive actions such as
these will assure the continued existence of Palau's seabird colonies.

Acknowledgments

I would like to first thank Robert P. Owen, who initiated this
project and supported it throughout its duration. Warren King's timely
contribution of his, Dennis Puleston's, and Thomas Ritchie's
observations is much appreciated. Greg Bright helpfully offered his
observations of the islands. Storrs Olson and John Farrand, Jr.,
kindly aided in the handling of specimens. Helpful comments on the
manuscript were contributed by Dr. Cameron Kepler, Kay Kepler,
Roger Clapp, and Warren King. Dr. Derral Herbst contributed much of
the botanical information. Funding for the field work was supplied in
part by the National Audubon Society through the efforts of
C. John Ralph and George Peyton, Jr. A number of Palauans cheerfully
offered information and assistance, and I would especially like to
thank Sabino Zacharias, Marianos Carlos, and Antonio Andres.

References

American Ornithologists' Union. 1982. Thirty-fourth supplement to the
American Ornithologists' Union check-list of North American birds.
Auk (Supplement) 99(3): 16p.

Amerson, A. J. Jr. 1969. Ornithology of the Marshall and Gilbert
Islands. Atoll Res. Bull. No. 127: 348p.

Baker, R. H. 1951. The avifauna of Micronesia, its origin, evolution,
and distribution. Univ. Kan. Pub. Mus. Nat. His. 3(1): 359p.

Brandt, J. H. 1962. Nests and eggs of the birds of the Truk Islands.
Condor 64(5):416-437.

Bright, G. 1978. Ornithological notes from the Southwest Islands, 24
November to 2 December 1978. Unpubl. report, Office of the Chief
Conservationist, Koror, Palau. 2p.

Bryan, E. H., Jr. 1971. Guide to place names in the Trust Territory
of the Pacific Islands. Pac. Sc. Inf. Center, Bernice P. Bishop
Museum, Honolulu. (pages not numbered)

Sibley, F. C., and R. B. Clapp. 1967. Distribution and dispersal of
Central Pacific Lesser Frigatebirds Fregata ariel. Ibis
109: 328-337.

Eilers, A. 1935. Westkarolinen, 1. Halbband: Songosor, Pur, Merir.

In G. Thilenius (ed.), Ergebnisse der Stidsee—-Expedition 1908-1910.
II, B, IX, part 1. Friederichsen, De Gruyter, Hamburg.

- 1936. Westkarolinen, 2. Halbband: Tobi, Ngulu. In
G. Thilenius (ed.), Ergebnisse der Sudsee-Expedition 1908-1910.
II, B, IX, part 2. Friederichsen, De Gruyter, Hamburg.

Engbring, J. 1981. A field guide to the birds of Palau. Unpubl.
report, Office of the Chief Conservationist, Koror, Palau. 113p.

Engbring, J. and R. P. Owen. 1981. New records of birds in
Micronesia. Micronesica 17(1&2):186-192.

Fisher, H. I. 1950. The birds of Yap, Western Caroline Islands.
Pacific Science IV(1):55-62.

Holden, H. 1836. A narrative of the shipwreck, captivity, and
suffering of Horace Holden and Benjamin Nute. Weeks, Jordan and
Co., Boston.

Hutchinson, G. E. 1950. Survey of existing knowledge of
biogeochemistry, 3. The biogeochemistry of vertebrate excretion.
Bull. Amer. Mus. Nat. Hist. 96: 232-233.

Johannes, R. E. 1981. Words of the lagoon; fishing and marine lore in
the Palau District of Micronesia. Univ. of California Press,
Berkeley. 245p.

King, B. F., E. C. Dickinson, and M. W. Woodcock. 1975. A field
guide to the birds of South-East Asia. Collins, London. 480p.

King, W. B. 1967. Preliminary Smithsonian identification manual;
seabirds of the tropical Pacific Ocean. U.S. Nat. Mus.,
Smithsonian Institution, Washington, D.C. 126p.

King, W. B., D. Puleston, and T. L. Ritchie. Ms dated 1980. Bird
populations of Helen and Merir Islands, Southwestern Palau.
Unpublished. /7p.

Owen, R. P. 1977a. New bird records for Micronesia and major island
groups in Micronesia. Micronesica 13(1):57-63.

1977b. Terrestrial vertebrate fauna of the Palau Islands.
Unpubl. report, Office of the Chief Conservationist, Koror, Palau.
15p.

MO Fier. A checklist of the birds of Micronesia.
Micronesica 13(1):65-81.

Yamashina, Y. 1940. Some additions to the list of the birds of
Micronesia. Tori 10:673-679.

ATOLL RESEARCH BULLETIN
No- 268

RECENT HISTORY OF A FRINGING REEF, BAHIA SALINA DEL SUR,
VIEQUES ISLAND, PUERTO RICO

IAN G- MACINTYRE, BILL RAYMOND AND ROBERT STUCKENRATH

ISSUED BY
THE SMITHSONIAN INSTITUTION
WASHINGTON, D- C-, U-S-A.-

SEPTEMBER 1983

RECENT HISTORY OF A FRINGING REEF, BAHIA SALINA DEL SUR,

VIEQUES ISLAND, PUERTO RICO
by

Ian G. Macintyre,1 Bill Raymond, 2 and Robert Stuckenrath?

Introduction

The effect of U. S. Navy training activities on the shallow-water
reefs at the eastern end of Vieques Island, Puerto Rico, was
investigated during a 1978 ecological survey that included the drilling
of three short core holes into an Acropora palmata (Lamarck) reef off
the east coast of Bahia Salina del Sur (Figure 1). Radiocarbon dates
of five core samples yield new information on the accumulation rates of
A. palmata reef sections and provide further evidence that framework
communities of many sea-level reefs are migrating leeward over loose,
back-reef sediments.

General Setting

Bahia Salina del Sur is a small, crescent-shaped embayment
(approximately 1 km wide and 1 km long) on the south coast of Vieques
Island and close to its eastern end (Figure 1). The Thalassia sea-
grass and sand and rubble floor in this area do not exceed a depth of
7m (Raymond, 1978). Shallow reefs fringe the promontories on the
eastern, western, and northern shores of the bay, and two extensive
sand beaches border its northeastern and northwestern corners.

The fringing reef off the west side of the bay consists of a well-
developed Acropora palmata community. Small coral heads grow beneath
the open framework of A. palmata, which extends to a depth of 5m, where
a halo of sand separates the reef from adjacent broad beds of
Thalassia. This halo of sand may be related to the feeding activity of
fish and sea urchins (Ogden and Zieman 1977).

Banks and mounds of Porites porites (Pallas)--which resemble the
near-shore banks of Porites off the west coast of Barbados (Macintyre
1968) and off the southeast coast of St. Croix (Adey 1975)-- have
developed around two distinct promontories on the north coast of Bahia
Salina del Sur. Small scattered stands of Acropora palmata occur in )
association with these Porites buildups. During the May, 1978 survey
it was observed that naval bombardment had destroyed the eastern end of
this near-shore community. During a subsequent survey following
Hurricane David, Raymond and Dodge (1980) found that storm waves had
Tyational Museum of Natural History, Smithsonian Institution,

Washington, D.C. 20560.

~Ocean Research and Survey, Inc., Fort Lauderdale, Florida 33136.

3Radiation Biology Laboratory, Smithsonian Institution, Washington,
D.C. 20560.

Manuscript received Jan. 1982--Eds.

almost completely destroyed the entire north-shore Porites community,
along with most of the A. palmata on the south coast of Vieques.

The reef cored during this study (designated S-5 reef in Antonius
and Weiner's 1978 survey) juts out obliquely from about the center of
the eastern shore of Bahia Salina del Sur and is protected in part by
a large promontory that forms the eastern entrance to the hay and by
the fringing reef adjacent to this promontory, which consists of
Montastrea, Siderastrea, and Diploria coral heads. Additional protec-
tion is afforded by the A. palmata reef surrounding Roca Alcatraz, an
island 1 km south of S-5 reef (figure 1). S-5 reef has the characteris-
tic zonation of shallow-water Caribbean reefs dominated by Acropora
palmata in the reef crest and shallow fore reef (Figures 2, 3D,E,F)
(see, for example, Dahl et al. 1974; Adey 1975). At a depth of 4m,
the A. palmata community gives way to a mixed coral-head community that
includes Montastrea annularis (Ellis and Solander), Diploria strigosa
(Dana), and Siderastrea siderea (Ellis and Solander). Small scattered
colonies of both Acropora cervicornis (Lamarck) and Acropora prolifera
(Lamarck) were found in the shallow fore reef during the 1978 survey,
but subsequently were almost entirely removed by storm surge associated
with Hurricane David (Raymond and Dodge 1980). The seaward slope of
S-5 reef levels off at a depth of 8 m, where it grades into the
sediment floor of the bay (Figure 2). The back reef shoreward of the
reef crest is composed of large colonies of Montastrea annularis on
rubble and pavement, which grade into sand and rubble; only a few
colonies of M. annularis occur at the inner limit of the drill-site
transect (Figures 2, 3A,B,C).

Its faunal zonation indicates that S-5 reef has developed under
moderate wave-energy conditions (Geister 1977). The algal ridges or
Palythoa-Millepora reef-crest communities characteristic of high wave-
energy reefs are absent here, as are Acropora cervicornis or Porites
porites communities in low wave-energy reefs. Wave agitation does
appear to be strong enough to prevent any significant accumulation of
the fragile Acropora cervicornis either in the deeper fore-reef slope
or in the protected back-reef sand flats.

Core Descriptions

Three core holes were drilled at 50-m intervals along a transect
crossing S-5 reef and adjacent to the eastern coast of Bahia Salina
del Sur (Figure 1)--two into the reef crest in a water depth of about
0.5 m and one into the shallow fore-reef slope in a water depth of 2 m
below mean sea level (Figure 2).

Core hole 1, drilled in four intervals into the reef crest to a
depth of 6.4 m, yielded the following material:

1. O-.61 m.--This interval consisted of fresh sections of
Acropora palmata with a comparable amount of fragments
bored and encrusted by Homotrema rubrum, coralline algae,
and serpulids.

2. .61-1.83m.--This section was made up of fresh and bored
sections of Acropora palmata and Diploria strigosa, along
with some encrusted (by Homotrema rubrum and coralline algae)
rubble consisting of A. palmata, D Diploria sp., and Porites

porites.

3. 1.83-3.35--Sections of A. palmata and Diploria clivosa were
found throughout and cave-in rubble at the top of this
interval.

4. 3.35-6.40 m.--Only cave-in rubble was collected from this
interval. On-site observations indicated that the drill
had dropped through a section of sand at this point.

Core hole 2 consists of one core interval drilled to a depth of
1.83 m below the surface of the reef. Except for a 6-cm core of bored
and encrusted Diploria strigosa, the material here was mainly A.
palmata bored to various degrees by sponges, molluscs, and worms and
encrusted by Homotrema rubrum, coralline algae, and serpulids.

Core hole 3, drilled to a depth of 4.88 m below the surface of the
reef, consists of three core intervals:

1. O-1.83 m.--This interval is characterized by extensive
submarine lithification, so that core sections are
predominently agglomerate limestcne. These cores, which
are identical to those described from the shallow fore
reef off Galeta Point, Panama (Macintyre 1977), consist
of extensively bored and cemented agglomerations of
crustose coralline algae, Millepora sp., Porites sp.,
and Acropora palmata. The multicyclic boring and submarine
lithification have in some places destroyed much of the
original skeletal framework, which has been replaced by
Magnesium calcite cement. Other material collected from
this interval consists of bored, infilled, and cemented
A. palmata and other coral debris.

2. 1.83-3.35 m.--Core sections contained mainly Acropora palmata,
both fresh corals and samples bored by sponges, worms, and
molluscs. Extensive cave-in material was present at the
top of this interval.

3. 3.35-4.88 m.--Extensive cave-in rubble occurred in this
interval. Two cores of bored Acropora palmata were also
collected here.

Radiocarbon Dates

Five radiocarbon dates were obtained from fresh samples of
Acropora palmata, which had been collected from the base of core
intervals so as to reduce the error in estimating the depths of
recovery for the dated samples. Even so, it is not known whether the

last material to be cored is in place at the base of the core interval,
since a core barrel can punch through a section of the reef and carry a
sample below its real depth of recovery. The lack of any significant
difference in the two dates from core hole 3, the poor recovery in the
last core interval, and the drill-worn condition of the lower sample
dated suggest that this core sample was carried below its true depth of
recovery. Radiocarbon dates and the accumulation rates for the inter-
vening reef sections are given in Table l.

TABLE 1

RADIOCARBON DATES AND ACCUMULATION RATES,
BAHIA SALINA DEL SUR REEF

Estimated Interval
Depth of of Reef

Core Depth Recovery Section Radio- Accumulation
Interval below Reef Dated carbon Rate
Sample (m) Surface (m) (m) Date (m/1000 yrs)
Hole 1:
Core l 0-.61 6! 0-0.61 190+90 aval
Core 1 0-.61 61 190+90
-61-1.83 0.62
Core 2 -61-1.83 ILS tis) 2155+80
Hole 2
Core 1 0-1.83 183 0-1.83 860+90 Qreilks
Hole 3
Core: 2 IP at}SI3} 5355) 33 55)5) 0-3.35 2020+70 1.66
Core 2 1.88-3.35 3555) 2020+70
3.35-4.88 *
Core 3 3.35-4.88 4.88 2020+70

*Estimates invalidated owing to poor recovery in this core
interval.

Summary and Conclusions

Excluding the lowest section of core hole 3 (where the estimates
were discounted as invalid) we calculated that the Acropora palmata
framework of S-5 reef has an average accumulation rate of about 2m/1000
years, which is lower than the average of 3.9m/1000 years reported for
the A. palmata facies of the fringing reef off Galeta Point, Panama
(Macintyre and Glynn 1976). This difference can be attributed to the
changing rates of sea-level rise in the late stages of the Holocene
transgression. Sea-level curves estahlished for several areas in the
Atlantic and Pacific oceans show a distinct decrease in the rate of
sea-level rise, from 3,000 to 4,000 years B.P. (Macintyre and Glynn
1976). As pointed out in the study of Galeta Reef, accumulation
rates there decreased considerably about this period of time because
changing sea levels reduced the availability of vertical space for
reef development. Wherever A. palmata communities have experienced
rapid changes in sea level, however--for example, at the shelf edge off
Florida 7,000 to 9,500 years ago (Lighty et al. 1978)--the mean
accumulation rates have been estimated at 6.6 m/1000 years, the
maximum rate reported being 10.7 m/1000 years.

The dates from the Vieques cores suggest that shallow-water
Acropora palmata framework that is less than 2,000 years old can be
expected to have accumulation rates around 2m/1000 years. In addition,
the penetration of more than 3 m of sand at the base of core hole 1
lends support to Shinn's (1980) observation that some shallow-water
A. palmata framework may accrete leeward over back-reef sands "by
corals establishing themselves on storm-derived rubble periodically
transported onto the leeward side of the reef flat" (p. 651).
Observations of S-5 reef before and after Hurricane David indicate
that both dead and living A. palmata, along with coral head debris,
migrated several meters over the back-reef sands in this area.
Furthermore, the extensive and multicyclic cementation present at the
top of the shallow fore-reef core hole 3 is a characteristic
associated with slowly accumulating reef facies (Macintyre, 1977).

This combination of relatively little present-day reef growth in
the shallow fore reef and leeward migration of the reef flat indicates
that S-5 reef is in a mature stage of reef development, extending
laterally into the Bahia Salina del Sur.

Acknowledgments

Thanks go to Robin King, Mike Wolfe and Greg McIntosh, as well
as the Navy E.0O.D. divers of Roosevelt Roads, P.R. for assisting with
the field work. Also, thanks to the Navy helicopter pilots who air-
lifted the coring equipment from San Juan to Vieques.

W. T. Boykin's assistance with drafting is gratefully
acknowledged.

References

Adey, W. H. 1975. The algal ridges and coral reefs of St. Croix: Their
Structure and Holocene development. Atoll Res. Bull.,
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Antonius, A. and A. Weiner. 1978. A quantitative biological and health
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and the U. S. Virgin Islands. Report submitted to EG&G/U.S.
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Dahl, A. L., I. G. Macintyre, and A. Antonius. 1974. A comparative
survey of coral-reef research sites. Atoll Res. Bull.
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Geister, J. 1977. The influence of wave exposure on the ecological
zonation of Caribbean Coral Reefs. Pages 23-99, in D. L.
Taylor, Editor, Proceedings, Third International Coral Reef
Symposium, Volume 1, Miami, Florida: Rosentiel School of
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Lighty, R. G., I. G. Macintyre, and R. Stuckenrath. 1978. Submerged
early Holocene barrier reef south-east Florida shelf. Nature
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Macintyre, I. G. 1968. Preliminary mapping of the insular shelf off
the West coast of Barbados, W.I. Caribbean Jour. Sci.,
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Macintyre, I. G. and P. W. Glynn. 1976. Evolution of modern Caribbean
fringing reef, Galeta Point, Panama. Am. Assoc. Petroleum
Geologists Bull. 60:1054-1072.

Macintyre, I. G. 1977. Distribution of submarine cements in modern
Caribbean fringing reef, Galeta Point, Panama. Jour. of Sed.
Petrology, 47:503-516.

Ogden, J. C. and J. C. Zieman. 1977. Ecological aspects of coral
reef-seagrass bed contacts in the Caribbean. Pages 377-382.
In D. L. Taylor, editor. Proceedings, Third International
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School of Marine and Atmospheric Science.

Raymond, Bill, 1978, The marine sediments of a Naval Bombing range,
Vieques, Puerto Rico: Report submitted to EG&G, U.S. Navy,
Us iS Depts o£ Gusticey) Deck Wo7sr

Raymond, W. F. and R. E. Dodge. 1980. 1979 Hurricane damage to coral
reefs of Vieques. Report submitted to U.S. Navy.

Shinn, E. A. 1980. Geologic history of Grecian rocks, Key Largo
Coral Reef Marine Sanctuary. Bull. Mar. Sci. 30:646-656.

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Figure 3. Bottom photographs of S-5 reef taken along transect
shown in Figure 2. A. Isolated colonies of Montastrea annularis
on sand and rubble bottom, at 5 m along transect. B. and C. Back-
reef M. annularis colonies at 30 and 50 m, respectively. D, E,
and F. A. palmata community on the reef crest in the vicinity of

core hole 1 and 2, and on the shallow fore-reef, near core hole 3.

ATOLL RESEARCH BULLETIN
No- 269

THE INVERTEBRATES OF GALETA REEF (CARIBBEAN PANAMA) :
A SPECIES LIST AND BIBLIOGRAPHY

JOHN CUBIT AND SUELYNN WILLIAMS

ISSUED BY
THE SMITHSONIAN INSTITUTION
WASHINGTON, D- C-, U-S-A-

SEPTEMBER 1983

CONTENTS

Abstract
Introduction
Explanation of Listings
Porifera
Coelenterata
Platyhelminthes
Sipuncula

Annelida

Arthropoda

Mollusca

Ectoprocta (Bryozoa)
Brachiopoda
Echinodermata
Chordata
Acknowledgments

Literature Cited

page

THE INVERTEBRATES OF GALETA REEF (CARIBBEAN PANAMA)
A SPECIES LIST AND BIBLIOGRAPHY

by John cubits and Suelynn WMulidems”

ABSTRACT

The fringing coral reef at Galeta Point, on the Caribbean Coast of
Panama, has been under intensive study for approximately ten years. The
combined studies of the reef represent approximately 5,000 person hours
of field sampling and have documented the presence of approximately 775
species of invertebrates. A list of these species is presented here
together with annotations to all known sources of information pertaining
to the occurrence of these species on Galeta Reef. For most species
these records are the southernmost in the Caribbean Sea.

INTRODUCTION

The following is an inventory of the invertebrates that have been
found on Galeta Reef, Panama, together with all known sources of
information pertaining to the occurrence of these species on the reef.
At present such data are lacking for Caribbean reefs, but are needed to
formulate rational policies of resource management and to serve as
baseline information for measuring natural and man-caused changes of the
environment (FAO, 1969). This need was recently reiterated by the
United Nations Environment Program (UNEP,1981). We have compiled this
list from published papers, unpublished reports, personal
communications, our own observations, and the set of specimens in the
reference collection of the Galeta Point Marine Laboratory. This
listing has been restricted only to those invertebrates studied on, or

1. Smithsonian Tropical Research Institute, Box 2072, Balboa, Panama.

2. Present address: 9 Second Street, Route 4, West Riverside, Missoula,
Montana 5980

Manuscript received May 1982 -- Eds.

collected from, Galeta Reef itself; it does not include species reported
from nearby areas or the general Caribbean coast of Panama.

Galeta Reef has been under intensive investigation for approximate-
ly ten years. Most of the reef studies have been monitoring surveys
designed to determine the species composition of the reef and to
document temporal changes in the distribution and abundance of the biota
of the reef.

This reef was established as a biological reserve in the late
1960s. Intensive monitoring of the reef biota was started by Charles
Birkeland and others in 1970, beginning with a three-year program

Figure 1. Map of Caribbean Sea showing the location of Galeta Point
(9°24'18"N, 79°51'48.5"W) (marked by an arrow at lower left).

Figure 2. Schematic cross section of the reef at
Galeta Point. The reef platform (10 to 300 m
wide) is in shallow water (less than 40 cm deep),
and is occasionally exposed above the level of the
tide (shown as a dashed line). The seaward edge
of the reef has various profiles (shown in the
figure as the solid and dotted lines) which
terminate at 3 to 10 m depth at a base of sand or
coral rubble. The reef platform encloses a lagoon
and channels and is backed on the landward side by
mangroves and sand beaches.

supported by the U.S. Environmental Protection Agency (see Birkeland et
al., 1976). Subsequently the monitoring was expanded to include
physical factors in a set of projects supported by the Smithsonian
Institution Environmental Sciences Program. In addition, the reef has
been studied by a number of visiting investigators. Overall, the
information in this inventory has been derived from the efforts of
approximately 50 people who have conducted a variety of studies, of
variable duration, during the period of 1969 to 1980. Im all, we
estimate that this represents approximately 5,000 person—-hours of
sampling effort of reef invertebrates. The presence of approximately
775 species of macroinvertebrates has been documented in these
investigations of the reef. In these studies certain taxonomic and
ecological groups have received more attention than others. For
instance, the gastropods, polychetes, and certain groups of decapods
have been more thoroughly collected, while the sponges, ascidians,
bryozoans, and smaller crustaceans have not. There is also more
information regarding those invertebrates that are major occupiers of
primary substratum on the shallow reef platform than for those species
that are mobile or occur on the subtidal reef slope and sand bottom.

Description of the Reef

The Galeta Reef is in the southwestern Caribbean Sea (9°24'18"N,
79°51'48.5"W). The Galeta Point Marine Laboratory, situated directly on
the reef platform, is the southernmost marine laboratory in the
Caribbean (see map, Fig. 1). The reef is near the western end of a
system of fringing reefs that stretch for approximately 250 km along the
Caribbean coast of Panama. The majority of these reefs are now at their
post-climax stage, having passed through their period of most active
coral growth more than 2,000 years ago. The general structure of this
type of reef is of a broad platform, bordered on the landward side by
mangroves, and often enclosing a lagoon. On the seaward side, the
platform slopes into 3 to 10 m of water before reaching a sand bottom
(Macintyre and Glynn, 1976; Fig. 2). The surface of the reef platform
is at the lower level of the intertidal zone. The range of the tides on
this coast is only! about 30 cm, so the reef platform is never deeply
under water. Wave action tends to maintain water over the reef even
during the lowest low tides; however, during calm weather the reef
platform may be exposed above water level for long periods of the day,
subjecting the biota of the platform to extremes of desiccation, solar
radiation, high temperatures, rainfall, and predation by shorebirds.
There are approximately 30-40 such instances of reef exposure each year,
varying in duration from 1 to 14 hours.

Other than the extreme low tides, the reef is subject to relatively
little disturbance. Galeta Point is south of the Caribbean "hurricane
belt" (the area traversed by hurricanes and tropical storms) (Neumann et
al., 1978), and is thus protected from this source of periodic
disruption to which most other Caribbean reefs are exposed. Salinity
and seawater temperature have been monitored on this reef for
approximately seven years: there is no evidence that the subtidal biota
are ever exposed to extremes of any of these factors. Mean seawater
temperature is approximately 29°C with the range of variation confined
to plus or minus a few degrees (except during the extreme low tides
previously mentioned, when temperatures in shallow pools of standing
water on the reef platform may reach 35°C to 40°C). Salinities average
approximately 33 ppt, also with little variation (except for those
organisms above water level which may be exposed to heavy rains).

Most of the hard substrata of the reef platform are covered with
algae, primarily the two red algae Acanthophora spicifera (Vahl)
Borgesen and Laurencia papillosa (Forsskal) Greville. The seagrass
Thalassia testudinum Koenig and Sims occupies much of the area of loose
sediment. The biota of the subtidal reef slope consists of various
species of foliose and crustose coralline algae, some fleshy algae, and
live corals. Most of the species in this inventory were collected from
the reef platform.

Explanation of Listings

All entries on this list are followed by notations which refer to
the following: (1) published information regarding the occurrence of
the species on Galeta Reef, (2) to whom to attribute the determination
of the species, and (3) the presence of voucher specimens in the Galeta
laboratory reference collection. Because of the large number of
entries, we have had to abbreviate these notations. The meanings of the
abbreviations are listed at the end of the inventory and follow this
form:

1. Multiple capital letters are the initials of those persons who
have made the species determinations of the specimens collected
from Galeta Reef.

2. The single capitals B, D, F, and G refer to appendices in
Birkeland et al. (1976), the single most comprehensive survey of
Galeta Reef.

3. E/73-E76 refer to reports of the Environmental Sciences Program
for the years numbered.

4. Lower case letters denote references listed under Literature
Cited.

5. + signifies voucher specimens of the species are present in the
reference collection at the Galeta Point Marine Laboratory.

To aid users of this list and to avoid compounding errors, we have
noted any variations in nomenclature and spelling among the sources. We
refer the user to the sources in the annotations for the authors of the
species.

Abbreviations Used

SPECIES DETERMINATIONS

AR Amada A. Reimer
BM 8B. Macurda

CAC C. A. Child

CB Charles Birkeland
cc C. Cutress

DLM David L. Meyer
DLW Diana L. Werder
DS Diane Stoecker

EK Eugene Kaplan
GLH Gordon L. Hendler
HD Hugh Dingle

IT Ina Tumlin

JC John Cubit

JD Judith Dudley

JH Janet Haig

JR Joseph Rosewater
JRY Joyce Redemske Young
JS James Stames

JSG John S. Garth

JW J. Wells

IWE Jd. Wo Porter

KBM Kaniaulono B. Meyer
KS Ken Sebens

KR Klaus Ruetzler

LGA Lawrence G. Abele
PAA Peter A. Abrams

PG Peter W. Glynn

RB R. Bullock

RLC Roy L. Caldwell
RHG Robert H. Gore

RHM R. H. Millar

RM Raymond B. Manning
RO Randy Olson

RS Rick Steger

SS Stephen Shuster

SW Suelynn Williams
VB Victoria Batista

LITERATURE REFERENCES
B, D, F, G = appendices B, D, F, and G in Birkeland et al., 1976.

E73, E74, E75, E76 = reports of the Environmental Sciences Program of
the Smithsonian Institution (Environmental Monitoring and Baseline Data
from the Isthmus of Panama - 1973, 1974, 1975, 1976, respectively).

= Fauchald (1977)

= Birkeland (1974)

= Bertsch (1975a)

= Reimer (1975)

= Gore and Abele(1976)
= Macintyre and Glynn (1976)
= Sebens (1977)

Meyer (1977)

= Sebens (1976)

= Bertsch (1975b)

= Hendler (1977)

= Abrams (1976)

= Koehl (1977)

= Yee and Chang (1978)
= Lawrence (1976)

= Sebens (1982)

namuyvr onpB rh» Soe hoan op
i]

Sebens and DeRiemer (1977)
Gore (1977)

Porter (1972)

Gore and Abele (1973)
Olson (1979)

Birkeland et al. (1976)
Vasquez—Montoya (1979)
Batista (1980)

Abele (1972)

= Powell (1971)

Smith (1973)

Meyer (1973)

dd = Brattegard (1974)

NMS K EqQerH HR

Ts
a f
wou ot

ee = Lasker (1979)

££ = Lehman and Porter (1973)

gg = Spivey (1976)

hh = Henry and McLaughlin (1975)
ii = Jackson (1973)

43 = Rutzler and Sterrer (1970)
kk = Child (1979)

11 = Southward (1975)

mm = Caldwell (1981)

OTHER

+ signifies this species is currently represented in the reference
collection of the Galeta Point Marine Laboratory.

PORIFERA
Anthosigmella varians E73, E74, E75, E76, v, q
Craniella sp. E73, E74, E/5, E/6
Geodia sp. F
Niphates erecta KR, y
Placospongia sp. E75
Sigmadocia caerulea KR, y
Sigmadocia sp. KR, y
Spongia sp. KR, y
Tedania ignis KR, y

COELENTERATA
(by Order)
HYDROIDA
Millepora alcicornis c
Millepora complanata B, E73, E74, E76; £5) Gi pvemteuein
Millepora moniliformis t
Millepora spp. Vv
Stylaster rosaceus DLM, +
Unidentified sp. y
CERIANTHARIA
Ceriantheopsis americanus y
Cerianthus sp. ey ar
ACTINIARTA
Aiptasia tagetes By ly oq oe
Anthopleura krebsi Bekesact
Anthopleura sp. 3) O/B) sar
Bartholomea annulata Ls uey:
Bunodeopsis antilliensis 2
Bunodeopsis globulifera KS, ? in y
Condylactis gigantea i bbb
Epiphellia n. sp. B, q, +
Lebrunia coralligens r
Lebrunia danae r
Phyllactis flosculifera q, P. floculifera [sic] in CGB,
E73, E74, E75, E76, +
Phymanthus crucifer GG, Bi, E73, E74, SE7i6),, Goes
Phymanthus sp. E75
Stoichactis helianthus CG, i
Telmatactis americana Breet
Telmatactis roseni B, +

Telmatactis vernonia 16

CORALLIMORPHARTIA

Paradiscosoma neglecta r

Rhodactis sancti-thomae r

Ricordea florida r, v, Recordia in CC, JRY, +
ZOANTHIDEA

Isaurus duchassaingi AR, B, E73, E/6, q, +

Isaurus tuberculatus q

Palythoa caribaeorum B, E73, E/4, E76, g, n, q, v, +

Palythoa gigantea E74

Palythoa sp. E/5, E/6

Palythoa spp. Vv

Palythoa sociatus y

Palythoa variabilis B, E74, d, g, n, q, y, +

Palythoa (= Protopalythoa) grandis q
Parazoanthus parasiticus

Parazonathus swiftii

Zoanthus pulchellus AR, +
Zoanthus sociatus AR, B, F, E73, E74, E75,
E76, g, d, q, y, +
Zoanthus solanderi AR, B, E73, E74, E75, E76, +
Z. solandri [sic] in g, q
Zonathus sp. E76
RHIZOSTOMAE
Cassiopea ?xamachana JC

SCLERACTINIA (by family)
Astrocoeniidae
Stephanocoenia michelinii JW, £, Stephanocoencia [sic] in
io oP
Pocilloporidae
Madracis decatis JW, t, +
Acroporidae

Acropora palmata t, v
Acropora cervicornis t

Agariciidae

Agaricia agaricites JWO, B, E73, E74, E76, £, vs +
Agaricia agaricites forma agaricites t
Agaricia agaricites forma danae E
Agaricia agaricites forma crassa t
Agaricia agaricites forma purpurea t
Agaricia agaricites forma humilis t
Agaricia tenuifolia t
Agaricia spp. Vv
Helioseris cucullata t

Siderastreidae

Siderastrea siderea DIM, Bi £5) Gin ace aaveyGiees
Siderastrea radians By E73, EVGs yt uitee yore

Poritidae
Porites astreoides JW, B, E/3, E74,) B/G), £5) Game enyaies

PR. astroidessin’ Ey sea

Porites branneri SWE eats ct
Porites divaricata t
Porites furcata By E73), E745) Gy) tye camel
Porites porites tay
Porites sp. E76
Faviidae
Colpophyllia amaranthus t

Colpophyllia breviserialis t

Colpophyllia natans JW. ty

Diplora clivosa eg Gla. AY

Diploria strigosa t

Favia fragum DIM, B, E/73,E74,E7/ 6,0 1i,)etsmeyeeeess
Manacina areolata SMS WsaP

Montastrea annularis JW, £5 .t,

Montastrea cavernosa JW, t, +,, Gel) eke

MIL

Rhizangiidae
Astrangia solitaria Beat
Meandrinidae
Dichocoenia cf. stellaris JWP, +
Dichocoenia stokesii Bo iby 4
D. stokesia in E76
Meandrina meandrites t

Meandrina meandrites

var. meandrites JW, +
Mussidae
Isophyllia multiflora t
Isophyllia sinuosa PE, 15 5 ©
Mussa angulosa M25 5 &
Mycetophyllia lamarckana JW, t, +
Mycetophyllia sp. B t
Caryophyllidae
Eusmilia fastigiata t
Dendrophylliidae
Tubastraea aurea t
GORGONACEA
Erythropodium caribaeorum B, E73, E/4, E76, q
Gorgonia flabellum f
Gorgonia spp. Vv

Gorgonia ventalina

PLATYHELMINTHES
Class: Turbellaria

Unident. species y

SIPUNCULA

Aspidosiphon broki

Aspidosiphon speculator
Aspidosiphon spinoscutatus
Aspidosiphon spp. (7 species)
Dendrostomum sp.

Golfingia rimicola

Golfingia spp. (4 species)
Lithacrosiphon spp. (5 species)
Lithacrosiphon sp. 3
Paraspidosiphon fisheri
Paraspidosiphon speciosus
Paraspidosiphon spinoso-scutatus
Paraspidosiphon steenstrupi
Paraspidosiphon spp. (7 species)
Paraspidosiphon sp. 4

Phascolosoma antillarum
Phascolosoma perlucens
Phascolosoma varians
Phascolosoma spp. (7 species)
Phascolosoma spp. 3, 4
Themiste spp. (3 species)

Unident. species

ANNELIDA
(by family)

Ampharetidae
Isolda bipinnata

Isolda pulchella

Melinna n. sp.

Biase
x

xX
Bye
B

Bie kis
2 in) B
Bis) Ba
Bis Lys
B

F
Bais
Baek,
Bie:
B

Amphinomidae
Amphinomid sp. 1 B, FE, +

Amphinomid sp. 2 B, +

Eurythoe complanata Bo Wo By Gly &

Hermodice carunculata B, a, q, y

Linopherus canariensis a (family Phyllodocidae in B)

Unident. species y

Aphroditidae

Aphrodita diplops
Aphrodita n. sp. B

Arabellidae

Arabella mutans B, F, a, x, y, +

Arabella sp. indet. a

Ariciidae (listed thus by Vasquez—Montoya, 1979)

Naineris laevigata x
Naineris mutila x
Naineris setosa x
Scoloplos armiger x.

Chrysopetalidae (Palmyridae in B)

Bhawania goodei B, a, +
Bhawania riveti +
Cirratulidae
Cauleriella hamata x
Cauleriella sp. indet. B, a
Chaetozone sp. indet. B, a, y
Cirratulus cirratus ? in a, C. cirratulus in B
Cirriformia luxuriosa B, + (specimen in collection

from Pacific)

Cirriformia punctata Byway)

Dodecaceria concharum

Tharyx sp. indet.

Dorvilleidae
Dorvillea rubrovittatus

Driloneresis nuda

Schistomeringos longicornis

Eunicidae (Leodicidae in F)
Eunice afra
Eunice antennata aedificatrix
Eunice aphroditois
Eunice (Nicidion) cariboea
Eunice filamentosa
Eunice vittatopsis
Eunice websteri

Eunice sp. indet.

Lysidice ninetta
Lysidice sp.
Marphysa amadae
Marphysa depressa
Marphysa n. sp.
Marphysa sp. indet.

Nematonereis unicornis
Palola siciliensis

Palola sp. indet.

Flabelligeridae (Chloraemidae in B)
Pherusa capulata
Pherusa inflata

Piromis americana

Glyceridae
Glycera abranchiata

B, £74, a

a, D. rubrovittata in B

x
as x

i aa els, so
5 Elo oF

5 15 El5 wv
a, +, E. caribaea [sic] in B, F
lis Ele ae

Bieta sia

Bs a

ay x

WR tbo oe
Bera

Whe Gig oe

+ (no identifier on voucher

specimen)

Glycera oxycephala
Glycera tesselata

Glycera sp.

Goniadidae

Goniada acicula

Hesionidae

Hesione picta
Ophiodromus obscurus

Lumbrineridae

Lumbrineris inflata

Lumbrineris sp. aff. latreilli

Lumbrineris tetraura

Lysaretidae

Lysaretid sp.
Oenone fulgida

Maldanidae

Axiothella rubrocincta

Nereidae
Ceratonereis mirabilis
Neanthes galetae
Neanthes n. sp. 1
Neanthes sp. indet.
Nematonereis sp.
Nereis callaona
Nereis panamensis
Nereis n. sp. A
Nereis riisei
Nereis sp.

Nereidae sp. indet.

Lumbrinereis in B

a (in family Arabellidae in B)

Mp a, +

riseii [sic] in B, x

Perinereis elenacasoi
Perinereis anderssoni
Perinereis sp. indet. A
Perinereis sp. indet.
Platynereis dumerilii

Platynereis sp. indet.
Pseudonereis gallapagenesis

Onuphidae

Onuphis nebulosa
Onuphis vermillionensis

Onuphis sp.

Opheliidae

Armandia bioculata

Oweniidae

Owenia collaris

Paraonidae

Aricidea suecica

Phyl lodocidae
Anaitides erythrophyllus

Anaitides sp. cf. lamellifera

Eulalia myriacyclum
Sige orientalis

Poecilochaetidae

Poecilochaetus johnsoni

Polynoidae

Halosydna leucohyba
Halosydna sp. 1

B, a, x (in family Eunacidae in B)

B (in family Eunacidae in B)

a, erythrophylla [sic] in B

x
B, F, a, +
B

5 ie ali) G1

Harmothoe sp. indet.

Harmothoe hirsuta

Lepidonotus humilis
Lepidonotus neophilus
Lepidasthenia varius

Sabellariidae

Phragmatopoma sp. indet.
Sabellaria alcocki

Sabellaria floridensis

Sabellidae
news Spe
Demonax leucaspis
Demonax sp.
Hypsicomus torquatus
Hypsicomus phaeotenia
Megalomma sp.
Megalomma sp. aff. pigmentum
Megalomma roulei
Megalomma vesiculosum
Pseudopotamilla reniformis

Sabella melanostigma
Sabella sp. 17

Sabella sp. 18

Sabella sp.

Sabellidae sp. indet.
Sabellastarte magnifica

Serpulidae
Serpulid sp. 1
Serpulid sp. 2
Spirobranchus giganteus
Spirorbis sp.

B, a
B, + (specimen in collection

from Pacific)

B, a, +
B, a

? ina
B

+, B, F
a

a, Megaloma [sic] in B
B, a
B, a, +

B
y
a

5 3

Sigalionidae

Psammolyce spinosa B, a, =

Sthenelais verruculosa x

Spionidae
Boccardia polybranchia x
Malacoceros indicus x
Nerinides cantabra x
Prionospio cirrifera x
Prionospio heterobranchia

texana By al

Pseudopolydora antennata x

Syllidae

Autolytus anoplos
Autolytus n. sp.
Autolytus cf. magnus
Haplosyllis spongicola
Langerhansia cornuta
Langerhansia mexicana
Odontosyllis sp.
Opisthosyllis brunnea
Pionosyllis sp. indet. a

Syllidae, unident. fragments a

.
ry

.
+

ie8)
at,

ep eed eh ech eG
rub
S
oe

Le]
ie¥}
ab

Syllis longissima xX
Trypanosyllis taeniaformis X ¥;
Typosyllis aciculata B, a, + (specimen in collection

from Pacific)

Typosyllis fuscosuturata a
Typosyllis sp. A B
Typosyllis prolifera Bs 7 ania
Typosyllis variegata B

Terebellidae

Eupolymia nebulosa Bo WG Gly

Euthelepus pascua

Loimia medusa

Pista fasciata

Polycirrus sp.

Polycirrus sp. aff. haematodes

Streblosoma crassibranchia

Terebellidae sp. indet.
Thelepus setosus

Trichobranchidae

Trebellides stroemi

CRUSTACEA: COPEPODA (by order)
CALANOIDA

Unident. species

CRUSTACEA: ISOPODA (by family)
Anthuridae

Accalathura sp.?

Idoteidae

Cleantis planicauda

Cirolanidae
Cirolana parva
Excirolana mayana

Excorallanidae

Alcinora sp.

Excorallana tricornis

x
B, a, +

ARTHROPODA

Ligiidae

Ligia sp. y

Limnoriidae

Limnoria sp. y

Sphaeromatidae

Paracerceis caudata SS

Stenetriidae

Stenetrium serratum SS

CRUSTACEA: AMPHIPODA (by family)

Gammaridae

Elasmopus sp. y

CRUSTACEA: DECAPODA: REPTANTIA (by family)

Porcellanidae
Clastotoechus nodosus Wey el, ©
Megalobrachium poeyi B; JH, (e+
Megalobrachium roseum Bye Hin einact
Megalobrachium soriatum 5 dhly Gio a
Neopisosoma angustifrons es. sy =
Pachycheles chacei Bi Hee
Pachycheles cristobalensis Bi Hs er mets
Pachycheles serratus By JH eis), GA seat
Pachycheles susanae WS G5 Wa o
Petrolisthes armatus By JH) Chet
Petrolisthes galathinus aes MSs Gq sp
Petrolisthes jugosus By JH, "e, +

Grapsidae
Aratus pisonii EK, y

Goniopsis cruentata
Grapsus grapsus
Pachygrapsus gracilis
Pachygrapsus marmoratus
Pachygrapsus transversus
Percnon gibbesi

Plagusia depressa

Sesarma cinereum

Sesarma curacaoense

Portunidae

Callinectes sp.

Majidae
Acanthonyx petiverii
Epialtus sp.
= E. ?longirostris
Macrocoeloma subparallelum
Microphrys bicornutus

Mithrax acuticornis

Mithrax coryphe
Mithrax commensalis
Mithrax sculptus?

Mithrax spinossimus
Mithrax sp.

Mithrax verrucosus

Pitho aculeata

Stenorhynchus seticornis
Thoe puella

Xanthidae

Carpilius corallinus
Cataleptodius floridanus

Domecia acanthophora

Eriphia gonagra

JSG, + petriverii [sic] in B

JSG

By JSC

B, F, JSG, E74, E/5, E76, x, y, +
B, JSG

B, ISG, >

JRS, JS

RHG, Leptodium in B, JSG, LGA, +
8, ISG

B, JSG

Leptodius floridanus

Micropanope sp.

Panopeus be rmudensis

Panopeus harttii
Panopeus herbstii
Panopeus sp.
Panopeus sp. aff.

occidentalis
Paraliomera dispar
Pilumnus dasypodus
Pilumnus holosericus
Pilumnus lacteus
Pilumnus reticulatus
Pilumnus sayi?
Pilumnus sp.

Platyactaea setigera

Platypodia spectabilis

Xantho denticulatus

Calappidae
Calappa sp.

Gecarcinidae

Cardisoma guanhumi

Dromiidae

Dromidia sp.

Ocy podidae

Ocypode quadrata

Uca burgersi
Uca sp.

Palinuridae

Panulirus argus

Panu lirus guttatus

B, JoG

B, JSG, LGA
RHG, +

AKG hq Win ae
B, JSG

x
B, JSG, LGA, +

5 WiNG5 a:

B, JG, LEGAL e+

Biis Giauct

RHG, +

B, JSG

RHG, Actaea in B, JSG, +
By JSG, LGA, RHC.

RHG, Xanthodius in B, JSG, +

RHG

JC
JC

Scyllaridae
Scyllarus sp. JC

Parthenopidae

Heterocrypta macrobranchia? B, RHG

Leucosiidae
Uhlias limbatus B, JSG
Paguridae
Paguristes cadenati JC
Paguristes grayi PAA, m, +
Paguristes cf tortugae PAA, m, +
Pagurus bonairensis PAA, m, +
Pagurus brevidactylus PAA, m, +
Coenobitidae
Coenobita clypeatus PAA, m, +
Diogeniidae
Calcinus tibicen PAA, JH, m, +
Clibanarius antillensis PAA, m, +
Clibanarius sp. y
Clibanarius tricolor PAA, m, +
Dardanus venosus PAA, m, +
Dardanus sp. fo)
Petrochirus diogenes RHG, P. bahamensis in PAA, m, +
Petrochirus sp. fo)
Pinnotheridae
Pinnotheres maculatus JSG
Pinnixa ?faxoni JSG
Hapalocarcinidae

Pseudocryptochirus RHG

CRUSTACEA: DECAPODA: NATANTIA (by family)

Alpheidae
Alpheus armillatus Bienes

Alpheus armatus
Alpheus bahamensis

qa
Q

wo w

Alpheus cristulifrons
Alpheus floridanus

Alpheus formosus
Alpheus normanni
Alpheus nuttingi
Alpheus paracrinitus
Alpheus peasei
Alpheus ridleyi
Alpheus schmitti
Alpheus simus
Alpheus sp.

Alpheus viridari

Automate rectifrons

Metalpheus rostratipes
Salmoneus ortmanni
Synalpheus anasimus
Synalpheus brevidactylus RHG
Synalpheus fritzmuelleri B
Synalpheus herricki B
Synalpheus minus
Synalpheus pandionis
Synalpheus sp.
Synalpheus tenuispina
Synalpheus townsendi

Thunor rathbunae

ny
wm

no Dn woes weewtewneehwehweheOelekeOCUleOK
*

nT wD we DD

Callianassidae

Callichirus acanthochinus x

Gnathophyllidae

Gnathophyllum americanum

Hippolytidae

Hippolyte curacaoensis
Lysmata intermedia

Thor manningi

Palaemonidae

Periclimenes americanus

Stenopus hispidus
Stenopus scutellatus

Penaeidae

Penaeus duorarum

Penaeus sp.

Sicyonia parri
Trachypenaeus similis

Processidae

CRUSTACEA:

Ambidexter symmetricus

Processa bermudensis
Processa fimbriata

Processa sp. aff. hemphilli

STOMATOPODA

Gonodactylus austrinus
Gonodactylus bredini
Gonodactylus oerstedii
Gonodactylus spinulosus
Meiosquilla lebouri
Pseudosquilla ciliata
Nannosquilla sp.

nw ww

RM, B, y, +
RM, B, y, +
RM, B, y, +
HD and RS, +
RLC and RS
RM, x, y, +

CRUSTACEA: MYSIDACEA

Siriella chierchiae dd
Bowmaniella bracescui dd
Bowmaniella sewelli dd
Amathimysis cherados dd
Amathimysis gibba dd
Brasilomysis castroi dd
Cubanomysis jimenezi dd
Mysidopsis brattstroemi dd
Mysidopsis velifera dd
Mysidopsis arenosa sp. nov. dd
Mysidium columbiae dd
Mysidium gracile dd
Mysidium integrum dd

CRUSTACEA: CIRRIPEDIA

Balanus sp. ala
Balanus trigonus gg
Balanus venustus hh
Chthamalus angustitergum al
Chthamalus bisinuatus Val
Chthamalus rhizophorae 11
Chthamalus sp. y
Newmanella radiata Bg
Tetraclita stalactifera ia
PYCNOGONIDA
Achelia sawayai Bie Kat
Anoplodactylus allotrius kk
Anoplodactylus batangensis batangense in B, kk
Anoplodactylus evelinae B, kk, + (specimen in collection

from Pacific)

Anoplodactylus galetensis

Anoplodactylus insigniformis

Anoplodactylus jonesi
Anoplodactylus monotrema
Anoplodactylus multiclavus
Anoplodactylus pectinus
Anoplodactylus spp.
Anoplodactylus stri
Anoplodactylus trispinosus

Anoplodactylus viridintestinalis kk

Ammothella appendiculata

Ammothella exornata
Ammothella marcusi
Ammothella rugulosa
Ammothella spp.
Ammothella spinifera

Ascorhynchus castellioides
Ascorhynchus latipes
Callipallene emaciata
Callipallene sp.

Endeis spinosa

Eurycyde gorda

Eurycyde raphiaster
Eurycyde sp.

Nymphon floridanum

Nymphopsis duodorsospinosa

Pallenopsis schmitti
Pigrogromitus timsanus
Rhynchothorax architectus
Rhynchothorax sp.
Tanystylum birkelandi
Tanystylum geminum
Tanystylum isthmiacum
difficile

Tanystylum sp.

B, kk, +
kk, +

CAC, kk, +
B, kk, + (specimen in collection

from Pacific)

B, kk

MOLLUSCA
SCAPHOPODA
Dentalium gouldi KBM, +
Dentalium antillarum x
POLY PLACOPHORA

Acanthochitona hemphilli
Acanthochitona interfissa
Acanthochitona pygmaea

Acanthochitona spiculosus

Acanthochitona unident. sp.

Acanthopleura granulata
Calloplax janeirensis
Chiton viridis

Choneplax lata
Ischnochiton papillosus
Ischnochiton pectinatus
Ischnochiton purpurascens
Lepidochitona liozonis

COI oO Sse) ibs) bie Se ici eo esi ies

GASTROPODA: PROSOBRANCHIA

Acmaea antillarum B

Acmaea pustulata Bee
Alvania aberrans GB, +

Anachis catenata CBee Biemct

Anachis crassilabris F

Anachis obesa SIRS) CB

Antillophos sp. 1 CBanch

Architectonica nobilis KBM, +
Arene cruentata CB, B,

Arene tricarinata B

Astraea caelata DLW, B, +
Astraea phoebia KBM, IT, B, +
Bailya intricata B, F

Bailya parva KBM, +

Balcis intermedia B

Balcis sp. l B

Batillaria minima KBM, D, F, f£, y, +
Bittium varium B

Bursa cubaniana B

Bursa granularis KBM, +

Caecum sp. y

Calliostoma jujubinum KBM, +
Cantharus auritulus F

Cantharus tinctus

Cerithiopsis eme rsoni F

Cerithium eburneum KBM, B, £, x, +

Cerithium litteratum KBM, B, JR, £, x, y, + (cf. C litteratum
(Young) by CB in +]

Cerithium variabile B, D

Charonia variegata Bo Og @

Cheilea equestris B, Cheila [sic] in B

Cittarium pica B

Columbella mercatoria KBM, +

Conus daucus fo)

Comins wus) B

Coralliophila abbreviata KBM, +

Coralliophila aberrans CB, +

Coralliophila caribaea B

Crassispira fuscescens KBM, +

Crassispira leucocyma CB, +

Crassispira nigrescens JR

Crassispira tampaensis x

Crepidula plana B

Crucibulum auricula KBM, f£, +

Cyclostremiscus beaui B

Cymatium muricinum
Cymatium nicobaricum
Cymatium pileare
Cyphoma gibbosum
Cypraea cinerea
Cypraea zebra

Cypraecassis testiculus

Daphnella lymneiformis
Diodora cayenensis
Diodora dysoni

Diodora cf. minuta
Diodora variegata
Drillia albinodata
Drillia sp. lL

Drupa nodulosa
Emarginula phrixodes
Emarginula pumila
Engina turbinella
Epitonium candeanum
Epitonium lamellosum
Epitonium occidentale
Epitonium sp. l
Fasciolaria tulipa
Fissurella angusta
Fissurella barbadensis

Heliacus bisulcatus

Heliacus cylindricus

Heliacus infundibuliformis

Hemitoma octoradiata

Hemitoma sp.

Hipponix antiquatus
Hipponix subrufus
Hyalina albolineata

Hyalina avena
Hyalina tenuilabra

KBM, +
KBM, B, +
KBM, B, o, +
KBM, b, +
KBM, +

KBM, B05)

KBMS Bi. Ev7/O5nesn Oles

GBs Bt

Gis 15 ae

Olys Wo. dis “s

KEM Biy) JRen et

CBy JRG +

B, D, Morula nodulosa KBM, +

B
KBMo Be One Xouct

,» infunibuliformis [sic] in F

KBM, B, F, x, +
B

Janthina janthina KBM, +

Latirus carniferus RB, KBM, JR, +, carnifera [sic] in B
Latirus distinctus y

Latirus infundibulum fo)

Leucozonia nassa RB, +

Leucozonia ocellata KBM, B, +
Littorina angulifera KBM, y, +
Littorina angustior JC, (KBM, + as L. lineata)
Littorina lineolata B, D

Littorina meleagris D

Littorina nebulosa KBM, y, +
Littorina tessellata KBM, +

Littorina ziczac KBM, D, +

Lucapina suffusa KBM, +

Mangelia fusca B, +

Marginella gracilis x

Melongena melongena KBM, x, +
Melongenidae sp. fo)

Mitra nodulosa KBM, +

Mitra sp. B

Modulus modulus KBM, B, f£, +
Morula nodulosa see Drupa nodulosa
Morum oniscus KBM, o, +

Murex dilectus KBM, +

Murex pomum KBM, KBM, o, +
Murex recurvirostris rubidus KBM, G, GLH, +

cf. Murex woodringi KBM, +

Nassarius vibex KBM, F, x, +
Neosimnia acicularis G3,

Nerita fulgurans KBM, D, +

Nerita peloronta KBM, D, +

Nerita tessellata KBM, D, y, +
Nerita versicolor KBM, D, +

Neritina virginea DLW, KBM, JR, f, x, y, +, virgines

[sic] in F, virginica [sic] in f

Nitidella nitida
Nitidella sp. 2

Nodilittorina tuberculata

Oliva reticularis

Olivella petiolita
Opalia crenata
Opalia pumilio

Petaloconchus sp.
cf. erectus
Pisania pusio
Planaxis lineatus
Planaxis nucleus

Polinices hepaticus

Polinices lacteus

Prunum gut tatum

Psarostola monilifera
Purpura patula
Risomurex muricoides
Risomurex roseus
Risomurex sp.
Rissoina bryerea
Rissoina decussata
Rissoina multicostata

Smaragdia viridis
Strombus gigas

Strombus pugilis
Strombus raninus
Tectarius muricatus
Tegula fasciata

Thais deltoidea

Thais haemastoma, var A
Thais haemastoma

Thais rustica

Tonna maculosa

Tricolia adamsi

KBM, D, +

KBM, +

DLW, +

CB, BB, +

B, pumilo [sic] in B

Onnex
KBM, B, + lactens [sic] in f
KBM, JR, +

KBMS Bion

KBM Be JR +

SRY sea tee

Bi in Xs ck

KBM, D, +

KBMin Bis Reet
35 DIRS Oo

GB Bs Diy JR
fo)

fo)

KBM, +

DLW, KBM, B, +

Tricolia bella KBM, CB, B, F, +

Tricolia thalassicola KBM, +

Trivia quadripunctata DLW, KBM, JR, +
Turritella exoleta KBM, +

Vasum muricatum DLW, B, +
Vermetidae y

Voluta musica DLM, +

GASTROPODA: OPISTHOBRANCHIA (by order)

Anaspidea
Aplysia dactylomela EK, KBM
Aplysia parvula KBM
Aplysia sp. KBM
Bursatella leachii pleii EK, y, KBM
Dolabrifera dolabrifera KBM
Petalifera ramosa KBM
Phyllapylsia engeli KBM
Stylocheilus longicauda KBM
Cephalaspidea
Aglaja evelinae KBM
Atys riiseana x
Bulla occidentalis KBM, x
Bulla striata KBM, f, +
Chelidonura spp. KBM
Haminoea antillarum x
Haminoea elegans KBM
Ildica sp. KBM
Micromelo undata DS, SW, KBM
Sacoglossa
Bosellia marcusi KBM
Bosellia memetica KBM

Caliphylla mediterranea KBM

Cyerce antillarum

Elysia ornata
Elysia papillosa
Elysia picta

Elysia tuca
Lobiger souverbii

Oxynoe antillarum
Placida dendritica

Phyllobranchillus sp.
Stiliger sp.
Tridachia crispata

Notaspidea

Berthella tupala
Berthellina quadridens

Pleurobranchus areolatus

Nudibranchia

Aegires sublaevis
Aphelodoris antillensis
Berghia coerulescens
Berghia creutzbergi
Bornella calcarata
Cadlina rumia
Catriona tina
Chromodoris clenchi
Chromodoris kempfi
Chromodoris sp.
Coryphella dushia
Dendrodoris krebsii
Discodoris evelinae
Discodoris mortenseni

Dondice occidentalis

KBM
KBM
KBM
KBM
KBM
KBM
KBM
KBM
KBM
KBM
KBM, +

Doriopsilla nigrolineata h
Doto divae KBM
Felimare bayeri h, KBM
Glaucus atlanticus KBM
Godiva rubolineata KBM
Hexabranchus sanguineus h, KBM
Hypselodoris ruthae h, KBM
Okenia evelinae h, KBM
Phidiana lynceus KBM
Phyllidiopsis molaensis h
Platydoris angustipes h
Scyllaea pelagica KBM
Spurilla neopolitana KBM
Tambja oliva h, KBM
Tritonia bayeri KBM
Tritonia wellsi KBM

GASTROPODA: PULMONATA

Melampus coffeus KBM, +
BIVALVIA
Americardia media x
Anodontia pectinata x
Anomia simplex DLW, JR, +
Arca imbricata It, sl, I, O54 sp
Arcopsis adamsi ET, Bao kiseks! Xie
Asaphis deflorata KBM, +
Barbatia domingensis G3, By =
Barbatia tenera BM, B, +
Brachidontes modiolus JR
Brachidontes citrinus B
Brachidontes exustus F, exhustus [sic] in ii, y

Brachidontes recurvus B

Brachidontes sp.
Chama macerophylla
Chione cancellata
Chlamys imbricata
Codakia costata
Codakia orbicularis

Codakia orbiculata

Codakia pectinella
Coralliophaga coralliophaga

Corbula caribaea

Corbula contracta

Corbula cubaniana
Crassinella martinicensis
Crassinella lunulata
Crassostrea rhizophorae
Crassostrea sp.

Ctena orbiculata

Cumingia antillarum
Cyathodonta semirugosa
Diplodonta punctata
Diplodonta semiaspera

Donax denticulatus

Echinochama arcinella

Erycina emmonsi
Erycina periscopiana
Gastrochaena hians

Gouldia cerina

Gregariella coralliophaga
Isognomon alatus
Isognomon bicolor
Isognomon radiatus
Laevicardium laevigatum
Lima pellucida

Lima scabra

Lima scabra form tenera

jj
KBM, B, +

sue
5 Jats! a

B
B
B, F, £, x, (as Ctena insite
x
B

» ts +

Lioberus castaneus B

Lithophaga antillarum KBM, f, +

Lithophaga bisulcata B34 I, i

Lithophaga nigra 5 Wo Ie

Lucina leucocyma x

Lucina pensylvanica B

Macoma constricta x

Macoma tenta B

Modiolus americanus KBM, B, +

Musculus lateralis JR, £, +

Ostrea equestris DLW, JR, +

Phacoides muricatus x

Phacoides pectinatus KBM, CB, B, F, ii, +

Pinctada radiata KBM, B, F, +

Pinna carnea JR, +

Pseudochama arcinella B

Pteria colymbus DLW, KBM, JR, +

Sphenia antillensis B, +

Spondylus americanus SW

Solemya sp. aff. occidentalis x

Strigilla sp.

Tellina alternata Li

Tellina exerythra x

Tellina fausta DLW, JR, £, x, +

Tellina listeri x

Tellina nitens x

Tellina promera ii

Tellina versicolor x

Tellina vespusiana x

Teredo sp. ¥

Trachycardium muricatum DLW, +

Venericardia sp. aff. tridentata x
CEPHALOPODA

Octopus sp. E75, K

ECTOPROCTA (BRYOZOA)

Arborella dichotoma JDeet
Bugula sp. y
Caberea carabaoda JD eet
Caulibugula dendrograpta SDS se
Celleporaria albirostris IDS ae
Chlidonia pyriformis JD
Gemillipora sp. y
Gemelliporidra multilamellosa JD eeaaeect
Lichenopora buskiana JID,
Retoporelliria evelinae JD
Steganoporella magnilabris IDF alate
Stylopoma informata IDE
Trematooecia aviculifera JD; aay +
Trematooecia turrita JD, 225
Tubucellaria cereoides JD, +
BRACH LOPODA
Discinisca strigata B, + (specimen in collection
from Pacific)
ECHINODERMATA
(by class)
ECHLNOLDEA

Arbacia punctulata DLM, +
Brissopsis elongata DLM, +
Brissus unicolor DEMG) Bis Bi7iGy Kemet
Diadema antillarum B, B74, E75, E76, Ky) (Ol vane

Echinometra lucunter NVA VSG NIA s Ms Og 3

Echinometra viridis B, E74, E75, E/6, k, o

Echinoneus cyclostomus B, E76, k, +

Eucidaris tribuloides DLM, B, E/6, k, 0, y, +

Halodeima floridana x

Lytechinus variegatus DLM, B, E74, E75, E76, k, 0, p,
x Yor

Lytechinus williamsi DIM, +

Meoma ventricosa DLM, +

Paraster floridiensis DLM, E76, k, +

Plagiobrissus grandis DIM, +

Tripneustes ventricosus DLM, E76, k, v, x, +,

T. esculentus in B

ASTEROLIDEA
Ophidiaster guildingii B
Oreaster reticulatus DLM, B, +
OPHIUROLDEA

Amphiodia repens B
Amphiodia sp. L B
Amphipholis sp. A B
Amphipholis sp. B
Amphipholis gracillima x
Amphiura (Monamphiura) sp. B
Amphiura (Nullamphiura) sp. B
Axiognathus squamata B
Ophiactis savignyi DLM, B, x, +
Ophiocantha ophiactoides B
Ophiocoma echinata DIM, B, +
Ophiocoma pumila DLM, B, +
Ophiocoma sp. y/
Ophiocoma wendti DIM, B, +

Ophioderma appressum DIM, B, y, +

Ophioderma brevicaudum DIM, BS
Ophioderma brevispinum DLM, B, +
Ophioderma cinereum DIM, Bo-+
Ophioderma rubicundum DLM, +
Ophiolepis paucispina DEM, Bite
Ophiomyxa flaccida DIM, +
Ophionereis reticulata DEM, B, +
Ophiothrix angulata DLM, B, +
Ophiothrix cf. lineata DLM, +
Ophiothrix suensonii DLM, +
Ophiozona impressa DLM, +
Ophiozonoida (?) sp. B (this may be new genus; EK,
pers. comm.)
CRINOIDEA
Comactinia echinoptera DLM
Comactinia echinoptera:
cf. var. valida cc

Comactinia echinoptera ci. var.

meridionalis cc
Comactinia meridionalis DLM, +
Nemaster rubiginosa cc
Nemaster discoidea cc

HOLOTHUROIDEA
Euapta lappa JC
Holothuriid sp. JC
CHORDATA

ASCIDICEA

Ascidia interrupta DS

Clavelina sp. y

Clavelina picta RHM
Cystodytes dellechiajei RHM
Didemnum spp. DS

Didemnum sp. B RHM
Didemnum sp. C RHM
Didemnum sp. D RHM
? Didemum sp. E RHM
Distaplia (? bermudensis) RHM

Ecteinascidia conklini var.

minuta DS
Ecteinascidia turbinata RHM
Eudistoma sp. A RHM
Eudistoma sp. B RHM
Pyrua vittata DS
Polysyncraton (? amethysteum) RHM
Rhopalaea abdominalis RHM
Trididemnum cyanophorum

(= T. solidum) RHM, RO, v, w
Trididemum sp. A RHM

NOTE: RHM identifications are provisional.

ACKNOWLEDGMENTS

We thank the following people for their assistance in preparing this
species inventory: Victoria Batista, Charles Birkeland, Edwin Bourget,
Leo Buss, Roy Caldwell, Hugh Dingle, Kristian Fauchald, Joan Ferraris,
Robert H. Gore, Eugene Kaplan, Arilla Kourany, Haris Lessios, David Meyer,
Kaniaulono Meyer, Randy Olson, James Porter, Klaus Ruetzler, Michael
Robinson, Argelis Roman, Joseph Rosewater, Kenneth Sebens, Stephen Shuster,
Richard Steger, and Janie Wulff.

This study was supported by the Smithsonian Institution Environmental
Sciences Program and the Smithsonian Tropical Research Institute.

LITERATURE CITED

Abele, Lawrence G. 1972. A review of the genus Ambidexter (Crustacea:
Decapoda: Processidae) in Panama. Bull. Mar. Sci., 22(2): 365-380.

Abrams, Peter A. 1976. Field guide to the hermit crabs of Galeta and
vicinity. Smithsonian Tropical Research Institute. 4 p. (with
subsequent revisions by PAA) unpubl.

Batista, Victoria. 1980. Estudio de las comunidades que habitan las
raices del mangle rojo Rhizophora mangle L. de Punta Galeta, Costa
Atlantica de Panama. Dissertation. Fundacion Universidad de
Bogota Jorge Tadeo Lozano, Bogota, Colombia.

Bertsch, Hans. 1975a. Distributional and anatomical observations of
Berthella tupala (Opisthobranchia: Notaspidea). The Nautilus,
89(4): 124-126.

Bertsch, Hans. 1975b. Additional data for two dorid nudibranchs from
the southern Caribbean seas. The Veliger, 17(4): 416-417.

Birkeland, Charles. 1974. The effect of wave action on the population
dynamics of Gorgonia ventalina Linnaeus. Studies in Tropical
Oceanography, 12: 115-126.

Birkeland, Charles, Amada A. Reimer and Joyce Redemske Young. 1976.
Survey of marine communities in Panama and experiments with oil.
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ATOLL RESEARCH BULLETIN
No- 270

HERMATYPIC CORAL DIVERSITY AND REEF ZONATION AT CAYOS ARCAS,
CAMPECHE, GULF OF MEXICO

TERENCE M- FARRELL, CHRISTOPHER F- D’ELIA, LAWRENCE

LUBBERS, III, AND LAWRENCE J- PASTOR, JR-

ISSUED BY
THE SMITHSONIAN INSTITUTION
WASHINGTON, D- C-, U-S-A.-

SEPTEMBER 1983

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HERMATYPIC CORAL DIVERSITY AND REEF ZONATION AT CAYOS ARCAS,
CAMPECHE, GULF OF MEXICO

by Terence M. Farrell!/3, Christopher F. Deal,
Lawrence Lubbers, eseae U and Lawrence J. Pastor, Jr.274

‘Abstract

Ecological features of emergent coral reefs in the Campeche Bank
region of the Gulf of Mexico are not well described. In a study of reef
zonation and diversity of CayosS Arcas, the most southerly of these, the
coral reefs surrounding three sand cays were found to exhibit a greater
diversity of scleractinian coral species than has been reported
previously for the Campeche Bank region. Hermatypic coral coverage was
high and coral growth appeared vigorous. However, calcareous algae of
the genus Halimeda, that are known to be abundant and therefore
important producers of calcareous material in emergent reef structures
to the north, were not evident. Noteworthy aspects of reef zonation
included: 1) a non-emergent reef crest composed of unconsolidated coral
rubble and encrusting calcareous algae, but no algal ridge, 2) extensive
monospecific stands of Acropora cervicornts on the shallow reef flats,
3) proliferation of Acropora palmata at depths where one might
typically find Acropora cervicornis in other localities, and 4) poor
representation and coverage by species of the genus Agartcta. This
zonation and the component species" growth forms suggest that high
energy wave action is an important environmental factor determining
community structure.

Introduction

Relatively few published reports relate to the species composition
and ecology of recent bioherms in the Gulf of Mexico. One reason for
this is that the Gulf of Mexico does not contain extensive areas of
coral reef. Nonetheless, in addition to the reefs off of Veracruz
(Smith, 1954) there are six well developed emergent reef structures in
the Campeche Bank region off of the western shore of the Yucat4n
Peninsula (Glynn, 1973; Logan, 1969). The largest and most northerly of
these is Alacran Atoll which has been the site of several geologically
oriented studies (Hoskin, 1963; Kornicker et al., 1959; Kornicker and
Boyd, 1962; Folk, 1967). The others are less well known, but have been

1Chesapeake Biological Laboratory, Center for Environmental and
Estuarine Studies, University of Maryland, Solomons, Maryland
20688-0038.

2Virginia Institute of Marine Science, Gloucester Point, Virginia 23062
3Present Address: Zoology Department, Oregon State University 97331
4present Address: Water Chemistry Division, Geomet Technologies, Inc.,
Environmental Consultants, 520 Eroadhallow Road, Melville, New York
11747

Contribution No. 1377. Center for Environmental and Estuarine Studies
of the University of Maryland.

Manuscript received Jan. 1983--Eds.

described to some extent (Agassiz, 1888; Logan et al., 1969).

We visited on two occasions the most southerly of the Campeche reef
structures, Cayos Arcas. The cays comprising this structure are at the
northern boundary of Mexico's offshore petroleum resources, and a
deepwater oil terminal has been built in the sheltered waters south of
the cays since our last visit (Orme, 1982). In the course of performing
an environmental survey focusing on reef development and zonation, we
found well-developed reefs with greater diversity of hermatypic corals
than has been reported previously for the Campeche Bank region. In the
present paper we document and discuss these and other relevant
ecological observations.

Study Site

Cayos Arcas consists of three coral and sand cays on a shallow
water platform about 3 to 4 sq. km. in area which rises above the
Campeche Bank west of the Yucat&n Peninsula, Mexico (Fig. 1). Water
depth around the cays is about 40 m. The cays envelop a small,
protected lagoon that is a popular refuge for local shrimp and shark
fisherman located at 91° 58'30"E long. and 20° 12'55"N lat., about
300 km SW of Alacran Atoll.

Logan et al. (1969) and Ginsbu:rg and James (1974) have
characterized Cayos Arcas and neighboring reefs and cays as isolated
praminences capped by zoned reefs at the shelf margin. Kornicker and
Boyd (1962) have described the geological origin of the Campeche Bank as
an “underwater extension of the Yucatan Peninsula... [that is] probably
Miocene limestone" with a thin cover of Pleistocene and Recent
calcareous sediments. Campeche Bank reefs have apparently been able to
keep pace with the Holocene transgression; this implies that reef
accretion there occurred at the substantial rate of 20 to 40m during the
last 9,000 years (Logan, 1969) or perhaps faster: more recently
Mcintyre et al. (1977) proposed that Yucatdn reefs have approached the
emergent-reef status within the last 2,000 to 3,000 yrs. In any case,
it is clear that accretion is rapid on the Yucatan reefs.

Easterly to northeasterly trade winds prevail and probably account
for the typical northwest trend of arcuate windward reef margin
characterizing Cayo del Centro (Fig. 1). Such reef orientation has been
reported for other bioherms on the Campeche Bank (Kornicker and Boyd,
1962; Folk, 1967). Fram April to September, winds in the area are
lighter and more variable (20 to 30 km/hr) than they are from October to
March when speeds of 30 to 35 km/hr are cammon and are often associated
with cold fronts or "northers" (Folk, 1967). Hurricanes are not
uncommon to the area, Hurricane Allen having passed several hundred km
to the north of Cayos Arcas several months before we performed our
Survey- The tidal range is small (~1.0 m). We do not have mean minimum
water temperature for Cayos Arcas; however, we suspect it is between 20°
and 22° C, close to those reported for nearby Veracruz and Progresso,
Mexico (Milliman, 1973) and by the U. S. Fish and Wildlife Service
(1954). Thus reefs at Cayos Arcas probably experience mean minimum

temperatures near 21°C, below which optimal reef development does not
occur (Milliman, 1973). Glynn (1973) reports that the thermal climate
of the reefs on the margin of the Campeche Bank is probably more
favorable than it is closer to shore, citing the suggestion of Logan et
al. (1969) that the absence of coral reefs on the eastern sector of the
shelf is due to the periodic upwelling of cold water there.

Surveys of the coral community were carried out by skin and SCUBA
diving. We used a transect method keyed to changes in depth and
distance offshore and selected a major topographical feature, i.e.,
beach, reef crest, deep trench as a benchmark for the starting point for
a compass bearing traversing various zones of the benthic community. We
chose the transects as being generally representative of reef zonation
at Cayos Arcas.

A check list of the most abundant sessile invertebrates (primarily
hermatypic corals) was developed after an intensive survey of the first
transect. At this site a 30 m long chain marked at one meter intervals
was laid on the bottom starting at the reef crest and moving towards
deep water. We noted species composition and dominance within ten
meters of this chain and estimated the total percent living coverage,
depth in meters and any significant changes in topography or coral
composition with distance from the starting point. Aerial photographs
of the transects taken from a helicopter at an altitude of about 200 m
were used to confirm our estimates of percent coverage and the
representativeness of the transects chosen.

Results

Table 1 gives a summary list including all coral species identified
in all five transects during our study. The list contains 20 species we
identified and 5 species we suspect were present and is certainly
indicative of the most common corals in the shallower (<20 m) zones of
the reef. Had the study lasted longer and extended to deeper areas,
more species would undoubtedly have been found (see Discussion). In
fact, it would be surprising if species reported by Smith (1954) to be
present off Veracruz are not also present at Cayos Arcas (Table 1).
Observations along transects were completed at 5 locations (Figure 1).
These data have been summarized in graphic form (Figure 2).

The most developed reef at Cayos Arcas, in terms of physical
structure and coral coverage, occurs as a three kilometer long, arcuate
structure to the northwest of the central cay (Figure 1). This reef can
be seen in the upper right portion of Plate 1, an aerial photograph
viewing Cayos Arcas from the southeast. We investigated reef flat and
lagoonal areas of this reef in Transect 2. Transect 1 encompassed the
reef crest and fore reef of a nearby section of reef that was similar in
physical and biological structure to the fore reef area along arcuate
reef face (Plate 2). Taken together Transect 2 and the fore reef
section of Transect 1 provide a good picture of the main biological and
structural zones occurring on the major Cayos Arcas reef.

The most obvious feature of the reef was an extensive reef flat,
over 100 meters wide, almost completely covered by a dense, monospecific
stand of Acropora cervicornis. To the lee of this stand the bottom
gradually sloped from less than one meter to three meters. On this
slope a more diverse assemblage of hermatypic corals existed
(predominantly members of the genera Acropora, Montastrea, and
Diploria), in which substratum coverage ranged fran 20-60% and decreased
with distance from the reef flat. This back reef area gave way to sandy
substrata in the lagoon that harbored numerous patch reefs not crossed
by the transect.

To the windward side of the reef flat a small, non-emergent reef
crest existed. The crest was composed of unconsolidated coral rubble
encrusted with calcareous red algae. No true algal ridge was present.
On the forereef the zoanthids Palythoa caribbea and Zoanthus sociatus
were the daminant epibenthic fauna between one and three meters. Below
this zoanthid zone, at depths between three and seven meters, Acropora
palmata was the dominant scleractinian, covering nearly 75% of the
substratum (Plate 3). Massive corals, dominantly the genera Montastrea
and Diplorta and gorgonians were abundant below seven meters
(Plates 4 and 5) in a diverse community extending to approximately 350
meters fram the crest, and to a depth of 18 meters where sand substratum
was again encountered.

To the lee of the reef crest in Transect 1 the reef flat was absent
and the back reef area consisted of a shallow (one meter) expanse of
sandy substratum in front of the largest cay, in which scleractinians
were scarce.

Transect 3 crossed a nearby, small, protected reef. Its zonation
pattern was very similar to the previously discussed larger, exposed
reef but it lacked a reef crest and its zonation was both horizontally
and vertically compressed.

The remaining two transects were completed at each end of the
largest reef. Transect 4, located at the more protected southern end,
displayed zonation that was similar to the exposed forereef, except that
it was horizontally compressed so that the Montastrea - Diplorta
canmunity occurred in water several meters shallower than it did on the
windward face of the reef. Transect 5, located at the northwestern end
of the reef, traversed an eight meter deep channel that curved around
the edge of the reef flat. In this channel the bottom was composed of
unconsolidated coral rubble and sediment. The face on the far side of
the channel rose to within three meters of the surface. Benthic cover
on top of this rise was daminated by the zoanthid Palythoa cartbbea.
Species distributions on this crest and the slope beyond it were similar
to those seen on the exposed reef face. However, the slope was more
gradual and coral coverage was more extensive. Substratum coverage was
70 to 90% beyond 500 m at a depth of 20 m.- Here was one of the few
places we observed extensive growth of Acropora cervicornis below three
m depth: a 30 m wide stand occurred at 8 m depth.

Four transects were located on the large arcuate reef. From these
transects and less detailed observations made from a helicopter, the
distribution of major reef zones on the reef have been mapped (Figure
3).

Discussion

The hermatypic scleractinian coral diversity of Cayos Arcas
consists of at least 20 species from 13 genera. This diversity is
greater than is believed to exist off Veracruz or has been reported for
Alacran Reef: for the former there are records of 14 to 16 species and
for the latter there are records of 18 species (Glynn, 1973). Given the
geographical isolation of this site, this diversity seems surprisingly
high, but is not, of course, as high as has been recorded in Jamaica
(Wells, 1973), in Curacao (Bak, 1974; cited in Loya, 1976), in Cuba
(Zlantarzsky, cited in Loya, 1976), in Belize (Cairns, 1982), and on the
Atlantic coast of Panama (Porter, 1972). Relatively little is known
about reefs in the southern Gulf of Mexico, but we believe that
nearshore turbid water conditions and a lack of suitable substratum
affect growth; it is also likely that minimum winter temperatures are
close to the lower limits at which extensive reef growth may occur,
especially near the coast where occasional upwelling is believed to
occur (cf. Logan et al., 1969). It is possible that seasonal
temperature lows exclude species unable to tolerate them; however, the
presence of species of the genus Acropora, which are unable to tolerate
the colder temperatues encountered in Bermuda, indicates that minimum
temperatures are considerably higher than in Bermuda.

Our field work was most extensive in shallow water; additional
study in deeper waters could most probably increase the number of
species found. Loya (1976) has discussed the increase in known species
richness which occurred with increasing study in other areas.

Logan (1969), who made the only published ecological observations
on Cayos Arcas that we encountered, made generally similar observations
to ours about community structure. However, Logan (1969) did not report
seeing the presence of a very dense monospecific stand of Acropora
ecervicornts on the shallow reef flat as we note here. Similar zonation
is also found off Belize (Cairns, 1982) and off the east coast of the
Yucatan peninsula (W. Adey, J. W. Porter, pers. comm.). There is no
doubt that Logan (1969) would have recognized and cammented on that
impressive stand of Acropora had it been present during his study. We
cannot explain this difference, but suspect that a real change in
community structure occurred in the interim.

Neither we nor Logan (1969) observed calcareous green algae of the
genus Halimeda- This observation was unexpected as Halimeda is
extremely common on the nearby Alacran reef (Hoskin, 1963; Kornicker and
Boyd, 1962). We searched for this coralline algae but did not encounter
living Halimeda nor obvious skeletal remains. however, we were unable
to examine sediments microscopically to verify our field observations.
Haltmeda is the dominant producer of carbonate sediments on a reef off

Belize (Wallace et al., 1977) and presumably Alacran (Hoskin, 1963).
Its absence at Cayos Arcas may result in lowered rates of calcium
carbonate deposition.

High wave energy levels may account for some of the species
distributions observed on these reefs (Logan, 1969). The depth to which
the forereef Palythoa and Acropora palmata dominated zones extended, and
the lack of Acropora cervicornis and members of the genus Agaricia on
the forereef is probably a result of intense wave action during storms.
In backreef areas, where lower wave intensities predominate, the
zonation was compressed so that the coral-head communities existed
closer to the water surface.

Our observations indicate that well developed reef communities
exist at Cayos Arcas. These communities contain the most diverse
hermatypic coral assemblage found to date on the western Yucatan shelf.
Further investigation will be necessary to determine if this apparent
difference in diversity is real or due to the limited study most other
locations in this region have received. However, we suspect that coral
diversity throughout the area is richer than it is generally perceived
to be. A continuing environmental monitoring program was instituted
before the construction of the oil terminal, and further studies to
assess the ecological impact of the facility have been discussed by Orme
(1982).

References

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Steamer "Blake": Harv. Mus. Comp. Zool., 14:70-73.

Cairns, S.- De 1982. Stony corals of Carrie Bow Cay, Belize, pp.
271-302. In: Rutzler, K., and I. G. Macintyre, eds., The Atlantic

Barrier Reef Ecosystem at Carrie Bow Cay, Belize, I. Structure and
communitteg. Smithsonian Institution Press. Washington, D.C.

BOK ie een lars 1967. Sand cays of Alacran Reef, Yucatan, Mexico:
Morphology- J, Geol. 75:412-437.

Ginsburg, R. N-, and James, N.- Pe 1974. Spectrum of Holocene
reef-building communities in the Western Atlantic. Section 7 of
"Prinetples of Benthie Comminity Analysts," Zeigler, A. M., Ks. Re
Walker, E. J. Anderson, E- G. Kaufman, R. N. Ginsburg, and N. P.
James, contributors. Div. of Mar. Geol. Geophys. RSMAS.
University of Miami, Fla.

Glynn, P. W. 1973. Aspects of the ecology of coral reefs in the
Western Atlantic region, pp. 271-324. In: Jones, O. A., and Re
Endean, eds., Biology and Geology of Coral Reefs, Vol. II.,
Academic, N.Y.

Hoskin, G. M- 1963. Recent carbonate sedimentation on Alacran Reef,
Yucatan, Mexico, NAS-NRC. Publ. 1089:1-160.

Kornicker, L. S., and Boyd, D. We 1962. Shallow water geology and
environments of Alacran reef complex, Campeche Bank, Mexico. Am.
Assoe. Petrol. Geol. Bull. 46:640-673.

Kornicker, L. S., Bonet, F., Cann, Re, and Hoskin, C. M. 1959. Alacran
Reef, Campeche Bank, Mexico. Univ. Texas Publ. Inst. Mar. Sct.
6:1-22.

Logan, B- We 1969. Coral reefs and banks: Yucatan shelf, Mexico.
Mem., Am. Assoc. Petrol. Geol. 11:129-198.

Logan, B. W., Harding, J-e Le, Ahr, We Me, Williams, J. D., and
Snead, R. G. 1969. Carbonate sediments on reefs, Yucatan shelf,
Mexico, Part I, Late Quaternary sediments. Mem., Am. Assoc.
Petrol. Geol. 11:1-128.

Loya, Y. 1976. Effects of turbidity and sedimentation on the community
structure of Puerto Rican corals. Bull. Mar. Set. 26:450-466.

Macintyre, I. G., Burke, Ro Be, and Stuckenrath, R. 1977. MThickest
recorded Holocene reef section, Isla Perez core hole, Alacran Reef,
Mexico, Geology. 5:749-754.

Milliman, J. D. 1973. Caribbean coral reefs, pp. 1-50. In: Jones,
O. A., and R. Endean, eds., Biology and Geology of Coral Reefs,
Vol. I- Academic, N.Y.

Orme, We A., Jr- Cayo Arcas: New Oil Port 70 Miles Offshore. R & D
Mextco. Vol. 2, Noe 11:22-25.

Porter, J. W. 1972. Patterns of species diversity in Caribbean reef
corals. Ecology 53:745-748.

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Table 1. Hermatypic scleractinian coral species occurring at Cayos
Arcas. "?" indicates probable identification. '"*" indicates species
reported found at Cayos Arcas by Logan et al. (1969) that we did not
encounter. Species in parentheses were reported present at Veracruz by
Smith (1954) are probably also present, but we did not observe them at
Cayos Arcas in our survey.

Suborder Astrocoeniida
Family Pocilloporidae
Madracis decactis
Family Acroporidae
Acropora palmata
Acropora cervicornts
Suborder Fungiida
Family Agariciidae
Agaricta agaricites
Family Siderastreidae
Siderastrea siderea
Siderastrea radtans
Family Poritidae
Porites asterotdes
Porites porttes
(Porites furcata)
Suborder Faviida
Family Faviidae
Favta fragun
Diplorta eltvosa
Diploria labyrinthiformts
Diploria strigosa
Colpophyllta natans
Colpophyllia brevisertalis
Montastrea annularts
Montastrea cavernosa
Solenastrea sp-*
Manietna areolata
(Cladoeora arbuscula )
Family Meandrinidae
Meandrina meandrites
Diehoecoenia strokest ?
Family Mussidae
Mussa angulosa
Mycetophyllta lamarekiana
Family Oculinida
(Oculina diffusa )
Suborder Caryophylliina
Family Caryophylliidea
Eusmilta fastigtata

DEPTH (meters)

TRANSECT 1 Palythoa
al Sand/Rubble tn, palmata—>|

Montastrea-Diploria——\>|+ Sand/Rubble—

12
18)

TRANSECT 2
; |-——A. cervicornis ——~|=~—— Montastrea—Dipioria —~l<- Sand/Rubble —>

3
100 200 300 400
TRANSECT 3 A. cervicornis Palythoa

|Montastrea-Diploria}~—l ++ 1 1p. paimata|<—-Montastrea-Dipioria—>|
0
3
6
9

TRANSECT 4
Palythoa-A. cervicornis

|sand/Rubbiel-—_! —-| Montastrea—Diptoria |<— Sand/Rubble

200 300

100

100 200 300 400

12
TRANSECT 5

Montastrea-Diploria | Montastrea-Diploria
Serafsbiele! la

Palythoa-A. paimata A. cervicornis
|<—Montastrea-Diploria——>

METERS

Fig. 2. Transect profiles at Cayos Arcas.

meee ) Ye ae ihe: (eigan JB409) ySaID yaoy
OP ale ), Esueuipagresoo7 ||

Aerial view of the Cayos Arcas from the southeast

Hae
i

HH)

maligne

entral cay and the reef viewed from

Plate 2. Aerial photograph of the c
the east

Plate 3. Underwater photograph of the Acropora palmata zone on Transet l.
Taken at approximately 4 m depth

eet

EME

-v teased

oak

“ar

ween =
ete

Plate 4. Photograph of the Montastrea-Diploria zone taken in water 10 m
deep (Transect 1)

Plate 5. Photograph of the Montastrea-Diploria zone taken in water 10 m
deep (Transect 1)

ATOLL RESEARCH BULLETIN
No- 271

CAY SAL BANK, BAHAMAS: A BIOLOGICALLY IMPOVERISHED, PHYSICALLY
CONTROLLED ENVIRONMENT

WALTER M-GOLDBERG

ISSUED BY
THE SMITHSONIAN INSTITUTION
WASHINGTON, D- C-, U-S-A-

SHRP MBE Rwend63

CAY SAL BANK, BAHAMAS: A BIOLOGICALLY IMPOVERISHED
PHYSICALLY CONTROLLED ENVIRONMENT

by Walter M. galdeeres-

ABSTRACT

Cay Sal Bank is a shallow water, oceanic platform whose
lagoonal surface is 9-l6m below sea level. Benthic
communities on the bank are divided into four major zones
based upon biotic composition and substrate. These are (1)
rubble- Lobophora (2) Sargassum-gorgonian-sponge (3) Halodule
and associates and (4) a patchy Thalassia zone. Sediment
is largely restricted to the western portion of the lagoon,
especially in zone 3. Although occasional patch reefs are
noted, the bank lagoon is virtually devoid of coral reefs
and coral communities. The submerged, leeward bases of
islands and cays represent the principal substrate for the
development of scleractinian corals, but these do not appear
to form a reef framework. Scleractinian development on the
windward sides of the islands is negligible. Patch reefs and
spur and groove systems are usually poorly developed on the
outer bank slope to depths approaching 30m. The best
developed coral communities occur below this depth with the
exception of the southwestern sector where reefs are smothered
in sediment.

The biological structure of the bank lagoon is interpreted
as being controlled largely by wind and periodic storm forces
that result in frequent resuspension and eventual offbank
transport of sediment, especially to the southwest. Cay Sal
is not a drowned bank; it is a submerged platform on which
biological impoverishment appears to be maintained through
disturbance phenomena engendered by an open and poorly
developed rim. These stresses prevent establishment of more
complex coral reefs or coral communities, and promote
domination by fleshy algae and other more tolerant organisms.

tpepartment of Biological Sciences, Florida International
University, Miami, Florida 33199, U.S.A.

(Manuscript received March 1983 - Eds.)

INTRODUCTION

Cay Sal Bank is a shallow, detached carbonate bank
lying roughly 100 km south of the Florida Keys, 54 km north
of Cuba and 50 km west of the Great Bahama Bank (Fig. 1).
It is 105 km by 66 km in its greatest dimensigns, and
constitutes an overall area of nearly 4000 km*. The rim
is lined with a scattering of islands and rocks especially
along the northern and eastern margins. Over 99 percent of
the bank including the southern flank and the entire center
are completely submerged, primarily in depths ranging from
9-16m.

Few studies have been made of this region in spite of
its size and proximity to U.S. coastal waters. Agassiz
(1894) visited the bank, briefly describing some of its
geomorphic features; a description of the bathymetry of the
bank slope (Malloy & Hurley, 1970) and stratigraphic
studies from a well drilled to 5766m by Standard Oil Company
(Myerhoff & Hatten, 1974) have made more recent contributions
to our knowledge of the area. However, descriptions of
the marine communities of Cay Sal Bank have apparently not
been published.

This paper describes the nature and distribution of the
shallow-water communities of Cay Sal Bank by aerial and
satellite photography, coupled with ship-based bottom
truthing by SCUBA observation and dredge sampling. Physical
factors including storm tracks and frequency, wind and wave
data and sediment depths on the bank lagoon are analyzed and
related to community structure.

Materials and Methods

A total of 18 days were spent on Cay Sal Bank, primarily
during the summer months of 1980-1982. Biological observa-
tions were made at 97 stations scattered across the shallow
lagoon and outer margin to a depth of 60 m (Fig. 2). These
consisted of simple visual surveys to confirm composition of
the benthos, hand collections assisted by SCUBA, and 5
minute Capetown dredge tows. Samples of all identified
materials have been deposited in the FIU museum. All species
except as noted were identified by the author.

Sediment depths were recorded at 27 stations (1982 only)
using a steel probe. Where sediments exceeded a depth of
one meter, a 2 1/2 HP water pump was employed to force sea-
water through a 5 meter length of PVC pipe. Sediment
fluidized in this manner enabled the pipe to quickly penetrate
to bedrock.

The names of emergent islands used in this paper
correspond to those given in British Admiralty Chart
No. 1217 (Fig. 2). Coordinate locations have been
modified according to more recent data (see appendix).

RESULTS

a. The Lagoonal Environment

The lagoonal surface of the bank can be divided into
four major biotic zones (Fig. 3). The northwestern sector
with its included sand ridges is characterized by a sparse
but consistent cover of seagrasses and algae including
Halodule wrightii, Caulerpa spp., Syringodium filiforme
and various species of calcareous chlorophytes (Fig. 4A).
Members of this community (hereafter referred to as the
Halodule community) are summarized in Table l. A denser
Halodule community appears to be responsible for several of
the large dark patches noted in satellite imagery of this
zone.

The sediment cover of this quadrant ranges from 2 cm
to lm. The deeper sand accumulations occur behind and
south of Double Headed Shot Cays, (hereafter referred to as
DHS Cays) particularly in association with the intersecting
sets of bedforms prominent in the western part of the zone,
and those trending NE to SW 20 km to the east. The
Halodule zone grades into a sediment-bare, rubble bottom
east of Muertos Cays. This northeastern sector is covered
by a mixed Sargassum-gorgonian-sponge community.

The rubble characteristic of the northeast bank lagoon
continues throughout the southeast sector but without as
much vegetation. The bottom is covered primarily by a
scattering of the brown alga Lobophora variegata, with an
occasional cluster of sponges and gorgonians as above.
Along the southern and eastern borders of this zone the
rubble is interspersed with aggregations of corals, especially
Diploria spp., Agaricia agaricites and Montastrea annularis,
together with sponges and gorgonians (Fig. 4B). For the
most part these do not form patch reefs (i.e., no appreciable
relief above bottom). However, two reef areas are encountered
along the western edge of this zone as noted in figure 3.
One of these near 23°34' and 79°48' consists of numerous
but small (1-2m2) Diploria, Porites and Montastrea patches
rising lm above the bottom (depth = 7-8m). The most
significant patch reef area, several km2 in extent, is
located 10 km southwest of Damas Cays. This subzone was
characterized by thickets of Acropora cervicornis rising to
a depth of 6m from a 10m bottom (Fig. 4C). Scattered
colonies of Montastrea annularis, Agaricia agaricites and
Colpophyllia natans contribute to the framework. It may be
Significant that much of the rubble substrate in this zone

consists of what appears to be recent Acropora cervicornis.
There is little evidence of recolonization.

The last zone consists of a sigmoidally shaped area
extending across the bank from Cay Sal to the Damas Cays.
This area is characterized by patches of Thalassia
testudinum which become somewhat more extensive toward the
southwestern (leeward) side. Turtle grass becomes
particularly well developed in the lee of larger islands on
the bank, especially the Double-Headed Shot Cays and the
Anguilla Cays (Fig. 4E). Farther behind the latter group,
Thalassia grades into a Halodule-calcareous green algae
subzone (Fig. 3).

At the edges of this area Thalassia intermingles with
other communities. This is particularly notable west of
Damas Cays where zonation overlap is extensive (Fig. 3).
The Damas Cays area is also notable for the existence of
several "blue holes" (Capt. Bob Klein, pers. comm.). One
of these located at 23°49'87 and 70°47'28, 2.4 km west of
the islands, was briefly investigated. It measures
approximately 100m across and 100m deep, beginning on the
bank at a depth of 10-13m (surface to bottom = 110-113m).
The surrounding area is a Thalassia-gorgonian-sponge
bottom, grading into colonies of Montastrea cavernosa and
Agaricia agaricites at the edge of the blue hole. The
vertical walls are covered with Lobophora variegata to a
depth of 18m, below which Halimeda goreauil dominates.
Submersible observations at the bottom reveal numerous
Strombus gigas shells apparently the result of the animal
becoming entrapped while migrating through the surrounding
turtle grass (E. Shinn, pers. comm.). A wider and slightly
deeper blue hole is located a few km farther west (Fig. 4F).

The sediment cover of the Thalassia zone is highly
variable. Through most of this region the range is 2-5cm,
increasing to 20-60cm under Thalassia itself. Just north
of Cay Sal Island in an area covered by a mixed community
of scattered angiosperms and calcareous green algae, a
sand body 4-4.5 meters deep was encountered (Fig. 4G). The
area covered by this accumulation was not determined, but
several sediment stations taken around the periphery of
Cay Sal indicates that it is highly localized.

b. The Bank Rim and Slope

The only areas characterized by substantial coral
development are the bank slope below 30m and the submerged
portions of the islands. Most of the larger cays have
been examined and appear to be uniform with regard to their
flora and fauna from the littoral zone to the base of the
island (Table 1). The sublittoral portions are

characterized by an intertidal bench cemented with an
unidentified encrusting coralline alga. Immediately below
this surge zone, dropping vertically to a depth of 7-8 m, is
a coral community consisting of yellow and purple sea fans

(Gorgonia ventalina and G. flabellum) plus a variety of
other gorgonians, corals and hydrocorals, especially Millepora
complanata (Fig. 5A). In general the amount of scleractinian
development is greater along the northern border of islands,
but only along the lagoonal side where Montastrea annularis,
Diploria spp. Siderastrea siderea, Agaricia agaricites and
Porites porites become especially numerous (Table I,

Fig. 5B). However, the coral communities appear to be
insufficiently developed under the best of circumstances to
prevent erosion of the underlying substrate. Large blocks
of island material are usually found adjacent to the cays and
these serve as substratum for additional albeit superficial
coral development (Fig. 5C,D).

Shallow water coral development along the oceanic side
of the islands is not appreciable. Acropora palmata, for
example, is found only in isolated pockets (e.g. between
Water Cays and some of the Damas Cays. There is no "palmata
zone" (cf. Geister, 1977) characteristic of any of the
islands. Along the eastern bank there is little difference
between exposed. and sheltered sides of the islands with
regard to coral development. The same species of coral as
noted above form spurs <lm in height in 10m depth directly
in front of many islands along the Santaren Channel.

However, even this limited amount of coral growth does not
occur on the ocean side of the DHS Cays where the bottom at
10m is composed of rock colonized by Sargassum spp.,
Dictyosphaeria cavernosa and Microdictyon sp., along with
occasional gorgonia and sponges (Fig. 5E). Coral communities
are not developed on either the exposed nor the sheltered
sides of south Anguilla Cay or Cay Sal due to accumulation
of sand.

In depths of 15 to 25m along the eastern bank, spurs
3m high are covered by Acropora cervicornis, Siderastrea
siderea, Montastrea annularis along with large quantities of
gorgonians, Halimeda spp. and Lobophora variegata. South
of south Anguilla Cay (in the Nicholas Channel) spur and
groove development is somewhat greater (Fig. 6A) but similar
in composition and in coral density to those at Dog Rocks.
There appear to be no comparable coral communities in these
depths along the DHS Cays or near Cay Sal.

Outer reef slopes have been investigated briefly on
several sides of the bank in depths ranging from 25-60m. At
25m the angle of slope begins to increase, allowing a
relatively dense algae-sponge-gorgonian community. Some
scleractinian coral development is also in evidence but is

not strongly represented (Fig. 6B). The outer reef
escarpment ("dropoff") begins at 44-46m on the eastern side
of the bank and at 38-40m on the western and northwestern
sides. There is a substantial difference in the structure
of the deep reefs developed on these slopes. Off south
Anguilla, for example, the dominant organisms are Lobophora
variegata and Halimeda spp. interspersed by sponges, some
coral (primarily Montastrea spp.), whip-like gorgonians
(Ellisella and Eunicea spp.) and antipatharians
(Cirrhipathes luetkeni). The diversity of deep reef
Organisms here is relatively low; the face of the escarpment
is smooth, without appreciable development of ledges, caves
and overhangs. The same description applies to the deep
reefs off southern Dog Rocks, however diversity of organisms
and relief in the slope is somewhat greater off the northern
Dog Rocks group.

Scleractinian coral development at depths below 25m is
greatest off the northwestern and western border of the bank,
along the edge of the Straits of Florida. Off Elbow Cay,
for example, an appreciable development of Montastrea spp.
Porites astreoides and Agaricia agaricites begins at 25m
(Fig. 6C). The latter species forms an extensive cover
that continues over the escarpment to depths of at least
50m. The central portion of the western bank margin drops
precipitously into the Straits of Florida. The outer reef
slope here is as well developed as I have seen it in tnis
area. The escarpment beginning at 38m is characterized by
spurs extending seaward more than 10m from the wall. From
the amount of coral cover these appear to be the result of
recent growth although no cores have been taken. Flat,
platey forms of Montastrea spp. and Agaricia lamarcki,
along with large colonies of Colpophyllia natans dominate
these structures along with numerous sponges, gorgonians
and antipatharians (Fig. 6E). In direct contrast, the
outer slope around Cay Sal island has no reef development
at all; off the northern end in particular, the outer
reef slope is totally inundated with sediment (Figs. 6D,7).

DISCUSSION

Unlike the larger Bahamian banks, Cay Sal has a

largely submerged, poorly developed rim. Agassiz (1894) and
Davis (1928) refer to the bank as a drowned atoll emphasizing
the apparent inability of coral growth to keep pace with
subsidence or rise in sea level. The process of drowning may
be initiated by a variety of factors (reviewed by Schlager,
1981) which commonly result in bank or platform surfaces

50m or more below present sea level (Davis, 1928). In such
cases the use of the term "drowning" may be justified because

processes operating in the past have placed reef-
associated organisms out of their effective depth range
for photosynthesis. Cay Sal Bank lagoon, on the other
hand is only 9-16 m deep, submerged, but well within the
range of appreciable carbonate production (Schlager, 1981)
and reef growth (Macintyre, 1967; Porter, 1973; Goreau &
Land, 1974; Rutzler & Macintyre, 1982). As noted above,
reef growth is occurring on at least some of Cay Sal's
deeper margins. Therefore the notion of reef drowning as
means of accounting for this bank's present biotic
composition is untenable.

The antithesis of platform drowning is physical control
by shallow water processes. Shallow water is subject to
a wide variety of environmental alterations inimical to
reef development. These may include exposure and thermal
disturbances (Glynn, 1968; Roberts et al., 1982) chemical
alterations (Newell et al., 1959; Voss & Voss, 1960;
Milliman, 1973) and floods of fresh or turbid water
(Goodbody, 1961; Lighty et al., 1978). Although none of
these processes is likely operative on Cay Sal Bank today,
such stresses may have served to reduce early Holocene reef
growth enough to account for its poorly developed rim. The
lack of a protective rim, in turn, may have promoted
conditions which account for the sparsely colonized, low
diversity, ahermatypic environment typical of the bank
shallows.

Although the mechanisms and trends of the sequential
replacement of communities through time are controversial
(Connell & Slayter, 1977; Sousa, 1980; Greene & Schoener,
1982), the process of succession is generally understood
to culminate in one or more communities called climaxes.
Such communities are widespread in a given climatic regime
and are typically characterized by an equilibrium between
production and respiration, a relatively high diversity of
species, a well-developed spacial structure and a complex
food web (Odum, 1969). In the coral reef environment, the
normal successional process predicts eventual stabilization
of soft bottom communities by Thalassia (Ginsburg &
Lowenstam, 1958; Patriquin, 1975) or coral communities
(Jones, 1977). However, it is generally recognized that
local conditions may often prevent the succession to climax.
In these cases, terms such as edaphic climax, cyclic climax,
disclimax or subclimax have been applied (Odum, 1971).
Species diversity as one of the more readily measurable
ecological parameters, is often employed as a standard by
which the degree of community complexity can be gauged.
High diversity is maintained by some measure of disturbance
Or non-equilibrium conditions that prevents monopolization
of resources by superior competitors (Connell, 1978;
Pearson, 1981; Sheppard, 1982). However, frequent and/or

severe disturbance can return the community to an immature
(early successional) stage or perhaps inhibit succession
entirely. For example Dollar (1982) found that wave and
storm stress caused frequent mass mortalities on an

Hawaiian reef, resulting in a low diversity, relatively
simple coral reef community. Frequently after disturbance
by storms or other stresses, damaged reefs will be colonized
by fleshy algae; their continued dominance is limited by

the time required for recovery of the coral community
(Pearson, 1981 and contained references). Thus algal-
dominated reefs may be viewed as an indication of disturbance
to a degree that does not allow the normal process of
succession or recovery to occur. Lighty (1981) has described
such an environment in the northern Bahamas (which he
unfortunately refers to as a "climax community") and
correlates this condition with high energy stress. A some-
what similar situation is described by Adey et al. (1977)

in the Lesser Antilles. The following evidence suggests
that Cay Sal Bank's low coral diversity (Table 1) and
dominance by fleshy algae as well as other flora, is also

a function of environmental stress.

The lagoon of Cay Sal is dominated by the seagrass
Halodule wrightii and associates. Halodule is an opportunist
species that colonizes areas either unsuitable for Thalassia
Or areas where Thalassia has become disturbed by storms or
other factors (den Hartog, 1977). As a pioneer, Halodule
is a poor competitor and under normal conditions is replaced
by species with more extensive, stabilizing blade and
rhizome systems (Scoffin, 1970; Burrell and Schubel, 1977).
This succession is not evident at Cay Sal where Thalassia is
strongly developed only in the lee of larger islands.

The distribution of sediment on the bank (Fig. 3)
corresponds roughly with the general description given by
Enos (1974). One of the more striking aspects of this
distribution is the amount of bank surface with little or no
sediment. More than half of the lagoon is sediment-bare
especially the eastern side. The sediment cover generally
increases toward the west, and is concentrated largely in
the form of sand waves behind DHS Cays, and in a relatively
deep (>4m) sand body restricted to the north side of Cay Sal
Island. The virtual absence of sediment on the eastern
margin and its accumulation toward the southwest suggests
active transport. Moreover, the smothering of the outer
reef slope coral communities around Cay Sal Island provides
evidence that this transport is offbank, as confirmed
recently by seismic profiles (Hine, personal communication).

Wind and storm generated flows are likely agents of
offbank sediment transport (Hine et al., 1981; Hubbard et al.,

1981). Two categories of storms to consider are acute,

periodic tropical storms occurring in summer and the more
regular, chronic disturbances associated with the passage

of winter frontal systems. A chart depicting the approximate
path of tropical storm and hurricane systems passing within
100 km of Cay Sal Bank is presented in Figure 8. Although
no data are given on storm intensities, 32 cyclonic storms
have been noted since 1871, plus an additional 4 tropical
depressions. Nine storms or hurricanes have crossed the
southeastern bank in the vicinity of the Anguilla Cays,

9 more have crossed (or passed parallel) in an east-west
direction, while another 7 crossed the bank near Cay Sal.
Given the openness of the bank, severe storms and hurricanes
are certain to effect damage, even on deeper reefs (cf.
Woodley, 1980). However, the overall importance of tropical
storms on Cay Sal is difficult to assess. With an average
of 3 storms per decade, Cay Sal is less frequently affected
by such systems than the Florida Keys or Little Bahama

Bank where an average of 7-8 storms per decade occurs
(Neumannisetyall) 1977 ;) Hine, 1977). | During the Last (decade
only one hurricane has passed near this area (1981); more-
over, the pattern of storm crossings does not correspond
with either the degree of community development or the
pattern of observed sediment accumulation.

The small amount of hydrographic/meteorological informa-

tion available for the area is summarized in Figure 9. Winds
are principally from the east during most of the year but
display a prominent shift to the north and northeast during
the winter. This change corresponds with the increase in
percent of sea and swell near the bank. The passage of
frontal systems from the north and northeast is a reliable
and persistent winter phenomenon in this region (U.S. Naval
Weather Service Command, 1975) and may account for the
following observations.

1) Acropora cervicornis rubble is common in the south-
eastern sector of the bank while living colonies are relative-
ly uncommon. Storm forces may provide rubble substratum
through recurrent cycles of Acropora growth and recovery
(Gilmore & Hall, 1976; Tunnicliffe, 1981) followed by storm
destruction. The dominance of an unstable rubble substrate
in turn reduces the chance of coral survival and recoloni-
zation (Goreau, 1959; Stoddart, 1974; Pearson, 1981).

2) The best developed shallow coral communities are
on the protected lagoon side of the northern cays; the
poorest development is on the unprotected ocean side. The
reason for this contrast may be the abrupt transition between
shallow and deep water that allows large waves to pound the
outside of these cays. For example, a 50 km hr-1 wind from
the north or northeast will produce waves at least 3.2 m
high (U.S. Army CERC, 1973). Such wind/wave conditions are
probably common near Cay Sal (see below).

3) A Thalassia zone first noted in 8m depth behind
northern Dog Rocks during July, 1981, was replaced by rubble
twelve months later. Aerial photographs taken during May,
1982 revealed crescentic "blowout" structures in Thalassia
beds behind Water Cays in 8-9m depth (Figs. 6D,E), and north
of Cay Sal in similar depths (Fig. 4C). These are known to
result from storm damage and indicate the direction of energy
propagation (Patriquin, 1975). The blowouts on Cay Sal Bank
are concave from the north.

Storm-induced bottom currents and wave activity, are
capable of considerable sediment resuspension and transport
(Hine et al., 1981; Murray et al., 1977) known to be
detrimental to coral development (Dodge et al., 1974; Loya,
1976). The amount of transport can be estimated using
established relationships (Figs. 3-15, 3-29, 4-20 and 4-21
in U.S. Army CERC, 1977) between wind stress and maximum
induced motion on the sea floor (Umax(-d).

Northeast and easterly winds near Cay Sal reach speeds
of 50 km hr-l, 20-25% of the time during October-April.
Winds during the other months approach this speed only 6-12%
of the time (U.S. Naval Weather Service Command, 1975).
Winds of 50 km hr7! from the east in llm water depth
(average lagoon depth) will generate waves 1.4m high, with
periods of 4.7 sec and will produce Umax(-d) of 25 cm sec™ -1
on the lagoon floor. This is within the generally accepted
range of 15 — 30 cm sec7l required for fine to moderate
sized sand grain motion (U.S. Army CERC, 1977; see also
G@iscussion in Hine et al., 1981). The principal limitatvon
to bottom current generation with easterly winds on Cay Sal
is the limited fetch (65 km). However, with winds from the
northeast, fetch increases 2 1/2 fold. Thus a 50 km hr7
wind will produce waves 1.6 m high, with periods of 5.2 sec
and will produce Umax(-d) of 47 cm sec-l. This figure is
well above critical velocity and may account for accumulation
of sediment toward the southwest, as well as disturbance to
the lagoon and SW bank slope communities.

Thus the physical environment of Cay Sal Bank appears
to be sufficiently vigorous to produce direct wave stress as
well as current-induced sediment stress. These conditions,
while by no means unique, combine with the historically
derived lack of a protective rim to produce high energy
channels into the bank interior. The result is the mainte-
nance of a virtually reefless environment.

ddl

Table 1. Marine plants and invertebrates characteristic of

Cay Sal Bank Lagoon. Zones:

Halodule,

2 = Thalassia, 3 = Rubble-Lobophora, 4 = Sargassum-
gorgonian-sponge, 5 = Island-littoral

Angiosperms

Halodule wrightii Ascherson
Thalassia testudinum Koenig
Syringodium filiforme Kutzing

Algae

Avrainvillea nigricans Decaisne
Caulerpa prolifera Lamoroux
Caulerpa cupressoides Agardh
Cladophora sp.

Dasycladus vermicularis Krasser
Dictyopteris justii Lamoroux

Dictyosphaeria cavernosa Boergesen

Dictyota dentata Lamoroux
Galaxaura squalida Kjellman
Halimeda incrassata Lamoroux
Halimeda lacrimosa Howe
Halimeda opuntia (Lamoroux)
Laurencia papillosa (Forsskal)
Lobophora variegata Womersley
Microdictyon sp.

Padina sanctae-crucis Boergesen
Penicillus capitatus Lamarck
Penicillus dumetosus (Lamoroux)
Penicillus pyriformis Gepp
Rhipocephalus phoenix Kutzing
Sargassum cymosum Agardh
Sargassum hystrix Agardh
Sargassum polyceratium Taylor
Sargassum vulgare Agardh
Stypopodium zonale Papenfuss
Turbinaria turbinata Kuntze
Udotea spinulosa Howe

Sponges

Anthosigmella varians var. incrustans
Spheciospongia vesparium (Lamarck)

Gorgonians

Eunicea spp.

Gorgonia flabellum Linn.
Gorgonia ventalina Linn.
Muricea muricata (Pallas)
Muriceopsis flavida (Lamarck)

(D&M)

Plexaura flexuosa Lamoroux

Plexaura homomalla (Esper)
Plexaurella spp.

Pseudopterogorgia americana (Gmelin)
Pterogorgia anceps (Pallas)

Scleractinians

Acropora cervicornis (Lamarck)
Agaricia agaricites (Linn.)
Diploria labyrinthiformis (Linn.)
Diploria strigosa (Dana)
Montastrea annularis (E&S)
Porites astreoides Lamarck
Porites porites Lamarck
Siderastrea siderea (E&S)

Molluscs

Acanthopleura granulata Gmelin
Acmea antillarum Sowerby
Antigonia listeri Gray

Chione paphia Linn.

Chiton squamosus Linn.
Echininus nodulosus Pfeiffer
Glycymeris undata Gmelin
Laevicardium laevigatum (Linn.)
Littorina zic-zac Gmelin
Livona pica Gray

Nerita peloronta Linn.

Nerita versicolor Gmelin
Purpura patula Linn.

Strombus costatus Gmelin
Strombus gigas Linn.

Tais rustica Lamarck

Tectarius muricatus Linn.

Arthropods

Grapsus grapsus (Linn.)
Metapenaeopsis cf. goodei (Smith)
Portunus bahamensis Rathbun
Portunus ordwayi (Stimpson)
Portunus spinimanus Latreille
Tetraclita sp.

Echinoderms

Astichopus multifidus (Sluiter)
Astropecten duplicatus Gray
Oreaster reticulatus (Linn.)

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ACKNOWLEDGMENTS

This study was made possible through shiptime grants
supported by the Florida Institute for Oceanography. I am
grateful to Captain R. Millender, Jr., the crew of R/V
Bellows and the staff of FIO for their cooperation and
assistance in making a success of these cruises. I thank
the Government of the Bahamas, Ministry of Fisheries for
their cooperation and courtesy in granting permission to
conduct research in Bahamian waters. Funding for aerial
photography was provided by a grant to the author from
Florida International University. I thank Keith Wylde for
his expert piloting; M. McLean and M. Upright took the
aerial photographs. P. McLaughlin and R. Lemaitre identified
the crustaceans and A. Labonte provided the equipment used
in sediment depth determinations. I thank my colleague
J.C. Makemson for drafting the pen and ink drawings and
labels accompanying the figures in this paper, and
Capt. Bob Klein for providing the aerial photograph of the
Damas Cay bluehole (Fig. 4F). Finally I thank A.E. Hine for
comments that considerably improved the manuscript.

FIGURE LEGENDS

Figure 1. Geographic position of Cay Sal Bank from ERTS/
LANDSAT imagery. Scale bar = 10 km.

Figure 2. British Admiraly Map No. 1217 (Rev. 1977). Inset:
Station positions on Cay Sal Bank.

Figure 3. ERTS/LANDSAT composite depicting the biological
zones and subzones of Cay Sal Bank. Encircled
numbers indicate thickness of sediment in cm.
Sand waves in northwest lagoon are covered with
Halodule as are NE-SW oriented sand waves to the
east. Dark region between these structures is
result of denser accumulations of Halodule and
calcareous green algae. Note sand accumulation
near Cay Sal on the southwest corner. Double
Headed Shot Cays, Dog Rocks, Damas Cays and
Anguilla Cays are also visible along the bank
margin.

Figure 4. Communities of Cay Sal Bank Lagoon:
(A) Halodule-Caulerpa-calcareous green algae
community typical of the central lagoon. Note
numerous volcano-like burrows, possibly of
callianassid shrimp; Sea star Oreaster reticulatus
lies next to scale bar, = 60cm; depth = 13m at
23°50'N and 80°20'W 13 km SE of Elbow Cay.
(B) Rubble dominated bottom along southeast bank
is occasionally colonized by coral clusters
composed of gorgonians, especially Pseudopterogorgia
spp., and scleractinians Montastrea annularis,
Agaricia agaricites and Porites porites (vertical
view, Depth: 13m).
(C) Acropora patch reef southwest of Damas Cays
in 7-8m depth at 23°34'N and 79°48'W.
(D) Aerial view of Thalassia development, eastern
Water Cay; scale bar = 5m. Note crescentic
blowouts indicating bankward storm direction from
the north.
(E) Underwater detail of above; crescent is 10m
in diameter; depth = 8-9m.
(F) Blue hole 5-6km west of Damas Cays; note coral
patches developed on edge under boat; scale bar =
100m.
(G) Sand body 4.0-4.5m deep in 8m of water, 2km
north of Cay Sal. Divers are measuring sand depth
by inserting 5m length of PVC pipe. Note oriented
megaripples indicating sand motion, and sparse
colonization of sediment by Halodule and calcareous
green algae.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

Communities of the Bank Rim:

(A) Intertidal bench with typical wave resistant
Gorgonia spp. from lagoon side of Bellows Cay
(see appendix map).

(B) Coral development below the surge zone with
extensive cover of Agaricia agaricites and large
(=1m3) colony of Montastrea annularis: lagoon
side Crenula Cay, 0-6m (see appendix map). Scale
bar = 60cm.

(D) Colonization of above by Millepora complanata
and small colonies of Diploria strigosa and
Montastrea annularis; scale bar = 60 cm.

(E) Ocean side Elbow Cay showing lack of coral
development on island base. Note spur and groove-
like system and scour holes; scale bar = 60 cm,
depth = 3-10m.

Communities of the Outer Reef Slope:

(A) Deep spur systems in Nicholas Channel south

of Anguilla Cays, 23°22'N and 79°34'W. Note
profusion of gorgonians and sponges. Scleractinian
development is occasionally moderate but generally
poor. Spur height = 3-4m; Depth = 20-25m.

(B) Edge of escarpment at above location. Note
gorgonians and sponges but poor scleractinian
development; Depth = 35m.

(C) Development of Agaricia agaricites and porites
astreoides on the edge of the escarpment off Elbow
Cay; flabellate gorgonian is Iciligoria schrammi.
Depth = 30m.

(D) Escarpment off north Cay Salplanketed in fine
sediment of undetermined thickness. Coral at
center is mud-dwelling sclearactinian, Meandrina
danae = 12 cm long. Note conch trails (Strombus
gigas) above; Depth = 30m.

(E) Deep spurs on the escarpment north of Rompidas
Ledge composed largely of platey growths of
Montastrea annularis.

Comparison of fathometer profiles from Cay Sal
Island northward at 15 to 30m depth. Arrow
indicates increased inflection of outer reef

slope at 20m. Distances north of Cay Sal:

1 = 3km, 2 = 4km, 3 = 5.5km, 4 = 6.5km, 5 = 8km.
Note smooth surfaces indicative of sediment

drowning near Cay Sal and increased reef development
toward Rompidas.

Tropical storm and hurricane track passing within
100 km of Cay Sal Bank, 1871 through 1981. Year

Figure 9.

of each track indicates direction of continued
motion. Data from Neumann et al. (1978) with

additions from NOAA Mariner's Weather Log
(1977-1982).

Climatic and hydrographic conditions near Cay Sal
Bank. Data compiled from West Indies Pilot
(1957), Wiist (1964), NOAA (1973) and U.S. Naval
Weather Service Command (1975).

Aualonpe ;

—.

—
=

rure

0-5 km

Figure 7

——— hurricane
- — — tropical storm
@*0 ee tropical depression

FLORIDA

1952

1933a
\

is % > ° : ) |
1928 a : 7 Uf. Se 1926
x [7 <] A ° .

Figure 8

% Sea and Swell Conditions >2m

May 18 8 4,448 i _ MARCH

August 15 6 6,417 *'L| FREQUENCY

November 25 I5 S55
February 20 l2 4,667

oer”
aM 26| | %WIND
BOs FREQUENCY
pr” eee =52,995
Ker
S* 6
oo cas\

°? ss
& ANNUAL SURFACE o &
SALINITY ABs
36:00-3632%0 N=50 a, “t
TEMPERATURE \ Og ES
24-4 - 28-9°C cy Y

Figure 9

18
APPENDIX

The lack of basic information on Cay Sal Bank is
perhaps no better reflected than by considerable errors in
its charted position (British Admiraly 1217; Defense
Mapping Agency 11451; NOAA 11013). The purpose of this note
is to correct mapping errors by employing aerial and
satellite photography coupled with ship-based navigational
techniques and bottom soundings. Additional information is
presented on the biotic composition and morphology of major
islands.

Data on the bank were obtained during three cruises
of the R/V Bellows in the summers of 1980 through 1982.
Position fixing aboard the vessel employed by simultaneous
use of a 7100 Micromarine LORAN C Navigator computer, plus
a Micrologic ML-320 LORAN-C Navigator as a backup. An ITT
Decca Marine 801 satellite navigation computer and a Decca
RM 914 radar unit (77 km range) were used to confirm LORAN
data. Bathymetry information was obtained using a
Raytheon Explorer III recording fathometer (to 75 fathoms)
and a Raytheon DE-731 recording fathometer to (410 fathoms).

All islands and rocks were surveyed by oblique aerial
photography from an altitude of 600 meters. These were
supplemented by aerial photographs of the Anguilla Cays
made available by the U.S. Defense Intelligence Agency.
The low altitude photographs were employed in conjunction
with ERTS/LANDSAT imagery and shipboard position fixing in
the construction of a map of the bank, accurate to within
+ 300 meters.

Results of the mapping of Cay Sal Bank are depicted in
Figure 1. Comparison with the 1890 British Admirality
Chart (Fig. 2) shows an error between 1 and 5 km in the
position of the islands, the magnitude of which is greatest
in the southeastern portion of the bank. The shape of
larger islands has been more accurately depicted and some
have been named (Crenula Cay, North and South Dangerous
Rocks and Bellows Cay). The bathymetry of the bank as
Originally presented appears to be essentially correct for
the relative position of the 5 fathom curve. Only minor
corrections have been inserted. The position of the
25 fathom (=100 F) curve has been fitted using satellite
imagery (text fig. 3).

Some of the shoal water areas depicted on the British
chart (and copied on all other charts) could not be located
despite numerous attempts. Most notably, areas such as
Lavanderas Rocks, east of Cay Sal and "Dangerous Shoal"
depicted on the central eastern border (Fig. 2) are no

shallower than 3.5 to 4 fathoms. This is also true for the
shoal areas near the center of the bank. Repeated
crossings have indicated that the lagoon is generally no
shallower than 3.5 fathoms (6.4m) at MSL. The exception to
this rule is a small (vlkm2) area on the western bank
referred to as Rompidas Ledge, where the bottom shoals to
less than two fathoms, and large scattered heads of
Montastrea annularis project close to the surface.
Navigational maps place Rompidas over 5km from its actual
position. However, the site is now marked by a cargo ship,
M/V Cork that ran aground on Rompidas in 1983. The
location of this submerged shoal can now be seen clearly
from a distance of over 15km.

APPENDIX
FIGURE LEGENDS

Figure 1. Chart of Cay Sal Bank with revised coordinates
according to LORAN and radar positioning; twenty-
five fathom (=100F) curve fitted from satellite
imagery.

Figure 2. Comparison of new chart (solid lines) with
British Admirality Chart No. 1217 (dashed lines)
showing 25 fathom curve and position of major
islands. When the 24° and 80° coordinates of
the two maps are overlapped errors of up to 5km
are shown along the southeastern sector of the
bank. U.S. Defense Mapping Agency No. 11461 is
virtually identical with the British map.

Figure 3. Islands of Cay Sal Bank.
(A) U.S. Air Force photograph of south Anguilla
Cay; scale bar = 500m. Note embayed margins
and sand shoals. Salinity of saline lake in
June, 1982 was 37.6Y,, byconductivity. Lake
Margins are covered with cyanobacterial mats
(Oscillatoria sp.) along with those of an
unidentified red photosynthetic bacterium. A
Similar lake on north Anguilla Cay retained a
Sallaniity 70 1451775 )ci
(B) Surface of south Anguilla Cay from eastward
facing dune crest looking north: Development of
palms (Coccothrinax argentata Brown) and scrub
vegetation. Eastern dune face is steeply sloping
and eroded. Poorly cemented eolian sand grains
are typical of the windward side.
(C) Lagoon (western) side of south Anguilla Cay:
bedded structure of well-cemented eolianite cliffs.
(D) Cay Sal from 600m looking toward southern
Florida Straits. Unpaved airstrip at northern
tip of island ends at edge of hypersaline lagoon.
Highest portion of island is 10m ridge at the
eastern tip (lower left). Note sandy shoals
around island and weakly developed blowout
structures at lower right corner. Scale bar =
150m.
(E) Elbow Cay is typical of most islands on Cay
Sal Bank, consisting of karstified eolianite and
coral rubble colonized by maritime vegetation,
primarily Sesuvium portulacastrum Linn. and
Tournefortia gnaphalodes Brown. See Wilson (1909)
and Gillis (1976) for additional notes on Cay
Sal Bank terrestrial flora. This and other rocky
islands of the bank serve as nesting sites for
enormous numbers of sooty and brown noddy terns
during the summer months. See Buden and Schwartz
(1968) for a review of herpeto- and avifauna of
Cay Sal.

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Appendix Fig. 3

ATOLL RESEARCH BULLETIN
No. 272

HENDERSON ISLAND CSOUTHEASTERN POLYNESIA): SUMMARY OF
CURRENT KNOWLEDGE

F. R- FOSBERG, M--H-SACHET AND D- R- STODDART

ISSUED BY

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Fig. 2. Henderson Island (from the Admiralty chart).

HENDERSON ISLAND (SOUTHEASTERN POLYNESIA):
SUMMARY OF CURRENT KNOWLEDGE

by F. R. Fosberg*, M.-H. Sachet* and D, R, Stoddart**

INTRODUCTION

The tropical seas are liberally sprinkled with coral islands.
Many of them are associated with continents and large continental
islands, in relatively shallow water, rising from continental shelves.
Many, also, are in deep water - atolls, barrier reef islets round
high islands, 'almost atolls', tops of drowned karsts, and a few
moderately elevated atolls. These last are among the most fascinating
of all, scientifically.

There is no obvious reason to think that these are anything but
ordinary atolls that have been tectonically elevated a few tens of
metres above present sea level. Yet several features are frequently
observed that are not evident on the sea-level atolls which are pres-
ent in the coral seas in such large numbers. Terra rossa soils cover
the limestone tops of some of them. Phosphate, earthy or indurated,
or both, covers the tops and fills pits and crevasses of some, oc-
casionally in enormous quantities, and is present at least in some
quantities on most or all of them. Fantastically eroded, deeply and
sharply pinnacled and pitted limestone surfaces are common. Endemic
species of plants and animals, very rare on low atolls, are found in
some numbers on almost all raised atolls of which we have even meagre
knowledge. Whether or not these phenomena are related is at present
not clear. Much further work on as many as possible of these islands
is needed to elucidate this problem.

The basic difficulty of the above statement is that, of the 20
or 30 such ‘oceanic’ islands or groups of islands, most have been
greatly altered by long-established human occupancy, or phosphate min-
ing, or both. Of the exceptions, the "Rock Islands' of Palau and the
Lau Group of Fiji are rugged karst, not comparable with raised atolls;
Medinilla has been used as a bombing target; only Aldabra and Henderson
remain reasonably unaltered. We are not here considering the many
"continental’ limestone islands.

* Botany Department, Smithsonian Institution
**Geography Department, Cambridge University

Aldabra and Henderson are topographically and physiographically
very different, though both are probably raised atolls. Aldabra has
been studied intensively during the past 17 years, is now well-known,
and is legally protected. Henderson is relatively poorly known, and
protected only by its remoteness and unsuitability for human habitation.

During the past year the isolation and pristine condition of
Henderson have been and are seriously threatened by a project of a
wealthy American to build a house, landing facilities, and an airstrip
on it. This is being opposed by scientific and conservation bodies,
which are petitioning the British Government to deny permission to
carry out this project. This circumstance has brought out and under-
scored the paucity of reliable scientific information, except of a
reconnaissance nature, about Henderson. This has caused the ARB
editors to bring together a summary of what is known of the geography,
history, ecology, flora and fauna of this island, with a bibliography
of pertinent literature. This paper is, therefore, a factual record
of the published information on Henderson: it sets down what has been
discovered, at what time, and by whom, about the island.

GEOGRAPHY

Henderson is an elevated limestone island situated in 24°22'S
and 128°20'W. Its nearest neighbours are Pitcairn, 200 km to the west-
southwest; Oeno, 200 km to the west; and Ducie, 360 km to the east. It
rises as an isolated conical mound from depths of ca 3.5 km, on a trend
line which continues that of the Tuamotus and Gambiers eastward to
Ducie, and is presumably a reef-capped volcano.

The island has a greatest length of 9.6 km and greatest width of
5.1 km, based on the Admiralty chart; its area is 37 sq km. It is
usually said to rise about 33 m (100 ft) above sea level. Early authors
stressed the flatness of its summit, but those on the Mangarevan Expe-
dition were impressed by a central depression which they interpreted
as a former atoll-lagoon. The upper surface consists of an intricate
dissected limestone, with pits and crevasses 3-7 m deep. The island is
surrounded by steep cliffs of bare limestone, with occasional pocket
beaches. There is a fringing reef 200 m wide, at least on the north
and northwest sides backed by a wide beach (St John and Philipson (1962)).

No meteorological records are available, but the island lies in
the Southeast Trades, and from its location probably has a mean annual
rainfall of 1500 mm. The tidal range at springs is probably close to
that of the Gambiers and eastern Tuamotus (1.0 m) (Admiralty Tide Tables
1983). Tidal measurements at Ducie by Rehder and Randall (1975) showed
a regular semidiurnal tide.

The top of the island, as well as any land at the bases of the
cliffs, is densely vegetated by tangled scrub and scrub-forest, but the
central part of the depression and the makatea are more sparsely covered.
In places, where the forest is taller and the canopy more complete, it
is possible to walk freely for short distances. The tallest trees are

Pandanus tectorius Parkinson, which in places rises as an emergent
above the general canopy. The crowns of such emergents are conspicu-
ously pyramidal or conical. The dried fallen leaves of Pandanus cover
the ground in many places.

The scrub and much of the scrub-forest is in many areas so dense
and tangled that walking through it is impossible without the constant
and vigorous use of a machete, and exhausting and slow even with the
use of one. Such scrub is as likely to be on dissected limestone as
on solid soil, adding to the difficulty of traversing it. In some parts
the difficulty is increased by the presence of Caesalpinia bonduc, a
tangled vine beset with hooked prickles, which amply explain and justify
a mame used in Hawaii for this widely-distributed species, '‘wait-a-bit'.

Fresh water is almost completely absent. Slight dripping has been
observed from the roofs of certain caves. A spring from a rock cleft
below high tide level at the north end of the island has been reported
(Naval Intelligence Division 1943, 92), but its degree of permanence is
unknown. Presumably there is some development of a Ghyben-Herzberg lens
within the island, but nothing is known of this.

Biogeographically the island is very interesting because of its
remoteness from obvious source areas. Comparison of its habitats with
those of sea level and slightly-elevated atolls in the Tuamotus, in
terms of effective salinity, proportions of different substrata (sand,
dissected limestone, cliffs, level soil, etc.) is of great potential
interest, but has yet to be considered except in a very preliminary
Manner. Study of the effects of geologically long continuous exposure
above water, compared with the very short history of emergence of the
sea-level atolls, could be rewarding. None of these lines of research
can develop very far without much more information about the island
than we have at present. Comparison with Aldabra would then be profit-
able.

ARCHAEOLOGY

As noted above, Henderson has been, in historic times, uninhabited,
with only brief visits by Pitcairn Islanders and occasional scientific
parties. However, on one such visit, in 1971, Dr Yosi Sinoto, of the
Bishop Museum, discovered and made preliminary investigations on an
archaeological site at the north end of the island. With his kind per-
mission we quote his preliminary account of this discovery from a paper
read in Nice in 1976:

"Henderson Island, known also as Elizabeth Island, is located
about 105 miles northeast of Pitcairn Island. This tiny, raised, coral-
limestone island is flat-topped with 100-ft-high cliffs rising from the
shorelines. Since some time before its discovery by Quirds in 1606,
the island has been uninhabited (Markham 1904). In 1971, while pros-
pecting on the north shore, we found five shelters, one of which in-
cluded burials, and a cave. The cave is situated at the base of a
cliff at the back of the beach flat. Test pits in front of the cave

revealed three cultural layers. The top of Layer II was a hard, coral-
pebble-paved layer indicating an occupational floor. At the bottom of
Layer III we found a fireplace on top of the sterile deposit.

"More than 250 portable artifacts were uncovered from the excava-
tions. These included 100 fishhooks and blanks, of which 75 are pearl-
shell, and 90 coral (Porites sp.) abraders for making fishhooks. There
were 36 basalt adz sections and fragments. This is striking because
basalt rocks and pearl shells are not available from the island, and
the distribution of these artifacts in the three cultural layers is
revealing. The lowest layer yielded only pearl-shell fishhooks,
Hawaiian-Marquesan-type coral files, and basalt adzes, all broken be-
yond type identification, except that cross sections could be recognized
as quadrangular to trapezoidal. The quantity of these artifacts de-
creased in the middle layer and was drastically reduced in the top layer,
where hammer-oyster-shell hooks and Henderson-type coral files appeared.
In the top layer, fossilized Tridacna-shell adzes appeared. Gradual
material adaptation - the gradual change from the use of imported ma-
terials to the use of local resources - is excellently demonstrated
here. Pearl-shell fishhook types found were early Marquesan, Phase II,
and coral files were Hawaiian-Marquesan types, previously found only in
those two island groups. There is no doubt that the early Henderson
material culture had a close affiliation with the early Marquesan cul-
ture; as the materials that were brought to Henderson were exhausted,
the locally available resources were exploited. There were eight
pieces of volcanic glass, resembling pitchstone fragments, associated
with basalt adzes and pearl shells. These are also foreign to the
island but may suggest contact with Pitcairn Island, where pitchstone
is available. Another shelter yielded artifacts made only of local
materials.

"A charcoal sample collected at the bottom of the cave site was
dated at A.D. 1160+110 (1-6344) and charcoal from the top of the middle
layer was dated at A.D. 1455+105 (1-6343). Thus the span of the occu-
pation at this site was more than 300 years. Quirds's party landed on
Henderson in 1606 and found pandanus trees, but no inhabitants. What-
ever the reason for the disappearance of the inhabitants, it must have
happened just prior to Quirds's visit."

DISCOVERY

The island is named after Captain James Henderson, of the Hercules,
who called there on 17 January 1819: Beechey (1831, I, 64) proposed
that Henderson's name be applied to it, rather than that of the vessel
Elizabeth, then used on charts, on the grounds that the Hercules visit
preceded that of the Elizabeth by several months. Beechey also er-
roneously suggested that both ships had been preceded by the crew of
the wrecked whaler Essex. In fact Hercules was first, followed by
Elizabeth, Captain Henry King, on 1 March 1819, and members of the
crew of the Essex from 20 December 1819 until 5 April 1820. Beechey's
vessel H.M.S. Blossom called on 3 December 1825, and was responsible
for the first scientific observations.

Beechey's account of the discovery of Henderson has been followed
by several later authors, including the Admiralty Handbook (Naval In-
telligence Division 1943, 92) and St John and Philipson 1962, 176).

As early as 1837, however, Moerenhout suggested that Henderson was
among the islands discovered by Pedro Fernandez de Quirés in 1606, a
proposal adopted by Meinicke (1876), Beltran y Rézpide (1882-3),
Caillet (1884), Markham (1904) and Sharpe (1960). Maude (1968, 66)
commented that "there can be no doubt as to the identification of these
islands’.

Accounts of the Quirés expedition

Quirés sailed from Callao, Peru, on 21 December 1605, in his flag-
ship San Pedro y San Pablo, together with the Almiranta and San Pedro.
He gives the following account in his Narrative, edited by Markham
(1904) :

"On the 25th [ January 1606] we saw the first weeds; and
on the 26th we saw birds of several kinds flying together.
On this day, at 11 o'clock, we discovered the first island
in latitude 25°, and reckoned it to be 800 leagues [ca
4740 km ] from Lima. It has a circumference of 5 leagues
[30 km], many trees, and a beach of sand! (Markham, ed.
1904, I, 192).

This island, subsequently identified as Ducie Atoll, was variously
termed Luna-Puesta and La Encarnacién. Quirds stood off to westward
without landing.

"Still steering on the same course, on the 29th of January,

at dawn, we sighted another island near, and presently stood
towards it. The launch to the S.W. found a port in a small
bay, where she anchored in 27 fathoms, and almost on shore.
The ships did the same. ... Three men were sent from the
Almiranta in a dingey to land. Fearing to remain they came
back quickly, bringing certain fruits known to some on board,
which were too unripe to eat. They said that the landing was
very bad for a dingey, and would be much worse for larger
boats. This island was supposed to be 870 leagues [ 5160 km ]
from Lima. It is 10 leagues [ 60 km] round. It is massive,
moderately high, open, having groves and plains. It is steep,
too, and its beaches are rocky. It is only inhabited by birds.
Its latitude is 24°45'. It was named 'San Juan Bautista’; and
as it had no port where we could get wood and water, we con-
tinued our voyage to the W.N.W." (Markham, ed. 1904, I, 193).

San Juan Bautista is the island identified as the present Henderson.

The discovery of the two islands is also described by the Chief
Pilot, Gaspar de Leza. The first, Ducie, which he called Anegada, was
met with on 26 January 1606 in latitude 25°S, 1000 leagues [ 5900 km]
from Callao. During the 27th they sailed on, and at 10 leagues [ 60 km]

NW by N determined their latitude as 24°50'S. On the 28th they made
30 leagues [ 180 km ] ona westerly course. 'This day we again saw a
great number of birds of many kinds, chiefly grey gulls and terns.'
The discovery of Henderson is described as follows:

"29th. Second Island: Sin Puerto. - 24°45'S., 1075 leagues
6375 km J from Callao. In the morning we saw another island,
about 6 to 7 leagues [ 35-42 km ] long, N. and S., all flat,
with a hill to the S. It is all clean rock round the coast.
The distance from the 'Anegada' is about 75 leagues [ 445
km ]. ... This island is very green, and full of trees and
open spaces. The wind which blew over this island brought a
smell of flowers and herbs: for they were abundant. The
Almiranta got out a skiff, and sent it to the shore with three
persons. They jumped on shore, but were afraid to leave the
boat. They brought back certain fruits and herbs, and said
that they saw pebbles of different colours on the beach, and
stones which they did not know, but which were pleasant to the
sight. ... To the NE. of the place where we had been there
was a beach, which appeared to be larger than the first; and
if any one should chance upon this island at any time, the N.E.
side should be taken to find this beach." (Markham, ed. 1904,
II, 330-331).

Yet a further name for Henderson is provided by the second-in-
command, Luis Vaez de Torres, when he states that the second island
discovered was ‘about 10 leagues [ 60 km ] in circumference. We named
it San Valerio’ (Markham, ed. 1904, II, 465). Juan de Iturbe on the
same voyage describes Henderson as ‘seventy leagues [ 415 km ] distant
from the first, completely round and uniform of aspect with sheer
cliffs. It would be seven leagues [ 42 km ] in circumference' (Kelly,
ed: 1966, Tk; 281).

Finally, Fray Martin de Munilla, chaplain to the fleet, gives a
more circumstantial account:

"an island, a little over ten leagues [ in circumference ]
[ 60 km ] was sighted rising from the sea about eight varas
6.7 m; 1 vara = 84 cm ]. It was flat and round, the higher
parts bore a uniform aspect, but formed after the manner of
riven rock with some high cliffs facing the sea. ... We saw
a small beach between two morros [ bluffs Ae ... Two men went
ashore and brought back a fruit like a green pineapple [Pan-
danus ]. Two Chinese who were on board the capitana said that
the fruit was edible and that it was plentiful in China. Re-
turning presently they reported that the harbour was not suit-
able, but that there were fish in abundance. There, too, they
found some trees, though these were small, but they had seen
no sign of people. ... This island would be sixty leagues from
the other [ 355 km from Ducie ] and in relation to each other
they stood EW 1/4 NWSE. It lies in latitude 24-3/4°S ."
(Kelly, ed. 1966, I, 153-155).

Account of Captain King

After the Quirds expedition there are no further recorded visits
to Henderson until that of the Hercules on 17 January 1819: we have
seen no account of that occasion. However, King (1820) has described
his visit with the Elizabeth on 1 March 1819. He found

"a large island on the weather-beam, .... as level as a bowling-
green. ... [ we ] endeavour to land at a sandy-beach not far
distant from the ship, which, after some difficulty, we accom-
plished. After hauling the boats up among the trees, we all
went up in different directions; within hail of each other, in
quest of vegetables or animals; but, after a search of four and
a half hours, we returned to the boats, having seen one parrot,
and shot a few pigeons. The island abounded with young trees
and underwood, nor did we observe the smallest appearance of
quadrupeds, except here and there a rat; the ship's name
Elizabeth, was now given to the island. The British Colours
were displayed on the island, and greeted with three cheers,
and a bumper of grog was drank to the health of his Majesty.
While these ceremonies were performing, a proper person was em-
ployed in carving the ship's name, and the other particulars
upon a tree, near the spot we landed. ... We landed on the
south-west part of the island, among some coral rocks, at the
back of which is the beach before mentioned. It appears about
six leagues in circumference, and we found no anchorage. C
The latitude of Elizabeth's Island is 24°26'S., longitude west
of Greenwich 127°50'." (King 1820, 381-382).

The wreck of the Essex

The destruction of the whaler Essex, Captain George Pollard, by a
whale on 20 November 1819 on 0°40'S., 119°O'W, and the subsequent voy-
age in small boats of the survivors to Henderson and beyond provided
the origin of the Moby Dick story made famous by Melville. The boats
arrived at Henderson on 20 December, after drifting for a straight-line
distance of 2100 km. Most of the party left again for the Juan Fernan-
dez Islands after a few days at Henderson. Their boats became separated
and the survivors suffered appalling privations: in the captain's boat
the cabin boy, Owen Coffin, was selected by lot to be killed and eaten
after the food was finished, and another man who died was also cannihale
ised. The first mate's boat was finally rescued in 33°45'S, 81°03'W,
close to their destination, after a voyage of some 4000 km. The three
crew members who had remained on Henderson were finally taken off on 5
April 1820.

Chase (1821; Gibbings, ed. 1935) wrongly identified their first
landfall as Ducie, but it was clearly Henderson: first, because of
their description of the island, and second, because they found there
a tree carved with the words 'The Elizabeth' (Gibbings, ed. 1935, 60)
which had been there ten months before.

The island was described by Chase as "about six miles long and
three broad; with a very high ragged shore, and surrounded by rocks;
the sides of the mountains were bare, but on the tops it looked fresh
and green with vegetation" (Gibbings, ed. 1935, 52). Chappel described
it as "about eight or nine miles round, low and flat, nearly covered
with trees and underwood" (ibid, 78). Of particular interest is Chase's
record of a "fine white beach" in the northwest (ibid, 70).

The Essex narrative is retold by Heffernan (1981), and mention is
made below of other observations made on the island.

Account of Captain Beechey's visit

The most graphic and detailed accounts of Henderson in the early
literature are those resulting from the hydrographic survey made by
H.M.S. Blossom under Captain F. W. Beechey during a single day in
December 1825. Beechey's own account is as follows:

"At noon on the 2d of December, flocks of gulls and terns
indicated the vicinity of land, which a few hours afterwards
was seen from the mast-head at a considerable distance. At
daylight on the 3d, we closed with its south-western end, and
dispatched two boats to make the circuit of the island, while
the ship ranged its northern shore at a short distance, and
waited for them off a sandy bay at its north-west extremity.

"We found that the island differed essentially from all others
in its vicinity, and belonged to a peculiar formation, very

few instances of which are in existence. ... The island is

five miles in length, and one in breadth, and has a flat sur-
face barely eighty feet above the sea. On all sides except

the north, it is bounded by perpendicular cliffs about fifty
feet high, composed entirely of dead coral, more or less porous,
honeycombed at the surface, and hardening into a compact cal-
careous substance within, possessing the fracture of secondary
limestone, and has a species of millepore interspersed through
it. These cliffs are considerably undermined by the action of
the waves, and some of them appear on the eve of precipitating
their superincumbent weight into the sea; those which are less
injured in this way present no alternate ridges or indication
of the different levels which the sea might have occupied at
different periods, but a smooth surface, as if the island,

which there is every probability has been raised by volcanic
agency, had been forced up by one great subterraneous convulsion.
The dead coral, of which the higher part of the island consists,
is nearly circumscribed by ledges of living coral, which pro-
ject beyond each other at different depths; on the northern side
of the island the first of these had an easy slope from the
beach to a distance of about fifty yards, when it terminated
abruptly about three fathoms under water. The next ledge had

a greater descent, and extended to two hundred yards from the
beach, with twenty-five fathoms water over it, and there ended

as abruptly as the former, a short distance beyond which no
bottom could be gained with 200 fathoms of line. Numerous
echini live upon these ledges, and a variety of richly coloured
fish play over their surface, while some cray-fish inhabit the
deeper sinuosities. The sea rolls in successive breakers over
these ledges of coral, and renders landing upon them extremely
difficult. It may, however, be effected by anchoring the boat,
and veering her close into the surf, and then, watching the
opportunity, by jumping upon the ledge, and hastening to the
shore before the succeeding roller approaches. In doing this
great caution must be observed, as the reef is full of holes,
and the rugged way is strewn with sea-eggs, which inflict very
painfull wounds; and if a person fall into one of these hollows,
his life will be greatly endangered by the points of coral
catching his clothes and detaining him under water. The beach,
which appears at a distance to be composed of a beautiful white
sand, is wholly made up of small broken portions of the differ-
ent species and varieties of coral, intermixed with shells of
testaceous and crustaceous animals.

"Insignificant as this island is in height, compared with
others, it is extremely difficult to gain the summit, in con-
sequence of the thickly interlacing shrubs which grow upon it,
and form so dense a covering that it is impossible to see the
cavities in the rock beneath. They are at the same time too
fragile to afford any support, and the traveler often sinks

into the cavity up to his shoulder before his feet reach the
bottom. The soil is a black mold of little depth, wholly formed
of decayed vegetable matter, through which points of coral every
now and then project.

"The largest tree upon the island is the pandanus, though there
is another tree very common, nearly of the same size, the wood
of which has a great resemblance to common ash, and possesses
the same properties. We remarked also a species of budleia,
which was nearly as large and as common, bearing fruit. It
affords but little wood, and has a reddish bark of considerable
astringency: several species of this genus are to be met with
among the Society Islands. There is likewise a long slender
plant with a stem about an inch in diameter, bearing a beauti-
ful pink flower, of the class and order hexandria monogynia.

We saw no esculent roots, and with the exception of the pandanus,
no tree that bore fruit fit to eat.'"' (Beechey 1831, I, 61-64).

A more succinct account was provided by Lieut. Peard, also on
board H.M.S. Blossom:

"On the 2nd December [1825 ] several Noddies and Boatswains'
birds were seen about the Ship, and we made Elizabeth Island
which like the last [ Ducie ] is of coral and uninhabited; but
I suppose 70 feet high and 16 or 18 miles in circumference.
The cliffs in many parts, more particularly the North part are

washed by the sea into curious and fantastic Arches, and large
caverns are formed into which the waves dash and force a passage
through wide openings in the top. A Beach of the most dazzling
whiteness and apparently composed of the finest sand every here
and there presented itself, and seemed to invite us to the
shore. Our boats however made the circuit of the Island and
found it by no means an easy access, some of the Officers landed
by wading through the Surf, and discovered that the beach was
composed of coral, madrepore and shells bleached by the sun."
(Gough, ed. 1973, 75).

LATER HISTORY

Apart from scientific investigations by visiting expeditions, much
of the later history of Henderson is connected with that of neighbour-
ing Pitcairn, discovered by Carteret in 1767 and settled by the Bounty
mutineers in January 1790. The settlers remained unaware of Henderson
until the arrival of the Elizabeth in 1819 (hence the currency of the
name Elizabeth on Pitcairn until at least mid-century), and did not
visit the island until 4-11 March 1843, according to the Pitcairn Island
Register (Murray 1854, 281). The visit led to 'a very unfavourable re-
port' on the island. The visit is described in some detail by Brodie
(1851, 17-18):

"Not long ago, eleven of these islanders, along with John

Evans (one of the three resident Europeans), were carried to
Henderson's, or Elizabeth Island, in an American whaling ves-
sel, on an exploring expedition. The landing was anything but
good, and the soil not near so rich as that of their own island,
being of a much more sandy nature. Water there appeared to be
none; but, after a long search, they found a fresh-water spring
below high-water mark. Some cocoa-nuts, which had been pur-
posely carried there, were planted upon the best ground they
could find. Several goats had been likewise shipped for turn-
ing out, but were actually forgotten until some time after

they were returned on board. They were only a few hours on the
island, and, therefore, were unable to form or give any detailed
description of it. Elizabeth Island is of a peculiar formation,
very few instances of which are known, viz., dead coral, more

or less porous, elevated in a flat surface, probably by vol-
canic agency, to the height of eighty feet. It is five miles

in length, one in breadth, and thickly covered with shrubs,
which makes it difficult to climb. It was called Henderson's
Island after the captain of the ship Hercules of Calcutta,
though first visited by the crew of the Essex, an American
whaler, two of whom landed on it after the loss of their ship,
and were subsequently taken off by an English whaler, who heard
of their fate at Valparaiso. They are very anxious to procure

a small vessel or large boat, of about twenty tons burden, to
enable them to visit this island at pleasure, and bring off
house-timber as required, as likewise to convert it into a run
for their live stock; thus relieving their little island from

that burden, and enabling them to direct the whole of its
capabilities to the use of man. They have established a sort
of Bank among themselves, in which a large part of the money
paid by vessels for refreshments, is suffered to accumulate
for the purpose of purchasing a small vessel."

The next visit from Pitcairn to Henderson did not take place until
16 August 1851:

"Twelve of the inhabitants sailed in the Joseph Meigs for the
purpose of visiting Elizabeth Island. On their arrival at the
island they discovered a human skeleton, and as nothing could
be found that may lead to discover who this unfortunate indi-
vidual was, it must remain a mystery." (Pitcairn Island
Register, in Murray 1854, 295).

This visit was followed by another on 11 November 1851:

"Thirty-eight of the inhabitants sailed in the ship Sharon, of
Fairhaven, for the purpose of visiting Elizabeth Island. On
Friday, 14th, after a boisterous passage of three days, they
‘landed upon Elizabeth Island, when they immediately set about
wooding the ship, and exploring the country, which is evidently

. of coral formation. The soil is very scanty, and totally un-

_f£it°for cultivation. Various specimens of marine shells are
dispersed all over the surface of the island, which, in combina-
tion with the thickly scattered pieces of coral, renders
travelling both difficult and dangerous. Water is found on the
north-west part of the island slowly dripping from the roof of
a cave, which cannot be reached without the aid of ropes. The
island rises about sixty feet above the level of the sea. Eight
human skeletons were also found upon the island, lying in caves.
They were doubtless the remains of some unfortunate seamen, as
several pieces of a wreck were found upon the shore." (Murray
1854, 295-296).

Since then, Henderson has been visited by Pitcairn Islanders on a fairly
regular basis, chiefly to cut miro wood, Thespesia populnea, from which
carvings are made for sale to visitors.

Formal possession of Pitcairn for the British Crown, as a British
Colony by settlement, was taken by Capt Russell Elliott, H.M.S. Fly, on
29 November 1838, and the island came under the administration of the
Western Pacific High Commission in 1898. Although Capt King, of the
Elizabeth, had informally raised the British flag on Henderson in 1819,
the island was not formally annexed (at the same time as Oeno and Ducie)
until 1902, when a party from Pitcairn raised the flag on 10 July. All
three islands were included with the administration of Pitcairn in 1938.
Pitcairn itself is governed by an Island Council, under the authority
of a Governor resident at the British Consulate-General in Auckland,
New Zealand. Henderson and the other two islands remain, of course,
uninhabited.

Table 1. Visitors to Henderson Island: summary

Date Visitor

1606 Quirés

29 Jan

1819 James Henderson

17 Jan Hercules

1819 Henry King

1 Mar Elizabeth

1819

20 Dec -

1820 Crew of the Essex

5 Apr

1825 F. W. Beechey

3 Dec H.M.S. Blossom

1827 Hugh Cuming

9 Oct

1838 Capt R. Elliott

29 Nov HeMsS:.. Ely

1843 First visit by

4-11 Mar Pitcairn islanders

1851 Second visit by

16 Aug Pitcairn islanders

1851 Third visit by

11 Nov Pitcairn islanders

1877 Wreck of Allen Gowie

13881 Grice, Summer & Co

1900 Ge Edis

1902 Visit by Pitcairn

10 July islanders

1907 Cem Cem Hililaise) Spal

Sept Arundel, A. E.
Stephen

1912 D. IR antes

Aug-Sept J. R. Jamieson

Activity

Discovery

Re-discovery

Survival

Survey
Biological
collections

Possession

Phosphate survey
Phosphate survey

Accession

Phosphate survey;
bird collection
Phosphate survey;

various collec-
tions

Main publication

Markham, ed. 1904;
Kelly, ed. 1966

King 1820

Gibbings, ed. 1935
Heffernan 1981

Beechey 1832
Hooker and Arnott 1841

St John 1940 and
various papers on shells

North 1908

Ogilvie-Grant 191l3a,
1913b; St John and
Philipson 1962; Tait
1912, Smith 1913

1922
Mar-Apr

1934
16-22
June

1937
Aug

1943
Nov.

1948
Aug

1957
3-4 Feb

1957
1971
Jan

1981

Whitney South Sea
Expedition

R. H. Beck, E. H.
Quayle, C. C. Curtis

Birds; plants

Mangarevan Expedi-
tion - H. St John,

F. R. Fosberg, E. C.
Zimmerman, C. M.
Cooke, D. E. Anderson

Plants, insects,
molluscs

J. R. Rivett- Survey
Carnac, H.M.S. Leander

Adm Richard E.
Byrd and party

Survey

Survey, light
built

Capt G.S. Webster
H.M.C.S. Awahou

W. H. Lintott Plants, birds

R. Tomarchin with
chimpanzee

H. A. Rehder, J. E.
Randall, Y. Sinoto

Archaeology,
marine biology

A. M. Ratliff(e?)

Survey

Murphy 1924a and later
papers; Brown 1931, 1935;
Brown and Brown 1935

St John and Philipson
1962

St John and Philipson
1962; Williams 1960

McLoughlin 1971

All the islands were visited during a defence reconnaissance by
H.M.S. Leander, Capt J. R. Rivett-Carnac, in August 1937, when Beechey's
chart of Henderson was revised and a flagpole raised. According to
Bourne and David (in prep.) further visits are said to have taken place
by United States parties in 1943 and 1966.

A light was erected on a steel tower 6.7 m tall at a height of 38
m by the Colonial Vessel Awahou, Suva, Capt G. J. Webster, on 11 August
1948. Because of maintenance difficulties it was abandoned in 1954
(this information is provided from Admiralty archives by Lt Cdr David).

SCIENTIFIC STUDIES

The first formal scientific studies were those carried out during
the visit of H.M.S. Blossom in 1825 when plant collections were made
and subsequently reported by Hooker and Arnott (1832) and Hemsley (1885).

On 9 October 1827 Mr. Hugh Cuming visited the island on a general
collecting trip, gathering specimens of plants, mollusk shells, and
various other groups of animals. He spent only one day there, according
to the following, from a letter to Wm. J. Hooker dated "March 21st,

SS 2s

"On the 9th made Elizabeth [ Henderson ] Island, a high coral
island without a lagoon, covered with shrubs and palms

Pandanus ] principally. Jessamines fi probably Jasminum
didymum ] and Laurels [ probably Pittosporum sp. with aromatic
foliage ] but few in flower. In the clefts of rocks collected
some fine ferns. On the llth made Pitcairn Island. ..." (St
John 1940).

During phosphate explorations in September 1907, A. E. Stephen col-
lected birds and made incidental observations, both reported by North
(1908). The first substantial study and collections, however, were
those carried out by D. R. Tait and J. R. Jamieson in August and Sep-
tember 1912. No full account of this investigation has appeared, but
birds were reported by Ogilvie-Grant (1913a, 1913b), marine molluscs
by Smith (1913), and plants by St John and Philipson (1962). Extracts,
at least, from Tait's diary and report exist in a manuscript letter to
Sir John Murray (1913).

The two major studies of the island are: (1) That of the Whitney
South Sea Expedition in March and April 1922. E. H. Quayle and C. C.
Curtis collected plants and birds, the former reported in Brown's Flora
of Southeastern Polynesia (1931-1935) and the latter in a wide range
of publications cited below. (2) The Mangarevan Expedition in 1934
spent the period 16-22 June on Henderson. H. St John and F. R. Fosberg
collected plants, reported by St John and Philipson (1962), E. C. ;
Zimmerman insects, and C. M. Cooke land molluscs. The invertebrate col-=
lections were reported in a wide range of systematic papers. No formal
ornithological observations were made during this visit, though notes
on birds were made, but not published, by Fosberg.

In 1957 W. H. Lintott visited Henderson with several Pitcairn Is-
landers on 3-4 February. His bird observations were reported by Williams
(1960) and his plant collections by St John and Philipson (1962). Fi-
nally, in January 1971, two brief visits were made by H. A. Rehder, J.

E. Randall and Y. Sinoto, aboard the Westward, during the National
Geographic Society-Oceanic Institute Expedition (which also made the
first comprehensive study of Ducie: Rehder and Randall 1975). It was
during this expedition that Sinoto made the first preliminary studies
of pre-European Polynesian habitation on Henderson.

GEOLOGY

Most writers on Henderson state that it is an elevated atoll with
original lagoonal summit depression preserved; some have speculated on
the recency of its uplift. It appears, however, to be very similar to
other makatea islands in the central and east Pacific, in which the main
limestones are broadly of mid-Tertiary age and in which the topography
results from post-uplift erosion. McNutt and Menard (1978) have sug-
gested that many of these islands have resulted from crustal loading
by an adjacent volcano, which in the case of Henderson would be Pitcairn.
Pitcairn stands only 347 m above sea-level, but rises 3.5 km from the
ocean floor. Two phases of surface vulcanism have been identified, with
K-Ar ages of 0.46-0.63 and 0.76-0.93 million years (Duncan et al. 1974).
The total span of volcanism for the whole Pitcairn cone must be much
greater, however, and the crust on which it stands has an age of roughly
30 million years. McNutt and Menard (1978) calculate the amount of
uplift of Henderson caused by the Pitcairn loading to be 32 m (compared
with an actual uplift which they state to be 30 m); Oeno and Ducie are
not uplifted, because the former is in Pitcairn's moat and the latter
beyond the arch.

The location of Henderson along a prolongation of the Tuamotu-
Gambier axis has already been mentioned. Basalts at Mururoa in the
eastern Tuamotus have been dated at 6-8 million years at a depth of
438 m (Labeyrie et al. 1969). The surface volcanics of the Gambier
Archipelago (maximum elevation 441 m) are also of similar age (4.77-
5.98 m yr: Bellon 1974; 5.33-7.15 m yr: Brousse et al. 1972). These
and the dates for Pitcairn suggest a volcanism migration rate of 11
cm/yr.

It seems likely that the limestones of which Henderson are com-
posed are of late Tertiary age, and may have been exposed for a few
million years. The ‘lagoonal' topography may well be a karst erosion
feature, and the columns and pinnacles within the depression also karst
features rather than patch reefs. The low-lying areas surrounding the
high core at least on the leeward side could (by comparison with makatea
islands elsewhere) be a last interglacial reef.

Actual geological investigations of Henderson are limited to pros-
pecting for phosphate deposits. The first such survey was carried out
in 1881 by Grice, Summer and Co of Melbourne (then lessees of Malden) ;
they found only 200 tons of guano. A permit to exploit was held by
Capt J. Rasmussen during 1903-1907, but was not taken up. G. C. Ellis

and J. T. Arundel of the Pacific Phosphate Company, aboard the Tyrian,
made a brief survey in 1907. No useful deposits were found, but

Hutchinson (1950, 213) quotes analyses of two samples with Ca3P50
contents of 8.5 and 18.0% respectively.

In 1908 a twelve-month license to prospect on Henderson, Oeno and
Ducie was issued to James Banks and James Watt, who made a preliminary
visit to the first of these (these details are derived from papers in
the Ministry of Defence Hydrographic Department archives very kindly
made available by Lt Cdr A. C. F. David to Dr W. R. P. Bourne, who drew
them to our attention). A license for them to exploit guano was issued
to them on 14 December 1909, to extend from 1 April 1912 to 31 March
1924, with the right to occupy the island, erect buildings, and to cut
and use timber and other vegetable growth, and the obligation to plant
quick-growing trees on two conspicuous points, and to erect a beacon
25 ft high. Banks visited Henderson in July 1912 at the time of the
survey of the island by D. R. Tait and J. R. Jamieson. On 11 October
1912 the rights were transferred to a new company, Henderson Island
Limited, under the chairmanship of Sir John Murray, and Banks became
the Company's agent. During this survey a house and six sheds were
built of corrugated iron to house the survey party. Tait's own report,
dated 20 January 1913, in the Hydrographic Office archives, was ex-
tremely disappointing, and on 30 January Watt reported the Company's
intention to give up the lease: 'the island was useless not only in
regard to the supply of phosphates, but for any other purpose.' The
lease was accordingly terminated, and the Company dissolved.

VEGETATION AND FLORA

What was evidently Pandanus was reported at Henderson by Munilla
during the Quit6és expedition in 1606, and again by Beechey in 1825.
The first collections were made by Lay and Collie during the Beechey
expedition: four species were reported from these collections by Hooker
and Arnott (1841, 64-69) and three more by Hemsley (1885, 15). These
were:

Asplenium nidus L. (in Hemsley 1885, 15)

Euphorbia sparrmannii Boiss. (as E. ramosissima Hooker and
Arnott, the Henderson specimen being their type)

Glochidion pitcairnense (F.Br.) St. J. (as Bradleia? glochidion
in Hooker and Arnott 1841, 69)

Tournefortia argentea L. (in Hemsley 1885, 15)

Canthium odoratum (Forst.f.) Seem. (as Chiococca odorata in
Hooker and Arnott 1841, 65)

Guettarda speciosa L. (in Hemsley 1885, 15)

Ixora fragrans (Hooker and Arnott) Gray (as Cephaelis? fragrans
in Hooker and Arnott 1841).

Since then, four major collections of plants have been made. First,
D. R. Tait collected 91 numbers representing 55 species in August-

September 1912; the collection was determined by St John nearly fifty
years later (St John and Philipson 1962). Second, E. H. Quayle and C.
C. Curtis collected some twenty species, including four ferns, during
the Whitney Expedition in 1922. This material was included in Brown's
Flora of Southeastern Polynesia (Brown 1931, 1935; Brown and Brown 1935),
where Santalum hendersonense was described as a Henderson endemic. Most
of the Whitney collections were also cited by St John and Philipson
(1962), though curiously these authors do not include the Whitney Ex-
pedition in their list of botanical collections. Third, large collec-
tions were made by St John and Fosberg during the Mangarevan Expedition
in 1934, and published both in numerous systematic papers and as a com-
prehensive listing by St John and Philipson (1962). Finally, W. H.
Lintott collected 25 species in 1957, and these too were reported by

St John and Philipson (1962). St John and Philipson mention that J.

H. Maiden collected 'a few common species', said to be reported in his
1896 paper on Pitcairn, but this paper does not in fact mention Hender-
son plants.

The flora listed by St John and Philipson (1962) includes 8 ferns
and 55 angiosperms; to these should be added Sesuvium portulacastrum L.,
and Capparis sandwichiana DC. collected during the Whitney Expedition
and by Lintott, and inadvertently omitted from their list. The plants
are listed with some revision of nomenclature in Appendix 1. In addi-
tion to the main listings by Brown (1931, 1935), Brown and Brown (1935),
and St John and Philipson (1962), Henderson plants collected by the
Mangarevan Expedition have been included in many systematic papers,
notably by Copeland (1938), five species of ferns; Skottsberg (1937),
two species of Liliaceae; von Poellnitz (1936), Portulaca; Skottsberg
(1938), Santalum; Heimerl (1937), Peperomia; and Sherff (1937), Bidens.
It is of interest that no less than eight species, or 12 per cent of
the recorded flora, have only been collected on one occasion, by D. R.
Tait in 1912.

Six species and five varieties of angiosperms are described as
endemic to Henderson, not including the new variety of Korthalsella
margaretae defined by Brown (1935) but reduced to K. vitiensis by St
John and Philipson (1962, 180), or the new variety Polypodium . euro-
phyllum C. Chr. var. hendersonianum E. Br. (in Brown and Brown 1931)
which they reduce to Microsorium vitiense (Baker) Copeland. The endemic
species and varieties presently accepted are:

Peperomia hendersonensis Yuncker (in Yuncker 1937, 16-17)

Celtis paniculata Planch. var. viridis F. Br. (in Brown 1935,
32)

Santalum hendersonense F. Br. (in Brown 1935, 66)
Myrsine hosakae St John (in St John and Philipson 1962, 189-190)

Nesoluma st-johnianum H. J. Lam and Meeuse (in Lam and Meeuse
1938, 153-154)

Geniostoma hendersonense St John (in St John and Philipson 1962,
190)

Heliotropium anomalum Hooker and Arnott var. candidum St John
(in St John and Philipson 1962, 192)

Canthium barbatum (Forst. f.) Seem. var. christianii Fosb.
forma calcicola Fosb. (in Fosberg 1937)

Bidens hendersonensis Sherff (in Sherff 1937, 6)
var. hendersonensis Sherff (in Sherff 1937, 6)
var. subspathulata Sherff (in Sherff 1937, 7)

Comments on some of these species are given in Appendix 1. Other taxa
originally defined from Henderson Island material, but not endemic to
the island, include Euphorbia ramosissima Hooker and Arnott (= E.
Sparrmannii Boiss. in Appendix 1), Cassia glanduligera St John (in St
John and Philipson 1962, 181-184), also in the Australs; and Dianella
intermedia Endl. var. gambierensis F. Br. (in Brown 1931, 152), also
on Mangareva.

Four adventive species are listed:

Cocos nucifera. This is recorded as being planted as early as
1843 by the Pitcairn Islanders (Brodie 1851, 17). Trees
were found by Stephen in 1907 (North 1908), by Bank (1909)
(a dozen trees divided between the north and west landings),
and by Tait (1912). Collected by the Mangarevan Expedition
in 1934, when Fosberg noted that the trees were ‘all young’.
Probably repeatedly planted by the Pitcairn Islanders over
the years.

Cordyline terminalis, collected only by the Mangarevan Expedi-
tion in 1934, when Fosberg noted half a dozen plants.

Aleurites moluccana, collected only by the Whitney Expedition
in 1922.

Achyranthes aspera, collected only by Tait in 1912, and the only
one of the four not a deliberate introduction.

In addition James Bank in his report of 5 January 1909 records plant-
ing limes and oranges, and these are mentioned, together with potatoes,
by Maude (1951, 63).

Besides the vascular plants, the Mangarevan Expedition also col-
lected three species of Fungi, five lichens and ten bryophytes, all
listed by St John and Philipson (1962). An earlier list of the bryo-
phytes was given by Bartram (1940).

MAMMALS

There are no native mammals on Henderson. Several have, however,
been landed since the island was discovered. Goats were first taken
to Henderson from Pitcairn in 1843, but through inadvertence were not
landed before the vessel left (Brodie 1851, 17). Three were, however,
released during the visit of the Whitney Expedition in 1923 (Beck 1923),
but had disappeared by the time of the Mangarevan Expedition in 1934.

Pigs were landed by D. R. Tait in 1912, but of these there is no sub-
sequent record. Mice are mentioned as being numerous at the north land-
ing by James Bank (1909), but are not otherwise recorded. The only
Numerous introduced mammal is the Polynesian Rat. King (1820) found it
there in 1819. Bank mentioned it as numerous at the north landing in
1909, and Stephen had also found it present in 1907 (North 1908). Speci-
mens were collected by the Whitney Expedition and listed under Rattus
exulans (Peale) by Tate (1935).

BIRDS

The Quirdéds expedition recorded seabirds in the neighbourhood of
Henderson - Gaspar de Leza specifies 'grey gulls and terns" - in January
1606. Much later, in 1819, King (1820) recorded a parrot and a few
pigeons, and later in the same year the castaways from the Essex re-
corded tropicbirds in holes, with young and eggs, and also 'small birds,
about the size of a blackbird', roosting in the trees (Gibbings, ed.
1935, 55, 79).

The first collections of birds, however, were made by A. E. Stephen
in 1907, and the specimens described by North (1908). D. R. Tait and
J. R. Jamieson also made collections in 1912, and these were reported
by Ogilvie-Grant (1913a, 1913b). The major contribution to the orni-
thology of Henderson was, however, the Whitney Expedition in 1922, which
resulted in a long series of papers referred to below. Subsequently,
W. H. Lintott made some observations in 1957, and these were incorporated
in Williams's (1960) paper on the birds of Pitcairn.

A comprehensive summary of knowledge of the birds of Henderson is
in preparation by Bourne and David. This section therefore simply keys
the published literature on the seabirds, shorebirds and land birds,
and the manuscript records by Beck and Quayle of the Whitney Expedition.
Nomenclature follows that of du Pont (1976) who listed most or all of
the birds known from the island.

Seabirds
Pterodroma ultima Murphy Murphy's Petrel, Oeno Petrel
Recorded by du Pont (1976).
Pterodroma neglecta (Schlegel) Kermadec Petrel

Collected by Beck and Quayle in 1922.

Recorded by Murphy and Pennoyer (1952, 27); as breeding by Williams
(1960). P. ultima and P. neglecta are regarded as distinct by Williams

and du Pont (1976) and both recorded by them for Henderson.

Pterodroma alba (Gmelin) Phoenix Petrel

Collected by Quayle and Beck in 1922, called Henderson Petrel.

Recorded by Murphy and Pennoyer (1952,33); and as breeding by
Williams (1960) and King (1967).

Pterodroma arminjoniana heraldica (Salvin) Herald Petrel

Recorded by Murphy and Pennoyer (1952, 39); and as breeding by
Williams (1960) and King (1967).

Puffinus nativitatis Streets Christmas Shearwater

Shearwaters of undetermined species were recorded as 'very plenti-
ful' by Stephen in 1907 (North 1908). This species recorded as probably
breeding by Williams (1960) and King (1967). Apparently not collected
on Henderson by the Whitney Expedition in 1922.

Puffinus pacificus pacificus (Gmelin) Wedge-tailed Shearwater
Collected by Beck in 1922.
Recorded as breeding by Murphy (1951) and Williams (1960).
Gygis alba candida (Gmelin) White Tern

Noted as 'plentiful' and egg reported by Stephen in 1907 (North
1908). Recorded as G. candida (Gmelin) by Ogilvie-Grant (1913a, 1913b).
Collected and noted as a white-footed form by Quayle and Beck in 1922.
Recorded as breeding by Williams (1960).

Anous stolidus pileatus (Scopoli) Common Noddy

Noted as 'not so plentiful’ by Stephen in 1907 (North 1908). Re-
corded as A. leucocapillus (Gould) by Ogilvie-Grant (1913a, 1913b).

Collected by Beck and Quayle but not common in 1922. Recorded as breed-
ing by Williams (1960) and Baker (1951).

Anous tenuirostris minutus Boie Black Noddy
Rare, one collected by Beck or Quayle in 1922.

Procelsterna coerulea skottsbergii Bonaparte Blue-grey Noddy,
Grey Ternlet

Seen and collected by Beck and Quayle in 1922, not common. Re-
corded as P. coerulea (Bennett) by Ogilvie-Grant (1913a, 1913b) and as
P. c. skottsbergii in Peters (1934). Recorded as breeding by Williams
(1960).

Phaethon rubricauda subsp. (Gmelin) Red-tailed Tropicbird

Recorded as breeding by Beck in 1922, and Williams (1960), based
on local reports.

Sula dactylatra personata Gould Masked Booby

One individual collected by Quayle in 1922. Recorded as common,
with chicks, in January 1957, by Lintott (Williams 1960).

21
Sula leucogaster plotus (Forster) Brown Booby
Sight record in 1957 recorded by Williams (1960).
Sula sula rubripes Gould Red-footed Booby

Recorded by Ogilvie-Grant (1913a, 1913b) (as S. piscator) and by

Murphy (1936); noted as probably breeding by Williams (1960). Henderson
specimens were included by Grant and Mackworth-Praed (1933, 118) under
their new species §. nicolli, but this is now regarded as a colour phase
of S. sula.
Fregata minor subsp. (Gmelin) Greater Frigatebird

Described as ‘numerous’ by Stephen in 1907 (North 1908). Seen and
collected by Beck and Quayle in 1922. Recorded as probably breeding by
Williams (1960), based on local information.

Shorebirds

Numenius tahitiensis (Gmelin) Bristle-thighed Curlew

Summer migrant, collected by Quayle and Beck in March-April 1922
(Stickney 1943).

Heteroscelus incanus incanus (Gmelin) American Wandering Tatler
Summer migrant, recorded in March-April 1922 (Stickney 1943).
Calidris alba (Pallas) Sanderling

Recorded by Stephen in 1907 (Ogilvie-Grant 1913a, 1913b); seen
but not collected by Quayle in 1922.

Wading birds
Egretta sacra sacra Gmelin Reef Heron
One individual seen by Beck and Quayle in 1922.
Land birds
Porzana atra North Henderson Island Rail, Henderson Island Crake
Collected by Stephen in 1907, who noted it as 'plentiful', and
described as Porzana atra n.sp. Black Water Crake by North (1908). Col-
lected by Tait in 1912 and independently described by Porzana murrayi
n.sp. by Ogilvie-Grant (1913a), a name abandoned by Ogilvie-Grant

(1913b). Recollected in 1922 by Quayle and Beck of the Whitney Expedi-
tion and assigned to a new endemic genus as Nesophylax ater (North) by

Murphy (1924). Described under North's name, with a colour plate, by
Ripley (1977, 235, plate 29), without reference to Murphy (1924). Listed
as breeding by Williams (1960).

The widespread and closely related Porzana t. tabuensis Spotless
Crake occurs on nearby Oeno (Murphy 1924, Amadon 1942, Williams 1960).

Ptilinopus purpuratus insularis (North) Henderson Island Fruit
Pigeon

Described in flocks of twenty or more by Stephen in 1907, and named
as Ptilopus insularis n.sp. by North (1908). Collected by Tait in 1912
and described as Ptilopus coralensis Peale by Ogilvie-Grant (1913a).
Listed as Ptilopus insularis North by Ogilvie-Grant (1913b). The Whitney
collections in 1922 were listed under the same name by Murphy (1924).
Named as an endemic subspecies of Ptilinopus purpuratus (Gmelin), widely
distributed in the Societies and the Tuamotus, by Ripley and Burckhead
(1942). Listed as still common and breeding by Williams (1960).

Vini stepheni (North) Henderson Island Parrot

Noted as 'not very plentiful' by Stephen in 1907, and described as
Calliptilus(?) stepheni n.sp. by North (1908). Collected by Tait in
1912 and described as Vini hendersoni n.sp. by Ogilvie-Grant (1913a).
Named as Vini stepheni (North), with a colour plate, in Ogilvie-Grant
(1913b). Collected by Beck and Quayle of the Whitney Expedition in 1922
and said to be common; and listed by Amadon (1942). Listed as breeding
but apparently not very common by Williams (1960). An endemic species.

Acrocephalus vaughani taiti (Ogilvie-Grant) Henderson Island Warbler

Collected by Tait in 1912 and named Acrocephalus taiti n.sp. by
Ogilvie-Grant (1913a, 1913b). Collected by Quayle and Beck of the
Whitney Expedition in 1922, said to be very common; and listed as
Conopoderas vaughani taiti (Ogilvie-Grant) by Murphy and Mathews (1929).
Listed as breeding by Williams (1960), who also notes the presence of
A. v. vaughani (Sharpe) on Pitcairn. An endemic subspecies.

REPTILES

Lizards were apparently first observed by Stephen in 1907, when he
found them 'very plentiful' (North 1908). Six skinks were collected by
the Whitney Expedition in 1923 and listed by Ortenburger (1923) and later
by Burt and Burt (1932) as Emoia cyanura (Lesson), a widespread species.
A gecko has been seen but we do not know of specimens or an identifica-
tion. The green sea turtle, Chelone mydas (L.), comes ashore to lay its
eggs on the few beaches (Quayle 1922).

TERRESTRIAL ARTHROPODA

No special effort has ever been made to collect any of the Hender-
son Island arthropods, except the insects, which were gathered by
Zimmerman in 1934. Even this can only be regarded as preliminary, being
the results of one man's work for only six days. A longer, less hurried
effort, with light traps, Berlese funnels and other special methods,
could be expected to yield a tremendous increase in the known inverte-
brate fauna of the island.

A discussion written by Dr. Frank G. Howarth, of B. P. Bishop
Museum, Honolulu, states the case very well:

"The [terrestrial ] arthropod fauna of Henderson I. is still quite
poorly known. Only about [40] species have been recorded to date, of
which about [a third] are likely endemics. Judging from the recorded
lushness and diversity of the flora, the insect fauna should be at least
an order of magnitude greater. Zimmerman (1935) wrote that a number of
endemic species were collected during the week's stay of the Mangarevan
Expedition. Apparently, only a few taxonomic groups have been worked
up from those collections, as only 15 families of arthropods are repre-
sented in the published records. Based on the known faunas of other
small Pacific islands, one would expect to find at least 100 families
and a total arthropod fauna of a few hundred species of which approxi-
mately 50% would be endemic to Henderson or perhaps also to Pitcairn I.
For example, there are apparently no published records of Lepidoptera
(moths), which is second only to the Coleoptera in numbers of species
on other Pacific islands. Neither are there any records for Collembola,
Orthoptera, Myriapoda, or native Hymenoptera, all of which should be ex-
pected there.

"Many insects and relatives are probably endemic to the Pitcairn
Group. As the fauna and flora on the inhabited island of Pitcairn it-
self become more ravaged by goats and other man-caused perturbations,
Henderson Island will become more important as a refuge or Noah's Ark
for many of these restricted species.

"A number of special habitats, which undoubtably occur there, have
not been faunistically surveyed. For example, being a raised coralline
island a subterranean fauna should exist there, of which the aquatic or
"anchialine' underground fauna should be especially well developed with
Many native species. A significant terrestrial cave fauna may also have
evolved there.

"Distant described 3 new species of Issidae in 1913, and none of
these species have been subsequently reported on again. Their status
may be problematical. Fennah, 1958, reviewed the fulgorid fauna of SE
Polynesia but apparently missed Distant's 1913 paper (!). Fennah de-
scribed a 4th Issidae as an endemic subspecies with the type subspecies
endemic to Pitcairn I. Zimmerman collected a nice series of Catacanthus
taiti on the Mangarevan Expedition. The species is still known only
from Henderson (based on our collections). Related species occur in the
Society and Marquesas Is., and based on the impressive, conspicuous size
and color of C. taiti, the fact that it hasn't been found elsewhere, sug-
gests that it is endemic. Both Coleotichus and Ugyops have many native
restricted species in the Pacific, thus, it is probable that these un-
identified specimens represent at least native species, and may be en-
demic. The weevils are among the best known groups of arthropods in
the Pacific; therefore the 2 listed species are undoubtedly endemic and
are of special interest to biogeographers, evolutionists, ecologists and
others.

"Based on the above lack of entomological data and the possibility
of environmental disturbance, if not by the current venture then by some
fool liberating goats or the like, I think it is abundantly clear that
we should attempt to launch or assist in a modern entomological/ecologi-
cal expedition to this island to fill this critical lacuna. Of equal
import to science is the predictable occurrence of excellently preserved
and highly significant paleontological material in the limestone sink-
holes."

Insecta

Stephen found a butterfly abundant in 1907 (North 1908), and Tait
states that he sent insects to the British Museum (Natural History) in
1912, but of these we have found only a few published records (Distant
1913). Otherwise most of the insect records published for Henderson
are of collections made by Zimmerman on the Mangarevan Expedition in
1934. According to Frank J. Radovsky (in litt.) there are at least 33
species of insects recorded from the island, of which 11 (acc. Frank G.
Howarth in litt.) are, so far as known, endemic. We are only able to
give a partial list of these, with sources.

Thysanoptera

Thrips albipes Bagnall (in Moulton 1939).
Rhynchota

Atylana parmula thalna Fennah (1958). Endemic.

Catacanthus taiti Distant (1913). Endemic.

Coleotichus sp. (Distant 1913), Possibly endemic.

Devagama fasciata Distant (1913). Endemic.

Devagama insularis Distant (1913). Endemic.

Devagama maculata Distant (1913). Endemic.

Lallemandana insignis insignis (Distant) (Hamilton 1980). Endemic.

Peregrinus maidis Ashmead (Fennah 1958).

Ugyops sp. (Fennah 1958). Possibly endemic.

Coleoptera
Hypothenemus eopolyphagus Beeson (1940).
Microcryptorhynchus orientissimus Zimmerman (1936). Endemic.

Nesonos brunneus Zimmerman (1938).

2S)

Notioxenus cylindricus Jordan (Zimmerman 1938).

Rhyncogonus hendersoni Van Dyke (1937). Endemic.

Stephanoderes pacificus Beeson (1940).

Stephanoderes vafer Blandford (Beeson 1940).
Hymenoptera

Cardiocondyla nuda Mayr subsp. nereis Wheeler (1936).

Monomorium floricola (Jordan)(Wheeler 1936).

Tapinoma melanocephalum (Fabr.) var. australe Santschi (Wheeler 1936).

Technomyrmex albipes (F. Smith) (Wheeler 1936).

Tetramorium guineense (Fabr.)(Wheeler 1936).

Nylanderia vaga Forel var. crassipilis Santschi (Wheeler 1936).
Diptera

Dacus setinervis Malloch 1938 (Drew 1975).

Arachnida

Three species of spiders collected by the Mangarevan Expedition are
listed for Henderson by Berland (1942):

Thorellia ensifera (Thorell)

Theridion paumotui Berland

Cyrtophora moluccensis Doleschall.
Crustacea

No land crabs have been recorded from Henderson. A very large
cenobite, perhaps Birgus, was captured by a member of the party in 1934,
but the specimen may not have been saved. Four species of terrestrial
isopods, none of them endemic, are recorded from Mangarevan Expedition
collections by Jackson (1938). They are Philoscia truncata Dollfus,

P. fasciata Jackson, Spherillo montivagus Budde-Lund, and S. marque-
sarum Jackson.

LAND MOLLUSCA
Land Mollusca were collected by C. Montague Cooke, Jr., during the
Mangarevan Expedition. One species was previously recorded, but at least
12-15 additional species were found (Cooke 1934, 44). Cooke and Kondo
(1960, 256) estimated the fauna at 18 species. The following records
have been published:

Achatinellidae

Tornatellides (Tornatellides) oblongus parvulus n. subsp.
(in Cooke and Kondo 1960, 255), endemic subspecies.
Tubuaia hendersoni n.sp. (in Kondo 1962, 36-38), endemic species.
Endodontidae
Minidonta hendersoni n.sp. (in Solem 1976), endemic species.
Helicarionidae
Diastole (Diastole) glaucina Baker (in Baker 1938, 50), endemic
species;
Helicinidae

Orobophana solidula (Gray) (in Cooke and Kondo 1960, 255).

In addition, Cooke and Kondo (1960, 256) mention specimens from
Henderson in the following genera: Elasmias, Lamellidea and Torna-
tellinops (Achatinellidae); Syncera (= Assiminea) (Assimineidae) ;

Melampus (Ellobiidae); Georissa (Hydrocenidae); Nesopupa and Pupisoma
(Pupillidae); and Thaumatodon.

MARINE FAUNA

As mentioned above, the schooner Westward made only brief stops at
Henderson Island on her trip from Pitcairn to Ducie Atoll and back.
Actually only one full day and two afternoons were spent there, and the
only extensive collection made was of mollusks.

Fishes

The diving group spent their time searching for and collecting
fishes and checking for the presence of Acanthaster planci (Linnaeus),
the Crown-of-Thorns. J. E. Randall (pers. comm.) received the impres-
sion during the diving operations that the fauna was richer than that
of Ducie (Rehder and Randall, 1975, 21-26). He has made no list of
species collected and seen, feeling that such a list would be without
value considering the shortness of the stay at the island.

Mollusks
See Appendix 2.
Other Invertebrates

No. material other than mollusks were collected during the Westward
visit, in large measure due to the absence of Dennis M. Devaney during
this segment of the trip. One noteworthy comment is that no specimens
of Acanthaster planci were seen by the divers despite the fact that one
of the programs carried out on the Westward was a survey of the presence
of the Crown-of-Thorns in southeastern Polynesia. Beechey (1833, 49)
mentions the presence of ‘numerous echini' on the reef flat, probably
Diadema savignyi Michelin or D. setosum (Leske), as he comments on their
capability of inflicting ‘painful wounds."

Beechey also mentions seeing some '‘cray-fish' in the cavities on
the reef (Panulirus species).

SCIENTIFIC IMPORTANCE AND CONSERVATION

: Access to Pitcairn Island (and thus to other islands of the group)
requires a license issued by the Office of the Commissioner for Pitcairn,
issued by the Governor after the visit has been approved by the Pitcairn
Island Council; casual visitors may land at the discretion of the Island
Magistrate. There are no conservation measures applicable to Pitcairn

or to its associated islands. In 1969 Henderson, Ducie and Oeno were

all included in a list of Pacific islands proposed for international sci-
entific supervision, possibly under the proposed ‘Islands for Science'
Convention (Douglas 1969, 463). No action was taken on this proposal.

In 1982 it became known that proposals had been made to the British
Government by a wealthy American citizen, who wished to take up residence
on Henderson in exchange for development assistance on Pitcairn. This
proposal, when it became known, led to considerable concern in the sci-
entific community, which was openly voiced at the XVth Pacific Science
Congress in Dunedin, New Zealand. Appendix 3 gives the text of a reso-
lution on Henderson Island adopted at this Congress.

There has been a growing interest in island biology, first taking
on a scientific character with the work of Charles Darwin, but in the
last few decades receiving greater and greater scientific attention.
One of the preoccupations of this interest has been to determine what
the conditions were on different types of islands before humans and
especially before Europeans arrived and brought about drastic changes
in the nature and functioning of these ecosystems. Very inadequate
historical evidence exists, and for most islands none at all. In Hen-
derson we have, preserved, a fine example of one of the most interesting
types of island. It has the advantages of being small and remote, and
of having a simple enough biota that its relationships, processes and
functioning may possibly be understood with adequate investigation.

It is certain that undescribed species exist, especially of smaller
and less conspicuous animals. It is equally certain that many of the
species inhabiting the island, known or unknown, are threatened by the
proposed disturbances, and will immediately become endangered if the de=
velopment project is carried forward. The amount of attention being
given to endangered species at present indicates that, whether for philo-
sophic or practical reasons, a real value is attached to our co-inhabitants
of the globe by the better elements of our Western culture. This should
not lightly be brushed aside.

The study of islands as microcosms of more complex ecosystems has
the practical significance of enabling us to gain some insight into the
functioning of the larger and infinitely more complex ecosystems in which
the majority of humanity live. Hence it would seem folly to permit the
destruction of the only remaining intact example of one of the most im-
portant classes of islands that could form an important component of this
study. Even its very scarcity or uniqueness would seem to enhance its
value, as it does with so many other, mostly less important things.

ACKNOWLEDGEMENTS

Most of the text and compilation is the work of the authors, but we
wish to express our thanks to W. R. P. Bourne, C, C. Christensen, Lt
Cdr A. C. F. David, Frank G. Howarth, Frank J. Radovsky, Harald A.
Rehder, and Yosi Sinoto for substantial contributions of information,
and to Lenore Smith for typing the manuscript.

Note

While the present report was being assembled, other naturalists
expressed their concern for the future of Henderson Island natural eco-
systems in the following report:

Serpeli J. ,. Collards IN.) Davis Sia vand aWelllis 7S uel 98eer
Submission to the Foreign and Commonwealth Office on the future
conservation of Haiderson Island in the Pitcairn Group. London:
World Wildlife Fund-UK, International Union for Conservation of
Nature and Natural Resources, and International Council for Bird
Preservation. 26 pp.

The need for more adequate knowledge of the biota and ecology of
Henderson Island is of such urgency that the Smithsonian Institution,
in cooperation with the Royal Society, is actively planning a biological
and geomorphological survey of the island, to take place during 1984 if
the necessary permits can be secured and funds can be raised.

29
Appendix 1. A revised list of the vascular plants of Henderson Island.

No additional collections have come to our attention since the ac-
count of the flora by St John and Philipson (1962) was published, but
much work has been done on the Pacific flora since then, and some names
have been changed. Two species collected by Lintott were inadvertently
omitted by St John and Philipson. Also our concepts of some taxa differ
from those of the authors of that account. Such revisions and changes
are presented, with a few explanatory remarks and comments, in the fol-
lowing list.

Asplenium lobulatum Mett.

Asplenium nidus L.

Asplenium obtusatum Forst.f.

Davallia solida (Forst.f.) Sw.

Nephrolepis biserrata (Sw.) Schott

Nephrolepis exaltata (L.) Schott

Perhaps an alternative identification of the preceding.

Cyclophorus blepharolepis C. Chr.

Polypodium vitiense Baker

Microsorium vitiense (Baker) C. Chr.

Polypodium euryphyllum var. hendersonianum E. Br.

We do not see much to be gained from extreme segregation
of the genus Polypodiun.

Polypodium scolopendria Burm.f.

Phymatodes scolopendria (Burm.f.) Ching
Pandanus tectorius Parkinson

Pandanus sp. of St John and Philipson (1962)
Lepturus repens (Forst.f.) R. Br.
Thuarea involuta (Forst.f.) R. and S.

Henderson is the eastern extreme of this widespread Indo-
Pacific beach grass.

Fimbristylis cymosa R. Br. (s.1.)
Fimbrystylis sp. of St John and Philipson (1962)

*Cocos nucifera L.
A few trees, originally planted.
*Cordyline fruticosa (L.) Chev.
Cordyline terminalis (L.) Kunth
(Cordyline fruticosa Goepp.) (nom. nud.)

This has frequently been called C. terminalis under the as-
sumption that C. fruticosa (L.) Chev. is an illegitimate later

homonym of C. fruticosa Goepp., but that was based only on a
reference to a name Dracaena fruticosa H. Berol. that was ap-
parently never published.

Dianella intermedia var. gambierensis F. Br.

Peperomia hendersonensis Yuncker
Endemic to Henderson.

Celtis paniculata var. viridis F. Br.

Procris pedunculata (Forst.) Wedd.

Korthalsella rubescens (v. Tiegh.) Lecomte

Korthalsella vitiensis (v. Tiegh.) Engler

Santalum hendersonense F. Br.

Endemic to Henderson.

*Achyranthes aspera var. pubescens (Moq.) Townsend

From the brief descriptive remarks by St John and Philipson
(1962) this seems to be the widespread var. pubescens (Moq.)
as defined by Townsend, Kew Bull. 29 (1974), 473.

Boerhavia tetrandra Forst.f.

Boerhavia diffusa var. tetrandra (Forst.f.) Heimerl

*Species thus marked are introduced.

31
Pisonia grandis R. Br.
Portulaca lutea Sol. ex Forst.f.
Sesuvium portulacastrum L.

Represented by Lintott H 22 (CHR), not listed by St John and
Philipson (1962).

Cassytha filiformis L.
Hernandia sonora L.

Capparis sandwichiana DC.

Represented by Lintott H 24 (CHR), not listed by St John and
Philipson (1962).

Lepidium bidentatum Mont.
Pittosporum arborescens Rich. ex Gray
Caesalpinia bonduc (L.) Roxb.

Cassia glanduligera St John

Close to and formerly considered identical with C. gaudi-
chaudii H. and A., of Hawaii. C. glanduligera is also known
from the Austral Islands.

Sesbania coccinea (L.f.) Poir.
Sesbania speciosa (Soland.) R. Br. var. tuamotuensis R. Br.
Sesbania atollensis St John

The specimen, Lintott H 1 (CHR) on which the Henderson Island
record of Sesbania atollensis St John is based could not be lo-

cated at Christchurch in 1983 according to Miss B. M. Macmillan
(pers. comm.).

Suriana maritima L.
*Aleurites moluccana (L.) Willd.

Euphorbia sparrmannii Boiss.

Euphorbia ramosissima H. and A. (non Loisel.)

Glochidion tahitense var. pitcairnense F. Br.

Endemic to Henderson and Pitcairn Islands.

Triumfetta procumbens Forst.f.
Thespesia populnea (L.) Sol. ex Correa
Xylosma suaveolens subsp. haroldii Sleumer
Pemphis acidula Forst,
Eugenia rariflora Benth.
Meryta brachypoda Harms
Endemic to Henderson and the Austral Islands.
Myrsine hosakae St John
Endemic to Henderson; tree 7 m tall.
Nesoluma st-johnianum Lam and Meeuse
Endemic to Henderson,
Geniostoma hendersonense St John

Tree 3-8 m tall; endemic to Henderson. Beechey's (1825,
63-64) ‘species of budleia'.

Jasminum didymum Forst.f.
St. John (1940) suggests that Cuming's "Jessamine" may be
this, but does not include it in the 1962 paper. We have no
definite record based on a specimen. No complete list of Cum-

ing's "Elizabeth Island" plants has come to our attention.

Alyxia stellata (Forst.) R. and S.

Ipomoea macrantha R. and S.
Ipomoea grandiflora sensu F. Br. non (Choisy) Hallier
Ipomoea glaberrima Bojer

Cordia subcordata Lam.

Heliotropium anomalum var. candidum St John

Endemic to Henderson.

Tournefortia argentea L.f.
Messerschmidia argentea (L.f.) I. M. Johnst.

Argusia argentea (L.f.) Heine

This seems merely to be a Tournefortia adapted to saline
strand habitats rather than related to Argusia.

Premna obtusifolia R. Br.
Premna integrifolia L.
Lycium carolinense var. sandwicense (A. Gray) Hitch.
Lycium sandwicense A. Gray
There seem to be almost no differences between the Central
Pacific strand Lycium and its relative on both coasts of sou-
thern North America.
Canthium barbatum f. calcicola Fosb.
Canthium odoratum (Forst.f.) Seem.
Guettarda speciosa L.
Ixora fragrans (H. and A.) A. Gray
Cephaelis fragrans H. and A.
Morinda umbellata var. forsteri (Seem.) Fosb.
Timonius polygama (Forst.) Robins.
Scaevola sericea var. tuamotuensis (St John) Fosb.

Bidens hendersonensis Sherff var. hendersonensis Sherff

Perhaps the only species of Bidens that reaches tree size.
Endemic to Henderson.

Bidens hendersonensis Sherff var. subspathulata Sherff
Endemic to Henderson, if indeed distinct from var. hendersonensis.
Fitchia nutans Hook.f,
Not found on Henderson since the original collection by Hugh
Cuming, which is suspected to have actually come from Tahiti.

The labels of some of Cuming's collections are known to have
been mixed.

Senecio stokesii F. Br.

Appendix 2. A revised list of the marine mollusks of Henderson Island
by Harald A. Rehder.

In 1913 a list of marine mollusks collected at Henderson Island was
published by E. A. Smith (1913). This collection was made by J. R.
Jamieson and D. R. Tait during their stay on the island while carrying
out a survey of the phosphate deposits. Before this list the only spe-
cies known from this island were those described by Broderip and Sowerby
from specimens collected here by Hugh Cuming and possibly also by Beechey.

In January 1971 I spent parts of two days on the island making col-
lections on the reef flat at the large beach on the north coast and also
on the adjoining cliffs.

In the following list those species collected by me and not appear-
ing in the 1913 paper by Smith are marked with an asterisk*. The names

in Smith's publication, when different, are cited under the presently
accepted name.

Haliotis pulcherrima Gmelin, 1791

Patelloida conoidalis (Pease, 1868)
Acmaea conoidalis Pease

Patella flexuosa Quoy and Gaimard, 1834
Patella stellaeformis Reeve, 1842

Broderipia iridescens (Broderip, 1834)

An examination of a large number of specimens of this genus

leads me to believe that Broderipia rosea (Broderip, 1834) and
B. subiridescens Pilsbry, 1890, represent growth stages of
iridescens.

Pseudostomatella (Stomatolina) speciosa (A. Adams, 1850)
Stomatella speciosa A. Adams

Cantharidus marmoreus (Pease, 1867)

Calliostoma roseopictum E. A, Smith, 1913

Turbo petholatus Linnaeus, 1758

Turbo argyrostomus Linnaeus, 1758

Nerita morio (Sowerby, 1833)
Nerita melanotragus Smith, 1884

In my Ducie report (Rehder and Randall, 1975, 29) I erroneously
reported this species as Nerita haneti Recluz, 1841.

Nerita plicata Linnaeus, 1758

Littorina coccinea (Gmelin, 1791)
Littorina obesa Sowerby, 1832
Nodilittorina pyramidalis pascua Rosewater, 1970
Littorina trochoides Gray, 1839
Royella sinon (Bayle, 1880)
Rhinoclavis sinensis (Gmelin, 1791)
Cerithium rubus Deshayes, 1843
Cerithium tuberculiferum Pease, 1869
Cerithium atromarginatum Bavay and Dautzenberg
Cerithium nassoide Sowerby, 1855
Cerithium egenum Ganildl, 1849
Cerithium rarimaculatum Sowerby, 1855

*Dendropoma maximum (Sowerby, 1825)

Epitonium torquatum (Fenaux, 1943)
Epitonium perplexum (Pease, 1868)

For a discussion of this identification see my report on the
marine mollusks of Easter Island (Rehder, 1980, 52).

Ianthina ianthina (Linnaeus, 1758)
Ianthina communis (Lamarck, 1822)
Vanikoro plicata (Recluz, 1844)
Strombus mutabilis Swainson, 1821
*Lambis truncata (Lightfoot, 1782)
*Lambis (Harpago) rugosa (Sowerby, 1842)
Polinices (Mamilla) simiae (Deshayes, 1838)
Mamilla simiae Deshayes
Natica gualteriana Recluz, 1844
Natica dillwyni Payraudeau, 1826

Cypraea cumingi Gray, 1832
Cypraea irrorata Gray, 1828

Cypraea goodalli Gray, 1832

Cypraea fimbriata Gmelin, 1791
Cypraea minoridens

Cypraea childreni Gray, 1825

Cypraea cicercula Linnaeus, 1758

Cypraea dillwyni Schilder, 1922
Cypraea margarita Gray, 1828, not Dillwyn, 1817

Cypraea helvola Linnaeus, 1758

Cypraea poraria Linnaeus, 1758

Cypraea caputserpentis Linnaeus, 1758
*Cypraea maculifera Schilder, 1932

Cypraea subteres Weinkauff, 1881
Cypraea scurra Gmelin, 1791
Cypraea isabella Linnaeus, 1758
*Cypraea mappa Linnaeus, 1758
Cypraea schilderorum (Iredale, 1939)
Cypraea arenosa Gray, 1824
*Cypraea ventriculus Lamarck, 1810
Trivia edgari Shaw, 1909
Trivia oryza Lamarck, 1810
Casmaria erinacea (Linnaeus, 1758)
Cassis (Casmaria) vibex (Linnaeus, 1758)
Morum ponderosum (Hanley, 1858)

Bursa (Colubrellina) granularis (Roding, 1798)
Bursa (Colubrellina) affinis (Broderip, 1833)

Maculotriton serrialis (Laborde, 1838)
Maculotriton bracteatus (Hinds, 1844) var.
Phyllocoma convoluta (Broderip, 1833)
Bursa (Craspedotriton) convoluta (Broderip)
Drupa morum Roding, 1798
Drupa horrida (Lamarck, 1816)
Drupa clathrata (Lamarck, 1816)
*Drupa elegans (Broderip and Sowerby, 1829)
Drupa ricinus (Linnaeus, 1758)

*Drupa (Drupina) grossularia Roding, 1798
Morula uva (Roding, 1798)

Drupa morus (Lamarck, 1822)
Morula granulata (Duclos, 1832)

Drupa tuberculata (Blainville, 1832) var.
Morula dealbata (Reeve, 1846)
Thais (Thalessa) intermedia (Kiener, 1835)

*Thais (Thalessa) affinis (Reeve, 1846)

Nassa sertum (Bruguiére, 1789)
Iopas sertum (Bruguiére)

Vexilla vexillum (Gmelin, 1791)
Vexillum vexillum (Chemnitz, 1788)
Vexillum taeniata (Powis, 1836)

Quoyula monodonta (Blainville, 1832)
Quoyula madreporarum (Sowerby, 1834)

Euplica palumbina (Gould, 1845)
Columbella turturina sensu Smith, 1913, not Lamarck, 1822

Euplica varians (Sowerby, 1832)
Columbella varians Sowerby

Pyrene obtusa (Sowerby, 1832)
Columbella obtusa Sowerby

Engina fuscolineata E. A. Smith, 1913

Engina rosacea (E. A. Smith, 1913)
Tritonidea rosacea E. A. Smith

Tritonidea difficilis E. A. Smith, 1913

Without an examination of the holotypes of the last two species
I am uncertain of their proper generic assignment.

Caducifer decapitata fuscomaculata (Pease, 1860)
Caducifer cylindrica (Pease, 1868)

Colubraria nitidula (Sowerby, 1833)

Alectrion papillosa (Linnaeus, 1758)
Nassa papillosa (Linnaeus)

Nassarius (Telasco) gaudiosa (Hinds, 1844)
Nassa gaudiosa Hinds

Latirus nodatus (Gmelin, 1791)

Mitra (Mitra) stictica (Link, 1807)
Mitra pontificalis Lamarck, 1811

Mitra (Mitra) coffea Schubert and Wagner, 1829
Mitra fulva Swainson, 1829

Mitra (Strigatella) auriculoides Reeve, 1845

Mitra (Strigatella) litterata Lamarck, 1811

Mitra maculosa Reeve, 1844

Vasum armatun (Broderip, 1833)

Neither I nor Jamieson and Tate found this species during our
visits to Henderson, although this is the type locality for the
species, described by Broderip from material collected by Cuming
in 1827. It is found from Rose Atoll, Eastern Samoa, and the
Ellice and Phoenix Islands, southeastward to Henderson Island.

Conus lividus Hwass, 1792
Conus ebraeus Linnaeus, 1758
Conus chaldeus Roding, 1798
Conus hebraeus var. vermiculatus Lamarck, 1810
Conus miliaris Hwass, 1792
Conus nanus Sowerby, 1833
Conus ceylonensis var. nanus Sowerby
*Conus sponsalis Hwass, 1792
Conus tessulatus Born, 1778

Conus tesselatus Born

Conus rattus Hwass, 1792
*Conus sanguinolentus Quoy and Gaimard, 1834
Conus retifer Menke, 1829

Conus solidus Sowerby, 1834
Conus tulipa Linnaeus, 1758
Conus tenuistriatus Sowerby, 1856

Conus glans var, tenuistriatus Sowerby
Conus pennaceus Born, 1778

Conus pennaceus var. episcopus Hwass 1792

Bulla species (juvenile)

Melampus flavus (Gmelin, 1791)
Melampus luteus Quoy and Gaimard, 1832
Arca avellana Lamarck, 1819

Arca maculata Sowerby, 1833

Acar divaricata (Sowerby, 1833)

Arca (Acar) domingensis sensu Smith, not Lamarck, 1819
Barbatia parva (Sowerby, 1833)

Arca (Barbatia) parva Sowerby
*Lima lima (Linnaeus, 1758)

Lima bullifera Deshayes, 1863

Spondylus species
Codakia (Epicodakia) bella (Conrad, 1837)

Lucina (Codakia) divergens Philippi, 1850
Tridacna maxima (Roding, 1798)

Tridacna crocea sensu Smith, not Lamarck, 1819

Tridacna squamosa sensu Smith, not Lamarck, 1819

Trapezium oblongum (Linnaeus, 1758)
Libitina guiniaca (Chemnitz 1784)

Chama asperella Lamarck, 1819
Chama jukesii Reeve, 1847

It is with some hesitancy that I assign the many valves that
I found on the beach to this species. Both Lamarck's species
and Chama spinosa Broderip, 1835, described from the Tuamotus,
and with which I had originally identified my specimens, have
white interiors. Most of my specimens are strongly tinged with
purple within, and Lamarck mentions a variety marked with purple
inside. Until a series of fresh, unworn specimens can be com-
pared with the types the proper identification of this species
will be in doubt. The true Chama jukesii Reeve from Australia
may be a related but distinct species.

Arcopagia (Scutarcopagia) scobinata (Linnaeus, 1758)

Tellina scobinata Linnaeus

Semele australis (Sowerby, 1832)

The known molluscan fauna, which is twice as large as that recorded
from Ducie, is typically Polynesian, and most of the species are those
commonly found in the Tuamotus, in which island group Henderson should
faunally be included, A few species, such as Nerita morio and Nodilitto-
rina pyramidalis pascua show an affinity with the Easter Island-Pitcairn-
Rapa subprovince.

Appendix 3. Resolution of the Pacific Science Association adopted at
the XV Pacific Science Congress. Feb. 1-11, 1983. Dunedin, New Zealand.

Henderson Island

WHEREAS, elevated coral islands are few in number and of great biologi-
cal and geological interests; and

WHEREAS, most such islands have been drastically altered by man through
commercial exploitation; and

WHEREAS, Henderson Island, in the Pitcairn Group, is a raised coral
island of twelve square miles, uninhabited and untouched except for
occasional visits by inhabitants of Pitcairn, 100 miles distant, to
obtain wood of the miro trees growing at the margin of the wooded in-
terior of the island; and

WHEREAS, Henderson Island is the only habitat of a number of endemic
species of angiosperm plants, birds, land snails, and insects, dis-
covered during very limited surveys of the island; and

WHEREAS, Henderson Island, because of its being a raised coral island
with narrow fringing reefs, narrow sandy beaches, and steep coral
cliffs, has a marine environment unique to that part of eastern Poly-
nesia; and

WHEREAS, preliminary investigations on the island have revealed the
presence of important archaeological sites, suggesting early occupation
by the Polynesians; and

WHEREAS, a private individual is seeking permission to live on Henderson
Island and to build a house, a jet airstrip, and loading facilities for
ships;

BE IT RESOLVED that the Pacific Science Association urges the British
Government not to permit the proposed development before: (1) a detailed
biological survey of the island has been carried out, in which the par-
ticipation of responsible scientific agencies should be encouraged;

(2) the likely ecological effects of the proposed development have been
assessed; and (3) the views of Pitcairn Islanders on the proposed de-
velopment have been obtained.

NOTE ON HENDERSON ISLAND RESOLUTION

On March 1, 1983, in the House of Lords, Lord Melchett asked Her Majesty's
Government a number of questions on the proposed occupancy of Henderson
Island, including whether they agree with the view expressed in the Inter-
national Biological Programme's Report in 1968 that Henderson Island
should be preserved as an "island for science."

Pacific Science Association Information Bulletin 35 (1-2): 17, 18-19,
April 1983.

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Bank, J. 1909. Extract from a report from Mr James Bank to Consul
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islands in its vicinity. Hydrographic Department, Ministry of
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Beck, R. H. 1923. The voyage of the France. Nat. Hist. 23: 33-34.

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Bellon, H. 1974. Histoire géochronologique des fles Gambier. Cah.
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Beltran y Roéspide, R. 1884. Las Islas Tahiti: Descubrimiento. La
Polinesia (Madrid), 143-151.

Berland, L. 1942. Polynesian spiders. Occ. Pap. Bernice P. Bishop
Mus. 17: 1-24.

Bourne, W. R. P. and David, A. C. F., in prep. Henderson Island, Central
South Pacific, and its birds. Manuscript.

Brodie, W. 1851. Pitcairn's Island, and the islanders in 1850. London:
Whittaker and Co. 260 pp.

Brousse, R., Philippet, J. C., Guille, G. and Bellon, H. 1972. Géochrono-
métrie des Iles Gambier (Océan Pacifique). C. R. hebd. Séanc. Acad.
sci., Paris 274: 1995-1998.

eee Eee EEE ee ee ee —————

* Items marked * are cited with permission of Lt Cdr A. C. F. David.

Brown, E. D. W. and Brown, F. B. H. 1931. Flora of southeastern
Polynesia. II. Pteridophytes. Bull. Bernice P. Bishop Mus.
89: 1-123.

Brown, F. B. H. 1931. Flora of southeastern Polynesia. I. Monocoty-
ledons. Bull. Bernice P. Bishop Mus. 84: 1-194.

Brown, F. B. H. 1935. Flora of southeastern Polynesia. III. Dicotyledons.
Bull. Bernice P. Bishop Mus. 130: 1-386.

Caillet, X. 1884. Iles découvertes par Pedro Fernandez de Quirés du
s

21 décembre 1605 au 2 mars 1606, dans sa traversée de Callao a 1'fle
Gente Hermosa. J. off. Etabl. Frang. Océanie, 33: 135-138.

Chappel, T. 1830. An account of the loss of the Essex from having been
struck by a whale in the South Seas, with some interesting particu-
lars of the sufferings of her crew on a desert island and in their
boats at sea. London: Religious Tract Society.

Chase, 0. 1821. Narrative of the most extraordinary and distressing
shipwreck of the whale-ship Essex of Nantucket, which was attacked
and finally destroyed by a large spermaceti-whale in the Pacific
Ocean, with an account of the unparalleled sufferings of the cap-
tain and crew during a space of ninety-three days in open boats,
in the years 1819 and 1820. New York: W. B. Gilley. 128 pp.

Cooke, C. M., Jr. 1935 see Gregory, H,E. 1935,

Cooke, C. M., Jr. and Kondo, Y. 1960. Revision of Tornatellinidae and
Achatinellidae (Gastropoda, Pulmonata). Bull. Bernice P. Bishop
Mus. 221: 1-303.

Copeland, E. B. 1938. Ferns of southeastern Polynesia. Occ. Pap.
Bernice P. Bishop Mus. 14(5): 45-101.

Distant, W. L. 1913. On a small collection of Rhynchota made by Mr
David R. Tait at Henderson's Island. Ann. Mag. Nat. Hist., ser.
8, vol. 11: 554-557.

Douglas, G. 1969. Draft check list of Pacific oceanic islands, Micro-
nesica, 5: 327-463.

Drew, R. A. I. 1975. Zoogeography of Dacini (Diptera: Tephritidae) in
the south Pacific area. Pacific Insects. 16: 441-454.

Dunean, R. A., McDougall, I1., Carter, R. M. and Coombs, Di Sy 1974
Pitcairn Island - another Pacific hot spot? Nature, Lond. 251:
679-682.

du Pont, J. E. 1976. South Pacific Birds. Delaware Mus. Nat. Hist.
Monogr. Ser. 3: i-xii, 1-218, illus.

Fennah, R. G. 1958. Fulgoroidea of south-eastern Polynesia. Trans.
R. ent. Soc. 110: 117-220.

Fosberg, F. R. 1937. Some Rubiaceae of southeastern Polynesia. Occ.
Pap. Bernice P. Bishop Mus. 13(19): 245-293.

Gibbings, R., ed. 1935. Narratives of the wreck of the whale-ship Essex
of Nantucket which was destroyed by a whale in the Pacific Ocean in
the year 1819, told by Owen Chase First Mate, Thomas Chappel Second
Mate and George Pollard Captain of the said vessel, together with an
introduction and twelve engravings on wood by Robert Gibbings.
London: Golden Cockerel Press. 88 pp.

Gough, B. M., ed. 1973. To the Pacific and Arctic with Beechey: the
journal of Lieutenant George Peard of H.M.S. 'Blossom', 1825-1828.
Cambridge: Hakluyt Society (ser. 2), 143: x, 272 pp.

Grant, C. H. B. and Mackworth-Praed, C. W. 1933. Sula nicolli, sp. nov.,
White-tailed Red-footed Booby. Bull. Br. Orn. Club. 53: 118-119.

Gregory, H. E. 1935. Mangarevan Expedition. Bishop Mus. Bull. 133:
33-71.
Contains reports by C. M. Cooke, Jr., H. St John, P. H. Buck, K. P.
Emory, J. F. Stimson and E. C. Zimmerman, the first two and the
last with information on Henderson Island.

Grindle, G. 1920. Letter dated 3 December 1920. Hydrographic Depart-
ment, Ministry of Defence, archives, M65489/20.%*

Hamilton, K. G. A. 1980. Aphrophorinae of Polynesia (Rhynchota: Hem-
optera: Cercopidae). Pacific Insects. 22: 347-360.

Heffernan, T. F. 1981. Stove by a whale: Owen Chase and the Essex.
Middletown, Conn.: Wesleyan University Press.

Heimerl, A. 1937. Nyctaginaceae of southeastern Polynesia and other
Pacific islands. Occ. Pap. Bernice P. Bishop Mus. 13(4): 27-47.

Hemsley, W. B. 1885. Botany, Report on the scientific results of the
voyage of H.M.S. Challenger. 1(1): i-xii, 1-75.

Hooker, W. J. and Arnott, G. A. W. 1841, The botany of Captain Beechey's
voyage; comprising an account of the plants collected by Messrs Lay
and Collie ... in the years 1825, 26, 27, and 28. London: H., G.
Bohn. 485 pp.

Hutchinson, G. E. 1950. Survey of contemporary knowledge of biogeo-
chemistry. 3. The biogeochemistry of vertebrate excretion. Bull.
Am. Mus. Nat. Hist. 96: i-xviii, 1-554.

Jackson, H. G. 1938. Terrestrial isopods of southeastern Polynesia.
Occ. Pap. Bernice P. Bishop Mus. 14(10): 167-192,

Kelly, C., ed. 1966. La Austrialia de Espiritu Santo. The journal of
Fray Martin de Munilla O.F.M. and other documents relating to the
voyage of Pedro Fernandez de Quirés to the South Sea (1605-1606)
and the Franciscan missionary plan (1617-1627). Cambridge: Hakluyt
Society (ser. 2), 126. WVoll.-d! i-xviia; 1-270; Voll. 22 i-xvaneaale
446.

King, H. 1820. Extract from the journal of Captain Henry King of the
Elizabeth. Edinb. phil. J. 3: 380-388,

King, W. B. 1967. Preliminary Smithsonian identification manual: sea-
birds of the tropical Pacific Ocean. Washington: Smithsonian
Institution. 126 pp.

Kondo, Y. 1962. The genus Tubuaia: Pulmonata, Achatinellidae. Bull.
Bernice P. Bishop Mus. 224: 1-49.

Labeyrie, J., Lalou, C. and Delibrias, G. 1969. Etude des transgressions
marines sur l'atoll de Mururoa par la datation des différents niveaux
de corail. (Cah. Pacifie 132 205-212"

Lam, H. J. with Meeuse, B. J. D. 1938. Monograph of the genus Nesoluma
(Sapotaceae), a primitive Polynesian endemic of supposed Antarctic
origin. Occ. Pap. Bernice P. Bishop Mus. 14: 127-165.

Lucas, C. P., ed. 1929. The Pitcairn Island register book. London: Society for
the Propagation of Christian Knowledge. iii, 181 pp.

Maiden, J. H. 1901. Notes on the botany of Pitcairn Island. Rept.
Australas. Ass. Adv. Sci. 8: 262-271.

Malloch, J. R. 1938. Trypetidae of the Mangarevan Expedition (Diptera).
Occ. Pap. Bernice P. Bishop Mus. 14(7): 111-116.

Markham, C. R., ed. 1904. The voyage of Pedro Fernandez de Quirés, 1595
to 1606. London: Hakluyt Society (ser. 2) 15. Vol. 1: i-xlviii,
1-320; Vol. 2: i-viii, 321-555.

Maude, H. E. 1951. Those Henderson Island mysteries. Pacif. Is. Mon.
21(10): 62-63.

Maude, H. E. 1959. Spanish discoveries in the Central Pacific: a study
in identification. J. Polynes. Soc. 68: 284-326. Reprinted in
Of islands and men: Studies in Pacific history (Melbourne: Oxford
University Press, 1968), 35-83.

McLoughlin, R, 1971. Law and order on Pitcairn Island. Auckland:
Office of the Governor of Pitcairn, Henderson, Ducie and Oeno Islands.

McNutt, M. and Menard, H. W. 1978. Lithospheric flexure and uplifted
atolls. J. geophys. Res. 83: 1206-1212.

Meinicke, C. E. 1875-76. Die Inseln des Stillen Oceans: eine geogra-
phische Monographie. Leipzig: Frohberg. 2 vols.

Moerenhout, J.-A. 1837. Voyage aux files du Grand Océan. Paris. 2 vols.

Moulton, D. 1939. Thysanoptera collected by the Mangarevan Expedition.
Occ. Pap. Bernice P. Bishop Mus. 15: 141-148.

Murphy, R. C. 1924a. The Whitney South Sea Expedition: a sketch of
the bird life of Polynesia. Natural History, 24: 539-553.

Murphy, R. C. 1924b. Birds collected during the Whitney South Sea Ex-
pedition, II. Am. Mus. Novit. 124: 1-13.

Murphy, R. C. 1951. The populations of the wedge-tailed shearwater
(Puffinus pacificus). Am. Mus. Novit. 1512: 1-21.

Murphy, R. C. and Mathews, G. M. 1929. Birds collected during the
Whitney South Sea Expedition, VI. Am. Mus. Novit. 350: 1-21.

Murphy, R. C. and Pennoyer, J. M. 1952. Larger petrels of the genus
Pterodroma. Am. Mus. Novit. 1580: 1-43.

Murray, T. B. 1854. Pitcairn: the island, the people, and the pastor;

with a short account of the mutiny of the Bounty. Third edition.
London: Society for the Propagation of Christian Knowledge. xiv,
342 pp.

Naval Intelligence Division. 1943. Pacific Islands, Volume II. Eastern
Pacific. Geographical Handbooks Series, B.R. 519B: xvi, 739 pp.

North, A. J. 1908. On three apparently undescribed birds from Hender-
son or Elizabeth Island, Paumotu Group. Rec. Austr. Mus. 7: 29-32.

Ogilvie-Grant, W. R. 1913a. On a small collection of birds from Hender-
son Island, South Pacific, collected and presented to the British
Museum by Messrs D. R. Tait and J. R. Jamieson. Bull. Br. Orn. Cl.
31: 58-61.

Ogilvie-Grant, W. R. 1913b. On a small collection of birds from Hender-
son Island, South Pacific. Ibis, (10) 1: 343-350.

Ortenburger, A. I. 1923. Herpetological results of the Whitney South
Sea Expedition. III. Further notes on the reptiles collected by
the Whitney South Sea Expedition. Copeia, 107: 59-60.

Peters, J. L. 1934. Check-list of birds of the world. Cambridge:
Harvard University Press. Vol. 2.

Quayle, E. H. 1922. Extract from the Journal ... Whitney South Sea
Expedition. Manuscript in the Bird Division of the American
Museum of Natural History,

Rehder, Harald A. 1980. The marine mollusks of Easter Island (Isla de
Pascua) and Sala y Gomez. Smithsonian Contributions to Zoology,
No. 289: iv + 167 pp., 14 plates, 15 text figures, 1 table.

Rehder, H. A. and Randall, J. E. 1975. Ducie Atoll: its) history,
physiography and biota. Atoll Res. Bull. 183: 1-40.

Ripley, S. D. 1977. Rails of the world: A monograph of the family
Rallidae. With forty-one paintings by J. Fenwick Lansdowne and a
chapter on fossil species by Storrs L. Olson. Toronto: M. F.
Feheley Publishers. xx, 406 pp.

Ripley, S. D. and Birckhead, H. 1942. Birds of the Whitney South Sea
Expedition. 51. On the fruit pigeons of the Ptilinopus purpuratus
group. Am. Mus. Novit. 1192: 1-14.

Rivett-Carnac, J. R. 1937. Report on aerial and ground survey of
Henderson, Oeno and Ducie Islands. Western Pacific Archives,
Western Pacific High Commission (South Pacific Office), File No.
3326/1937 (Naval). [Not seen].

St John, H- 1935. See Gregory, H. B= «1935.

St John, H. 1940. Itinerary of Hugh Cuming in Polynesia. Occ. Pap.
Bernice P. Bishop Mus. 16: 81-90.

St John, Harold & Philipson, W. R. 1962. An account of the flora of
Henderson Island, South Pacific Ocean, Trans. R. Soc. N. Z.
1: 175-194.

Sharp, A. 1960. The discovery of the Pacific islands. Oxford:
Clarendon Press. xvi, 260 pp.

Sherff, E. E. 1937. Some Compositae of southeastern Polynesia (Bidens,

Coreopsis, Cosmos, and Oparanthus). Occ. Pap. Bernice P. Bishop
Mus. 12(19): 1-19.

Sinoto, Y. H., [in press]. Analysis of Polynesian migrations based on
archaeological assessments. J. Soc. Océanistes, Paris.

Skottsberg, C. 1937. Liliaceae of southeastern Polynesia. Occ. Pap.
Bernice P. Bishop Mus. 13(18): 233-244.

Skottsberg, C. 1938. Ericaceae and Santalaceae of southeastern Poly-
nesia. Occ. Pap. Bernice P. Bishop Mus. 14(4): 31-43.

Smith, E. A. 1913. On a small collection of marine shells from Hender-
son Island. Ann. Mag. Nat. Hist. (8) 12: 409-415.

Solem, G. A. 1976. Endodontoid land snails from Pacific Islands.
Part I. Family Endodontidae. Field Museum Press. 501 pp.

Tait, D. R. 1912. Letter to Sir John Murray, 20 January 1913. Hydro-
graphic Department, Ministry of Defence, archives. H5364/20.*

Tate, G. H. H. 1935. Rodents of the genera Rattus and Mus from the
Pacific islands, collected by the Whitney South Sea Expedition,
with a discussion of the origin and races of the Pacific Island
Rat. Bull. Am. Mus. Nat. Hist. 68: 145-178.

Van Dyke, E. C. 1937. Rhyncogonus of the Mangarevan Expedition. Occ.
Pap. Bernice P, Bishop Mus. 13(11): 89-129.

Von Poellnitz, K. 1936. New species of Portulaca from southeastern
Polynesia. Occ. Pap. Bernice P. Bishop Mus. 12(9): 1-6.

Wheeler, W. M. 1936. Ants from the Society, Austral, Tuamotu, and
Mangareva Islands. Occ. Pap. Bernice P. Bishop Mus. 12(18): 1-17.

Williams, G. R. 1960. The birds of the Pitcairn Islands, certral
Pacific Ocean. Ibis, 102: 58-70.

Yuncker, T. G. 1937. Revision of the Polynesian species of Peperomia,
Bull. Bernice P. Bishop Mus. 143: 1-73.

Zimmerman, E. C. 1935. See Gregory, H. E. 1935.

Zimmerman, E. C. 1936. Cryptorrhynchinae of Henderson, Pitcairn, and
Mangareva Islands (Coleoptera, Curculionidae). Occ. Pap. Bernice
P. Bishop Mus. 12(20): 1-8.

Zimmerman, E. C. 1938. Anthribidae of southeastern Polynesia (Coleop-
tera). Occ. Pap. Bernice P. Bishop Mus. 14(13): 219-250.

North coast with low cliffs, beach,and coconut and other vegetation
back of beach, from sea (Rehder photo).

North coast, from sea, closer up. Pitcairn people on beach preparing
to load coconuts and Thespesia wood (Rehder photo).

Plate 3. Base of cliff on north coast showing small cave site of archaeological
excavation by Dr. Sinoto (Rehder photo).

4. West coast, undercut cliffs (Rehder photo).

Plate 5. West coast, looking north from near south end, from top of cliff
(1943 photo).

6. West coast, looking north, near northwest point, from part way up cliff
(Fosberg photo).

Plate 7. Cliffs back of North Beach, back-beach scrub in foreground, single
coconut tree on top of cliff (1943 photo).

8. Vegetation of interior plateau, from top of large Pandanus tree
(Fosberg photo).

aez” Su
(3 co a2

. we a .z « — .
“ - Sal . |
0)" APACE.
ee) .
A ue i 4 ae * - ~ ma
Plate 9. Interior of back-beach vegetation, north coast, showing Pandanus
(Rehder photo).

10. Tangled interior of vegetation (1943 photo).

Plate 11. Dissected limestone on plateau, forest in background (Fosberg photo).

12. Dissected limestone. on plateau, close-up, surrounded by forest
(Fosberg photo).

* U.S. GOVERNMENT PRINTING OFFICE : 1983 O - 413-333

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z =2T) >, 5 =z a 2 —)
IBRARI ES. SMITHSONIAN, INSTITUTION NOILMLILSNI_NVINOSHLIWS S31yvudlT_ LIBRARIES SMITHSONIAN |
A
° = S) = Ne S) wo ‘S) wo
= gh Mg Ki a (S 2 Ws: = g = =
2 uy > =) zy 4 NS a >) 5
Ew YZ = > NSN = > E s >
5 if 2 i 2 = 2 i 2
2 a Z a Z a Z i
NOILNALILSNI NVINOSHLINS S3IYVYEIT_ LIBRARIES SMITHSONIAN INSTITUTION NOILNLILSNI iS
zZ a Z Ron Y Zz Ne i) Zz )
.& = y x = < OX = as =
Zz 4 ysl fy = Si best Zz AS = Zz Sj
tip f () : oP oN
= 2 Viy = z = WS 2 i 2
= 5 F . 3 a = z =
IBRARIES SMITHSONIAN _ INSTITUTION NOILOLILSNI_NVINOSHLIWS LIBRARIES SMITHSONIAN 1
n S = an p) = 7) =
EE, Foo a o & o uw ae
= i jp 2 a 2 Qk = a =
“Gif c = c BW = c << c
oc “Shy a a
Vy = = aN = =i
Ee: : ae : : :
| E A
OILALILSNI_NVINOSHLINS S3IYVYGIT LIBRARIES SMITHSONIAN INSTITUTION NOILONLILSNI S
= * S x FS : us z im Zz
ios] > — wo = fp jes} = w —
= Ne 5 : = G% > E = E
a Ye S 2 if : 5 2
2 XA E 2 = fe 2 = 2 =
al SS NS oP) = it te oO = oD) = wo
no ms = wn z n = 7) z
IBRARIES SMITHSONIAN INSTITUTION NOILALILSNI NVINOSHLINS S31uvugia_ LIBRARIES SMITHSONIAN II
no Za Xe ) z n Ze ie on Fe
= ee = 5 = ely s Es
: 2\, i B,3 : : : :
a a NS b fff @ w 2) a a
fe) rT WAN SG GY YY, fe) 36 (e) Ts
Z E \ 2.4 E Z = = E
= = WN > = > = > =
2 77 ie z oO Zz 7) 2 7)
_NWVINOSHLINS S3IYVYAIT LIBRARIES SMITHSONIAN INSTITUTION _NVINOSHLIWS S
z 4 Ss ¢p) > n > i We
a ES oe es % = “i 4
= cc 2 oc = a = AW ce
a <= Z < Se < 2 YN <
= oO el = =I mi =I RN NS oO
S) = o =a rs) a One Poss =
2 ay ze = 7 =i 2 =
IBRARIES SMITHSONIAN INSTITUTION NOILMLILSNI NVINOSHLINS S3!uYvusit LIBRARIES SMITHSONIAN I
= 3 eo Sas = ie Re z S z a
i ZESON Dy ~ <o aS 14 oO RSV = <a ie) <IUSV wo ASMSONT >» Y Paice
ED) 5 gi zy 2 EPR 5 PD 2 SK EGPDIG™S wy?
AS) FS) SeZZe > te Wel - (z 4) > Ws rans | 2 la Sel] Se >

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