Five-year Status Reviews
of Sea Turtles Listed Under
the Endangered Species
Act of 1 973

January 1985

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U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration

S^H^ National Marine Fisheries Service

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in 2012 with funding from

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http://www.archive.org/details/fiveyearstatusreOOmage

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Five-year Status Reviews of
Sea Turtles Listed Under
the Endangered Species
Act of 1 973

Prepared by Andreas Mager, Jr.
National Marine Fisheries Service
Protected Species Management Branch
Duval Building, 9450 Kroger Boulevard
St. Petersburg, Florida 33702

January 1985

■

r

U.S. DEPARTMENT OF COMMERCE

Malcolm Baldrige, Secretary

National Oceanic and Atmospheric Administration

Anthony J. Calio, Acting Administrator

National Marine Fisheries Service

William G. Gordon, Assistant Administrator for Fisheries
Jack T. Brawner, Southeast Regional Director

CONTENTS

Introduction 1

Acknowledgements 3

STATUS REVIEWS

Green Sea Turtle 4

Hawksbill Sea Turtle 21

Loggerhead Sea Turtle 35

Kemp's Ridley Sea Turtle , 46

Olive Ridley Sea Turtle 56

Leatherback Sea Turtle 70

Literature Cited 82

i i

INTRODUCTION

Section 4 of the Endangered Species Act requires the
National Marine Fisheries Service (NMFS), an agency of the
Department of Commerce, and the Fish and Wildlife Service
(FWS), an agency of the Department of the Interior, to review
the status of listed species at least once every five
years. The Services use these status reviews to determine
whether a designation as threatened or endangered accurately
reflects the current status of a listed species. If the
status of the species has either improved or deteriorated,
appropriate action will be taken to ensure that the species
is listed accurately.

Information published between 1978 and 1984 is
summarized in this review by NMFS, and an assessment is made
of the current status of the populations of sea turtles that
are listed pursuant to the Endangered Species Act of 1973
(ESA). The leatherback sea turtle (Dermochelys coriacea) and
hawksbill sea turtle ( Ere tmochelys imbricat a ) were listed as
endangered throughout their range on June 2, 1970. The
population of Kemp's ridley ( Lep idochelys kempi) was listed
as endangered on December 2, 1970. The green sea turtle
(Chelonia mydas) was listed on July 28, 1978, as threatened
except for the breeding populations of Florida and the
Pacific coast of Mexico which are listed as endangered. At
the same time, the olive ridley ( Lepidochelys olivacea) was
listed as threatened, except for the breeding populations of
the Pacific coast of Mexico which are listed as endangered.
On July 28, 1978, the loggerhead sea turtle (Caretta caretta)
was listed as threatened wherever it occurs. These sea
turtles were listed because, to varying degrees, their
populations had declined as the result of human activities.
Many of their nesting beaches had been destroyed by
encroachment of the human population into coastal habitats.
Sea turtle populations had been reduced by uncontrolled
harvesting for commercial purposes and by mortality
incidental to activities such as commercial fishing. In many

ij. 5.

cases, existing regulatory mechanisms were not providing
sufficient encouragement for conservation.

To prepare this document, the National Marine Fisheries
Service reviewed a considerable amount of literature
published between 1978 and 1984. However, our knowledge of
the status of the various sea turtle populations has
increased very little since 1978.

Descriptions of the status of all sea turtle populations
in the Atlantic, Pacific, and Indian Oceans are presented by
species. The terms population and stock are generally used
to define a group of sea turtles nesting within the
boundaries of a given political entity rather than biological
stocks. The breeding biology and taxonomy of most sea turtle
stocks have not been sufficiently investigated to define
distinct breeding populations or stocks. Tagging studies
demonstrate that green, olive ridley, Kemp's ridley, and
loggerhead sea turtles return to their natal beaches to breed
and nest. If breeding is restricted to near these nesting
beaches and male sea turtles return with the females, then a
mechanism for genetic isolation exists and each nesting
population could be considered a distinct stock for
management purposes. Leatherback sea turtles are not such
strict remigrators and may change nesting beaches. The
breeding biology and migration patterns of hawksbill turtles
are not well documented, largely because of the diffuse
nesting habitats of other species. Consequently, mechanisms
for stock di f f erenta t ion may be different or nonexistent for
leatherback and hawksbill sea turtles. Until a thorough
systematic study is completed to define biological stocks,
the Services will continue to divide populations of sea
turtles along political boundaries.

The ESA requires the consideration of five factors in
determining whether a population, stock, or higher taxon
qualifies for listing on either the threatened or endangered
species lists. This review re-evaluates these factors to
determine if information developed over the last five years
continues to support the designation of each sea turtle
population as threatened or endangered. The Assistant
Administrator for Fisheries has agreed with the conclusions
and recommendations reached in this report that no changes
should be made concerning the listing of sea turtles except
to list the nesting populations of olive ridleys as
endangered rather than threatened in the Western North
Atlantic (Surinam and adjacent areas).

ACKNOWLEDGEMENTS

This opportunity is taken to thank the many people
involved in providing information and constructive comments
on the status reviews. Specific thanks go to George Balazs,
Dr. Kenneth Dodd, Dr. Charles Karnella, James Lecky,
William N. Lindall, Margaret Lorenz, Gene Nitta, Larry Ogren,
Charles A. Oravetz, Dr. Peter Pritchard, Dr. Nancy Thompson,
and Wayne Witzell. Secretarial assistance was provided by
Carol B. Fowler, Cecelia Quinn, and Brenda MCCloud.

GREEN SEA TURTLE

C€h«lonl« nytful

Green Sea Turtle
( Chelonia my das )

Biological Background

Although there is insufficient taxonomic information to
distinguish between stocks, there may be geographically and
genetically distinct populations of the green sea turtle.
Replacement of extinct populations by transplanting
individuals from another population has not succeeded, and,
even if it were to succeed, the animals would be biologically
different (Ehrenfeld 1982). Although the treatment of the
species as a single stock may be ill-advised, because of its
worldwide distribution, the lack of data indicating discrete
stocks, and the difficulties in distinguishing separate
stocks, populations and subspecies, the species is
necessarily considered a single stock in the Indo-Pacific
region and a single stock in the Atlantic Ocean and adjacent
seas for puposes of this review.

In various parts of its range, the green sea turtle also
may be called tortuga verde, greenback turtle, edible turtle,
soup turtle, tortue verte, tortuga blanca, tartaruga verde,
aruana and krape (Pritchard et al. , 1983). It is
distinguishable from other sea turtles by its four large
plates on each side of its upper shell and one pair of
prefrontal scales (scales found on the head between the nasal
opening and eye socket); shell plates that do not overlap;
and paddle shaped limbs that normally have only one claw
(Carr, 1952). The color of the shell in most adult green sea
turtles is highly variable, but background color may be light
to dark brown, green, buff, black, or olive (Pritchard,
1979). The underside is usually white to pale yellow
(Pritchard, 1979).

Size, weight, and shell shape probably vary between
turtles from different parts of the world. Using Hirth's

(1971) classifications, hatchlings are identified by
conspicuous umbilical scars; juveniles by a carapace length
up to 16 inches; sub-adults by a length of 16 to 32 inches;
and adults by a length greater than 32 inches. The typical
adult has an average shell length of about 40 inches and
weighs between 300-350 pounds ( Groombr idge , 1982). Very
large individuals have been observed with shell lengths of
over five feet and weights of 850 pounds (Rebel, 1974).
There is no sexual-dimorphism in subadult male or female
turtles; however, adult males have long tails that reach well
beyond the rear edge of the shell, while adult females have
shorter tails that barely reach beyond the rear edge (Hirth,
1971). Green sea turtles are believed to be long lived (20
years or longer), but longevity in the wild is unknown
(Hirth, 1971). Estimates of age at sexual maturity range
from 4 to 59 years depending on the locale (Hirth, 1971;
Balazs, 1980; Owens, 1980). Length at sexual maturity is
about 35 inches.

Green sea turtles are primarily herbivores that eat sea
grasses and algae. Other organisms living on sea grass
blades and algae add to the diet. Predators of adult turtles
include man, killer whales, and sharks (Bacon et al. ,
1984). Eggs are eaten by man, raccoons, coatimundi, dogs,
pigs, foxes, peccary, lizards, rats, crabs, and birds (Hirth,
1971). Hatchlings are eaten by dogs, hogs, rats, mongoose,
cats, lizards, snakes, jackfish, kingfish, snook, barracuda,
groupers, rock cod, and sharks (Hirth, 1971). The loss of
eggs and hatchings to predation is assumed to be very high.
Only one to three percent of the hatchlings reach sexual
maturity and only about 50 percent of the eggs hatch (Hirth,
1971).

Shallow water areas such as shoals and lagoons vegetated
with sea grasses and algae are preferred habitat. Inlets,
bays, and estuaries containing abundant submerged vegetation
are also used. Green sea turtles nest in all subtropical to
tropical oceans of the world within 35° north and south
latitude (Figure 1) in waters that remain above 20°C in the
coldest months (Rebel, 19 74; Groombr idge, 19 82).

In the Atlantic Ocean and adjacent seas, they roam from
Massachusetts southward to Florida and throughout the Gulf of
Mexico and the Caribbean Sea (Rebel, 1974). They occur off
Mexico and off South America to the Argentine coast at Mar de
la Plata and Necochea (Carr, 1952). The green sea turtle
rarely is encountered in European Atlantic waters
(Brongersma, 1982). Only two specimens are reported; one

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from Petten, the Netherlands and one from the Ria de Arosa,
northwest Spain. In Macaronesian waters, it is known from
only a few records from the Azores and in Madeira. In west
African waters, it is reported from Morocco, Mauritania, Cape
Verde Islands, Senegal, Sierra Leone, Liberia, Ghana, Togo,
Fernando Poo, Sao Thome, Ilha do Principe, Congo, Zaire,
Angola, Bahia dos Tigres, southwest Africa, Sal Island,
Boavista Island, Maio Island, Fogo Island, and Sao Tiago
Island (Brongersma, 1982). They also occur in the
Mediterranean and Aegean Seas (Sella, 1982; Geldiay et al.,
1982).

Green sea turtles are also widely distributed in the
Pacific and Indian Oceans. Along the eastern Pacific,
records are available from British Columbia to Chiloe,
Chile. They are distributed throughout the Central Pacific
and Indian Ocean, and, in the western Pacific, are found from
Japan, China, and Kaia in the north to the Kermadec Islands
and New Zealand in the south.

The nesting season varies with location. Nesting is
reported between May and August at the Yucatan Peninsula;
between April and August in the West Indies; from September
to January off the coast of West Africa; between July and
September at Senegal; November to February at Fernando Poo
(Hirth, 1971), and between May and November in Florida.
Nesting was observed between May and September in the
Mediterranean Sea (Geldi ay et at . , 1982). In the Pacific and
Indian Ocean, nesting has been reported between July and
December in Chiapas, Mexico; December to March at the
Galapagos Islands; August and September at Rose Atoll;
October to December at French Polynesia; November to February
at the Tonga Islands; December and January at New Caledonia;
February to August at Mazivi Island, Tanzania; January to
March at the Seychelles Islands; June and July at Jurayd
Island in the Persian Gulf; and in June at Masira Island,
Oman (Hirth, 1971).

Most females nesting on a given beach are never seen
again (Hughes, 1981). The ones that do return to nest do not
return at a universal interval; however, returns to nest have
been observed in two, three, or four year cycles (Carr et
al. , 1978). The females deposit between three and seven
clutches per season at about 10 to 18 day intervals. Average
clutch sizes vary between 81 and 147 eggs that hatch usually
within 48-72 days (Hirth, 1971; Groombridge, 1982).
Hatchlings emerge, mostly at night, travel quickly to the
water, and swim out to sea in what is called a "swimming

frenzy". At this point, they enter their "lost year" period
before they begin diving behavior. This period may be spent
in areas where currents concentrate debris and floating
vegetation such as sargassum (Groombr idge , 1982).

Since the breeding and nesting grounds are often
separated by long distances from the foraging area, long
distance migrations are required between these sites.

Population Size

Table 1 includes the information available on the green
sea turtle. This information is obtained mainly from Bacon
(1981), Balazs (1982), Bjorndal (1982), Carr et _d. (1982),
Groombr idge (1982), Bacon et al. (1984) and others.

The number of green sea turtles that existed before
commercial exploitation and the total number that now exists
are not known. Therefore, information on the decline of
these turtles is based on nesting females (since sex ratios
have not yet been determined, the number of males that exists
cannot be determined). The decline and elimination of many
nesting beaches and the less frequent encounters with green
turtles in the wild provide inferential evidence that stocks
are generally declining.

Although the species probably has always been an
important source of protein for coastal dwellers, the
commercial exploitation during the 16th and 18th centuries
decimated the stocks. Lund (1973) estimated that the
Caribbean stocks during the era of Spanish exploration may
have been 50 million turtles. By the 1940's, the commercial
demand for green sea turtles dropped to a minimum based on
declines of wild populations. However, renewed interest and
exploitation which began soon after was based on the demand
for gourmet foods, cosmetics, leather, flesh, calipee, oil
and skin. This renewed exploitation was curbed in the
United States when the species was listed pursuant to the
Endangered Species Act. Ehrenfeld (1974) later estimated
that the world population of sexually mature green sea
turtles in the 1970s number only between 100,000 and 400,000
males and females. Greater detail on the status of the
stocks prior to this review can be found in the Final
Environmental Impact Statement on Listing and Protecting the
Green Sea Turtle (Anonymous, 1978).

Table 1. Population information, population trends and

exploitation of the green sea turtle (Chelonia mydas)

ATLANTIC OCEAN AND ADJACENT SEAS

Location

Population Information

Trend 2/

Exploitation

Angola

613 F 3/ (197*) 4/

U

Antigua

39 F 71982)

U

150 turtlea/year

Ascension I.

1,000 - 2,000 F/year

S

Bahama

+

D

11,090 pounds (1980-82)

Belize

19 F (1982)

U

Brazil

3,000 - 10,000 F/year

U

8,399 pounds/year

British Virgin la.

75 F (1981)

U

100 turtlea/year

Cape Verde la.

+

D

Caymen Islands

+

D

170 turtles/year

Colombia

+

D

Costa Rica

4,392 F (1981)

U

237,571 pounds (1980-82)

Cuba

+

D

329 turtles/year

Dominica

2 F/year

U

Dominican Republic

260 F (1980)

D

French Guiana

112 F (1979)

D

Grenada

200 F (1982)

U

15,750 pounda (1980-82)

Guada loupe

+

D

Guatemala

+

U

Guyana

+

D

Haiti

+

D

250 pounds/year

Honduras

+

D

Jamaica

100 F (1982)

D

4,980 pounds/year

Mexico

502 F (1981)

D

Harvested

Nicaragua

+

D

104,434 pounds (1980), 100 turtles

(1983)

Panama

+

D

Puerto Rico

4 F (1982)

D

St. Lucia

+

D

5 turtles/year

Surinam

4,500 F (1982)

S

250,000 eggs/year

Turks/Calcoa

75 F (1982)

U

4,000 pounds/year

United States

182 F/year

I

Venezuela (Aves I.)

200 F (1982)

u

PACIFIC OCEAN AND ADJA

CENT SEAS

American Samoa

+

. 1

I

Australia

No. 7 /No. 8 Sandbanks

Several hundred F/year

S

Bushy I.

Several hundred F/year

s

Bell Cay

Several hundred F/year

s

Australia

Raine I.

80,000 F/year

s

Lacepede Is.

10,000 F/year

s

Torres Strait

+

s

10,000 turtles/year

Cook Is.

+

u

Esster I.

+

u

Fed. Ststes of Micronesia

+

D

Harvested

Fiji

+

D

French Polyneala

+

D

Hawaiian Islands

■

French Frigate Shoals

750 F/year

S

Indonesia (Western)

25,000 F/year

D

Increasing harvest of eggs end adults

Japan

+

U

83,600-398,200 pounds (1959-1970)

H

Line la.

+

U

Kermadec I.

+

U

Malaysia (East)

+

D

401,400 eggs harvested/year

Mexico

+

U

New Caledonia

+

S

New Hebrides

+

s

Harvested

New Zealand

+

u

Panama

+

D

Papua New Guinea

+

D

Increasing harvest

Phlllppeana

+

Intensive commercial harvest

Phoenix la.

up to 200 F/year

U

1 Republic of Palau

1

D

...,

10

Table 1. (continued)

Location

Population Information

Trend 2/

Exploitation

Republic of the Ha ra halls

Bikar Atoll

711 breeding F

U

Society Islands

♦

D

Barveatad

Solomon lalanda

10 - 100 F/year

Harvested

Thailand

1,000 P/year

U

Tuamotu Archipelago

+

D

Kgge harvaatad

United Statea

+

(1

Weatern Saaoa

120 P/yaar

D

Barveated

INDIAN OCEAN AND ADJACENT SEAS

Bangladesh

+

D

Brltlah Indian Ocean Ter.

+

U

Burma

+

U

Comorea

1,900 P/yaar

U

Barveatad

Egypt

Abu-Rhodea

80 P/yaar

D

India

+

U

Increasing harvest of agga

and adults

Iran

300 P/year

8

Kenya

200 P/year

D

Barveated

Madagascar

+

0

Barveated

Halayala (Meat)

+

D

Barveated

Maurltlua

-

D

295 or more turtlea/year

Hayotte

500 P/year

D

Mozambique

200 P/yaar

D

Oiaan

7,000 P/year

S

Peoplea Dent. Rep. Yemen

10,000 P/yeer

S

Commercial harvest

Rep. South Africa

-

S

Raunlon

Europe

1,500 - 18,000 P/year

S

Tromelln

200 to more than 4,000 P/yaar

S

Saudi Arabia

500 P/year

s

Seychelles

2,500 P/year

D

Intensive harvest

Somalia

Several thouaand P/year

D

Commercial harvest

Sri Lanka

+

D

Harvested

Tantanla

+

U

Tonga

+

D

Harvested

Yemen

200 P/year

s

+ turtlea neat, but no population Information la available

turtlea no longer meet, but found In adjacent vatera

D decreaalng

P neatlng females

I Increasing

S stable

U no Information

1/ Based on information from numerous literature aourcea - see text references

7/ Population trends aa Inferred from literature aourcaa

7/ Includes both graen and leatherback aea turtlea

7/ Latest date of Information If known

5/ Creen and loggerhead aea turtlea combined

11

Population estimates since the species was listed in
1978 are still unavailable although sea turtle experts
believe there is a generally steady decline in stocks. King
(1982) has documented the decline of the Cayman Islands green
sea turtle fishery. The turtle fishery in Florida, Bermuda,
and the Dry Tortugas was also rapidly depleted by over
exploitation. Brongersma (1982) reports depletion of green
turtle fisheries at Bahia dos Tigres and Glandiole in west
African waters. Similar accounts of population declines are
reported from the Mediterranean Sea, the Pacific Ocean and
adjacent seas, and the Indian Ocean and adjacent seas.

Listing Factors

1. The Present or Threatened Destruction, Modification or
Curtailment of its Habitat or Range

Green sea turtles are found in estuarine and offshore
coastal waters that provide breeding, nesting, feeding, and
developmental habitat. The natural habitats of the green sea
turtle are being encroached upon as a consequence of
increased human population growth along the coastal areas.
In many areas, green sea turtle habitat has been lost,
altered, or degraded by development, recreational activity,
dredge and fill for land development, sea bed mining,
construction and maintenance of navigation channels, and the
discharge or spills of pollutants ( Coston-Clements and Hoss,
1983).

These habitat losses are not limited to developed or
industrially based nations but also occur in lesser developed
nations and other political entities as they strive to keep
pace with the world economy, and, at the same time, deal with
expanding human populations. However, such diverse areas as
Hawaii (U.S.), American Samoa (U.S.), the Trust Territory of
the Pacific Islands, Indonesia and India demonstrate that
habitat degradation is not necessarily the result of economic
or political status.

Green sea turtles may be adversely affected by the
following activities (McFarlane, 1963; Coston-Clements and
Hoss, 1983):

1. Domestic development — including artificial lighting,
man-made barriers, rip-rap, jetties, beach cleaning
and traffic;

12

2. Industrial deve lopment--t hernial discharge,
agrobusiness, radioactive waste, insect control, and
trace metals;

3. Pollution—including spills of oil and hazardous
materia Is ;

4. Dredging and mining; and

5. Predators attracted to human refuse.

Other habitat alterations that affect green sea turtles
include the introduction of exotic vegetation by man on
nesting beaches and pollution of the turtles' oceanic
habitat. Exotic vegetation may inhibit nesting by forming
barriers and dense root mats (Hopkins and Richardson,
1982). The currents which accumulate sargassum weed, where
some green sea turtles may spend the early part of their
cycle (Pritchard, 1979), also accumulate pollutants such as
oil, styrofoam, and other plastic (Groombridge , 1982; Witham,
1978). Numerous young green sea turtles have been found dead
or moribund along Florida beaches with their jaws and throats
obstructed by tar (Groombridge, 1982).

While the loss of nesting habitat and its effects on
green sea turtles is unquant if ied, with diminishing nesting
and feeding habitat, the distribution of green sea turtles is
being reduced as well. Further, if separate breeding
aggregations do exist, as is now suspected in many instances,
then the loss of nesting habitats will lead to the eventual
extinction of certain stocks or races. Available information
also suggests that chemical pollution (e.g. oil) may be
adversely affecting green sea turtles and could pose a threat
to their survival (Groombridge, 1982).

2. Overu tilization for Commercial, Scientific or Educational
Purposes

The NMFS does not believe the use of this species for
scientific and educational purposes constitutes a cause for
declines in stocks. In the United States, this form of take
is regulated by a permit system designed to protect
endangered and threatened species. Much research on the
green sea turtle involves population surveys and ways to
increase its numbers. Therefore, research benefits rather
than harms these turtles.

13

The greatest cause for decline of this species is the
use of adults and eggs for food. In addition, small turtles
are stuffed for curios, the skin is used for leather, and the
shell is used for jewelry. Green sea turtles are prized for
their meat, calipee/calipash, fins, etc. Soup made from
various parts of this species is especially prized.

Declines in stocks due to commercial exploitation is
perhaps more evident for the green sea turtle than other sea
turtles (Table 1). Stocks were almost decimated by 1900.
King (1982) recounts the fate of several of the largest green
sea turtle rookeries. The Cayman Islands is believed to have
supported one of the largest known rookeries. Extensive
exploitation for food decimated the population by the late
1700s. The population was extinct by 1900, and the fishermen
moved to Nicaragua to harvest turtles. Nicaragua began
large-scale harvesting of green sea turtles in 1970,
processing an average of 10,000 turtles per year for shipment
primarily to the United States. This endangered the sea
turtle rookery nesting at Tortuguero, Costa Rica.

In Florida, similar depletion of stocks is evident. The
green sea turtle fisheries of the Indian and Halifax River
estuaries ceased in 1900 for lack of turtles, and the nesting
population of the Dry Tortugas was destroyed within 100 years
of the start of exploitation (King, 1982).

Hildebrand (1982) reports that a cannery for green sea
turtle soup began operation in Texas about 1849. By 1900,
turtle supplies were so low that the industry shut down. In
the past, at least 30,000 turtles (not all greens) were
caught in the Mediterranean off Israel with similar numbers
caught off Turkey (Sella, 1982). Green sea turtle rookeries
of Bermuda were decimated by 1620 (King, 1982). Similarly,
other declines in stocks are reported in the final
environmental impact statement prepared by NMFS and FWS for
listing the green sea turtle under the Endangered Species Act
of 1973.

Commercial exploitation of wild green sea turtles has
now been greatly curbed. However, Cayman Turtle Farms owned
by the Government of the Cayman Islands still exports green
sea turtle products, but not into or through the
United States. Also, Mexico and Ecuador may still be
exporting meat (Mack et_ a_l . , 1982). Green sea turtles are
still taken in Turkey and throughout the western Atlantic.
The remaining consumption of turtle meat is primarily local,
and, although its effects are unknown, continued use of

14

4

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J^SST*

'-■^

Green Sea Turtles.

Photos by Larry Ogren , Southeast Fisheries
Center, National Marine Fisheries Service.

15

depleted turtles can only further jeopardize this turtle's
survival prospects.

The consumption of eggs is probably local. The amount
of egg harvesting is not known except in Surinam where
250,000 eggs are harvested annually (Bacon _et_ _al_. , 1984).
However, in protein poor countries, and those without
protective laws for wildlife, the take of eggs is likely very
high which must impact the survival of green sea turtles.

3. Disease or Predation

Little is known about diseases and disease-induced
mortality of green turtles. Balazs (1980) has noted the
presence of apparently benign tumors ranging from small warts
to masses up to 25 cm. in diameter on 5 percent to 10 percent
of the green turtles observed while breeding at French
Frigate Shoals. Other organisms isolated from captive
turtles include the bacteria Salmonella weltevreden, and
Mycobacterium avium. The overall affect of disease on
natural populations of green sea turtles is not understood.

Adult green sea turtles are preyed on mostly by man.
Only sharks, whales, and large groupers would be able to take
adults and the larger subadults. The number of turtles lost
to natural predation and the effect of this take on the
population is unknown. However, predation on hatchlings and
eggs is usually very high. Hirth (1971) estimated that only
50 percent of the eggs hatch successfully, and only one to
three percent of the hatchlings reach sexual maturity. At
Tortuguero, Coasta Rica, Archie Carr once estimated that
survival from egg to sexually mature adult was probably 0.1
percent .

4. Inadequacy of Existing Regulatory Mechanisms

In the United States, green sea turtles probably are
adequately protected under the ESA. However, in other areas
of the world, laws and enforcement measures are not adequate
to protect this species and its products from international
trade and local consumption. The Convention on international
Trade in Endangered Species of Flora and Fauna (CITES) is not
universally accepted and some signataries continue to deal in
turtle products. Also, countries such as Japan, Germany, and
France have taken exceptions to the ban on trade in green sea

16

turtle products and still import meat, leather,
calipee/calipash, and shell.

Some of the major breeding colonies in and off the
Atlantic Ocean have been provided protection. However, the
population at Tortuguero, Costa Rica is stressed by harvest
in Nicaragua. Also, local consumption of adults and eggs is
believed to be very high (since much of their take is by
poaching, the extent cannot be quantified). Within the
Caribbean region, most existing laws afford only partial
protection (Bacon, 1981). Also, the region is so diverse and
large that the enforcement of existing laws is probably poor
to non-existant (see Carr et al . , 1982). Protection in the
Indo-Pacific region ranges from no protection at all for
adults or eggs to complete bans on harvesting for any
purpose. In many areas such as the Philippines and the
Seychelles, poaching for commercial uses as well as local
consumption occur despite laws and regulations prohibiting
such activities. In Australia, commercial harvest is for the
most part prohibited, but local take for subsistence purposes
is permitted and both activities are apparently controlled.

5. Other Natural or Manmade Factors Affecting its Continued
Existence

Severe weather conditions such as storms or heavy rains
may destroy eggs and hatchlings. Also, the natural erosion
of beaches as well as erosion during storms may impact
rookeries. For example, the nesting beach at Aves Island,
one of the larger green sea turtle rookeries in the Atlantic,
was almost entirely eroded in 1979 by Hurricane David.
However, the beach has been rebuilt and results of new
surveys of nesting on the island are being evaluated. Schulz
(1982) reported that Organabo Beach in French Guiana had also
eroded and virtually disappeared by 1979. Loss of foraging
habitat through natural causes such as siltation, sinking and
volcanic action can also adversely affect the distribution
and survival of specific populations of green turtles.
Volcanic action through lava flows forming new coastal lands
can also provide enhanced substrate for algae growths and
provide increased feeding areas.

Human Activities

The effect of human activities on turtle populations is
divided into two categories: the impact on nesting success

17

and the impact on oceanic survival (after Coston-Ciements and
Hossf 1983). Destruction or modification of nesting habitat
probably has the greatest impact on the ability of turtle
populations to maintain their numbers. Artificial
illumination from industrial or domestic development can
result in hatchling disorientation and a reduction in the
numbers of females coming ashore to nest. Offshore and
nearshore construction may also deter females from utilizing
preferred nesting beaches. Clearing of vegetation can reduce
shade and increase nest temperatures while also reducing the
structural rigidity of the nests by removing the root systems
of native plants. Construction of large buildings may
increase shade and lower nest temperatures. Since
temperature is an important factor in hatching success and
sex determination, even small changes may result in increased
mortality, imbalanced sex ratios and reduced hatching
success.

The impact of oil spills on nesting and hatching can be
considerable. Hatchlings entering the water during a
nearshore spill would suffer respiratory distress from the
volatile components of the oil and perhaps suffocation and
eye irritation from the heavier components. Nesting females,
if undeterred from coming ashore, could suffer similar
effects such as respiratory difficulty and eye irritation.
Oil spill clean up activities (vehicular traffic) can destroy
nests and prevent nesting by pregnant females.

Factors affecting oceanic habitat include pollutant
discharges, pesticide/herbicide spills and runoff, heavy
metal/radionuc lide discharges, PCB contamination, sewage and
domestic discharges, energy development, dredging/mining and
fishing activities. The discharges and spills of
hydrocarbons, heavy metals, biocides, and radionuclides
result primarily in the degradation of the physical health
and fitness of individual animals which can be manifested by
direct mortality, injury, body fouling, sensory disruption,
reduced reproductive success, and possible unknown
carcinogenic impacts. Secondary effects of these sources of
contamination range from destruction of foraging habitat to
disruption of breeding behavior. One possible positive
result of certain types of sewage discharge is the
enhancement of benthic algae utilized by green sea turtles
for food (Corps of Engineers, 1983).

Energy development impacts include entrapment in cooling
water intakes, dispersion or attraction to thermal effluent
plumes, and degradation of foraging and resting habitat by

18

effluent. A secondary impact of energy development is the
attraction of hatchlings to lighted offshore structures which
results in increased predation. The degradation of foraging
and resting habitat by mining and dredging can result from
disposal of spoil, alteration of bottom topography and direct
destruction.

Although fishing activities are not directly associated
with turtle harvesting, they can have significant adverse
effects through incidental entanglement and entrapment in
gear such as trawls, set nets, pound nets and gill nets (Tow
and Moll, 1982; deSilva, 1982; Hillestad et _al_. , 1982; and
Hopkins and Richardson, 1982). In the United States, an
estimated 432 green sea turtles per year are caught in shrimp
trawls with an estimated annual mortality of 97 (Bacon e_t
al. , 1984). Trawling activities also reportedly cause
significant mortalities off the Pacific coast of Panama, the
western Mediterranean (possibly 1,000 per year), Colombia,
Honduras, Australia, Ecuador, Peru, the Guianas, and Pacific
Central America (Groombridge , 1982). Turtles are also
incidentally taken in net fisheries (e.g. shark nets,
sturgeon nets, and pound nets), trap fisheries, and by hook
and line (Crouse, 1982). Hatchlings attracted to deck lights
may suffer significant mortality through enhanced
predation. Green turtles are also affected by fishing
methods using dynamite and chlorine bleach. Miscellaneous
impacts of fishing-related activities include ingesting and
entanglement in litter such as styrofoam, plastic, line, and
discarded netting.

Since few if any of these activities and their effects
have been quantified, an evaluation of their impacts, both
singular as well as cumulative, cannot be made at this time.

Conclusions

Overexploitation for its meat, calipee/calipash, skin,
eggs and other parts has led to the depletion of green sea
turtle stocks wherever they occur. Areas where populations
were decimated (e.g. Cayman Islands, Bermuda, and Dry
Tortugas) have still not recovered even though commercial
exploitation ceased before 1900. Reports by turtlers and sea
turtle experts throughout the world indicate most populations
are still reduced (e.g. King, 1982). The protected
population in Florida is showing some encouraging signs of
recovery, and the Surinam population as well as the nesting
colony at Tortuguero, Costa Rica may be secure.

19

In protein poor countries, the local consumption of
adult turtles and eggs continues to place great pressure on
this species. Also, because of the long time it takes for
sea turtles to reach sexual maturity, the relatively poor
survival rate of eggs and hatchlings, and the susceptibility
to predation and take due to its terrestrial nesting, the
species is still stressed and requires continued protection.

Therefore, NMFS believes that the best available
commercial and scientific data indicate that most of the
green sea turtle populations are depleted or endangered.
Information generated since the final environmental impact
statement submitted by NMFS and FWS in 1978 for listing and
protecting the green sea turtle is insufficient to warrant a
change in the status of the species. Accordingly, it is our
opinion that the green sea turtle should remain listed as
endangered in Florida and on the Pacific Coast of Mexico and
threatened in the rest of its range.

20

HAWKSBILL SEA TURTLE

( I r«tmoch«ly • Imbricate)

21

Hawksbill Sea Turtle
( Eretmochelys imbricata )

Biological Background

The hawksbill sea turtle is distributed throughout the
western hemisphere, where it also may be called the carey,
oxbull, tortue des bonnes ecilles, tortue imbriquee, karet,
and tartaruga de pente (Pritchard et at. , 1983). This sea
turtle can be recognized by four pairs of overlapping plates
on the shell except in very young and very old individuals;
two pairs of prefrontal scales (scales found between the
nasal opening and the eye socket) on the head; paddle-shaped
limbs with two claws, overlapping and serrate shell margins;
jaws that are modified and beak-like; and a rather long neck
compared to other sea turtles (Pritchard, 1979). The adult
shell is usually amber with streaks of red-brown,
black-brown, and/or yellow; the underside of the turtle is
whitish yellow and may have some black spots (Rebel, 1974).

Although the adult hawksbill is usually larger than
ridleys, it is smaller than other sea turtles. Shell length
(straight line) for nesting females examined from various
locations varied between 24.6 and 37.4 inches in the Atlantic
Ocean; between 23.6 inches and 36.5 inches in the Pacific
Ocean; and between 21 inches and 32.7 inches in the Indian
Ocean (Witzell, 1983). Weights for nesting hawksbills
examined from various locations varied between 60 and 190
pounds in the Atlantic Ocean; 80 and 170 pounds in the
Pacific Ocean; and 78 and 110 pounds in the Indian Ocean
(Witzell, 1983). Pritchard (1979) reports that the largest
record for hawksbills was a 37-inch long specimen, and the
heaviest weighed 280 pounds. There are no apparent external
morphological differences between subadult male and female
hawksbills. Adult males have tails that extend some distance
beyond the rear edge of the shell while the tails of females
are short, barely reaching beyond the rear edge of the shell

22

(Witzell, 1983). Also, the claws on males are longer and
heavier than on females and the underside is soft and
concave. The pigmentation of males may also be more intense
(Marquez, 1970; Witzell, 1983).

The longevity of hawksbills in the wild is unknown. A
specimen at least 16 years old was reported from the Berlin
Zoological Garden (Rebel, 1974) and Witzell (1983) cites an
alleged record of a 32-year old hawksbill. Carr et al.
(1966) believe that hawksbills mature sexually at about 78
pounds. However, in the wild, age to sexual maturity is not
known. Under favorable rearing conditions, Bustard (1979)
reported age to maturity at three to four years in
Australia. Witzell (1980) indicated that captive Samoan
hawksbills may reach maturity at about 3.5-4.5 years of
age. The age and size at maturity probably varies between
the sexes and individuals within breeding populations
(Witzell, 1983).

Hawksbills are ominvorous and eat plants and animals
such as algae, sea grasses, soft corals, crustaceans,
molluscs, sponges, jellyfish, and sea urchins (Carr and
Stancyk, 1975; Groombridge, 1982). The chief predators of
adults and juveniles include man, sharks, crocodiles, and
perhaps fish such as large groupers (Witzell, 1983).
Predators of eggs and hatchlings include man, feral hogs,
dogs, cats, insects, crabs, coatimundi, and lizards (Witzell,
1983). The loss of eggs and hatchlings to predation is very
high.

Hawksbills are a circumtropical species, preferring warm
shallow water areas that are usually less than 50 feet deep
(Carr and Stancyk, 1975; witzell, 1983). Coral reefs,
lagoons, shoals, and bays with good populations of plants and
animals are ideal habitats.

The non-nesting range of the hawksbill is extensive. In
the eastern and mid-Atlantic Ocean, hawksbills have been
reported from the European coast of the English Channel;
Mauritania, Senegal, Sierra Leone, Liberia, Ghana, Cameroon,
Gabon, South Africa, Morocco, Gambia, Togo, and Angola,
Africa; the islands of Madeira, Cape Verde, Ascension,
St. Helena, and Azores; and west of Cape St. Vincent, off
Portugal (Witzell, 1983). Hawksbills have been observed in
the Mediterranean Sea from France to its eastern coast.
(Witzell, 1983).

23

Distribution in the western Atlantic includes the area
from Cape Cod, Massachusetts to northern Brazil (Witzell,
1983). Hawksbills are rarely or occasionally encountered in
most of their distributional area in the western Atlantic
Ocean. However, Witzell (1983) indicates that hawksbills are
still common throughout the southern Gulf of Mexico, in the
Caribbean Sea, and the northern part of South America.

In the Pacific Ocean, hawksbills have been observed in
the Gulf of California as far as 29° north, throughout the
northwestern states of Mexico, and south along the Central
and South American coasts to Columbia and Ecuador (Witzell,
1983). Records are available from Revillagigedo Islands,
Galapagos Islands, Easter Island, the Hawaiian Archipelago in
the eastern Pacific and throughout the many island groups in
the Central and western Pacific (Witzell, 1983). There are
records of the hawksbill from the Sea of Japan, China,
Formosa, and from Indonesia to New Zealand in the western
Pacific (Witzell, 1983).

Hawksbills have been recorded also in the Indian Ocean
from Burma, Pakistan, the Persian Gulf, the Red Sea, South
Africa, and in many of the oceanic island groups (Witzell,
1983) .

Nesting sites are widely spread throughout the
hawksbill's range (Figure 2); they prefer to nest on small,
isolated beaches usually between the Tropics of Cancer and
Capricorn, except the Persian Gulf populations which nest
farther north (Witzell, 1983). Ideal nesting sites are on
clean beaches with more oceanic exposure and little
disturbance that would inhibit nesting. This species wanders
more in search of nesting sites and is more agile than other
sea turtles since it has the ability to climb over rocks,
vegetation, and other obstructions. It tends to nest among
the thick vegetation at the rear of the beach platform
(Mortimer, 1982).

Females typically nest in two or three year cycles (four
year returns are known), and deposit one to four clutches a
season at about 15 to 19 day intervals (Witzell, 1983).
Hawksbills are thought to be remarkably faithful to their
breeding beaches (Hughes, 1981). However, Carr and Stancyk
(1975) reported only a 4.6 percent return of 130 hawksbills
tagged at Tortuguero, Costa Rica. Clutch size usually varies
between 73 and 163 eggs which hatch in about 60 days (Hirth,
1980; Witzell, 1983). Most hatchlings emerge at night and
head directly to the sea where they are pelagic for some

24

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Hawksbill Sea Turtles.

Photos by Larry Ogren , Southeast Fisheries
Center, National Marine Fisheries Service.

26

time. Some hatchling hawksbills may drift in sargassum rafts
(Carr and Meylan, 1980a; Groombridge, 1982).

Population Size

Available population information is presented in
Table 2. This information is obtained from Groombridge
(1982), Bjorndal (1982), Hopkins and Richardson (1982), Carr
e_t _al_. (1982), Witzell (1983), and Bacon etal. (1984).

Female hawksbills generally nest alone and very quickly;
they are easily dissuaded from nesting by distributions on
the nesting beach. Moreover, diffuse and remote beaches are
preferred and nests are often hidden under vegetation.
Therefore, the hawksbill is a difficult turtle to census by
techniques such as aerial surveys. Because of the general
lack of intensive effort needed to survey hawksbill
populations, reliable estimates for population size are
generally not available. The number of reproduct ive ly active
females has been estimated for some populations, but Witzell
(1983) indicates that these estimates are apparently
unreliable or vary greatly from year to year.

The hawksbill is still widespread in tropical waters,
but nesting density is low in most of its range with moderate
nesting in only a few localities such as the Torres Straits
Islands; Jabal Aziz, Perim, and Seil Ada Kebir in the Red Sea
and Gulf of Aden; the Arnavon Islands; northern Australia;
Micronesia; the Maldives, Lavan, and Shetvar in the Persian
Gulf; Masirah Island, Oman; northern Madagascar; parts of the
Seychelles Republic; possibly at several sites in Indonesia;
Antigua; British and U.S. Virgin Islands; Grenada; Jamaica;
Mexico; and the Turks and Caicos (Groombridge, 1982; Bacon e_t
al. , 1984). However, it is generally accepted that most
nesting populations are declining due to habitat destruction
and over-exploitation (Witzell, 1983).

Listing Factors

1. The Present or Threatened Destruction, Modification or
Curtailment of its Habitat or Range

Destruction, modification, or curtailment of habitat or
range has not been quantified for the hawksbill. Therefore,
the effect of habitat loss or alteration on hawksbill
populations cannot be determined. Groombridge (1982)

27

Table 2. Population information, population trends and
exploitation of the hawksbill sea turtle
(Eretomochelys imbricata) 1/

ATLANTIC OCEAN AND ADJACENT SEAS

Location

Population Information

Trend 2/

Exploitation

Angullla

76 F (1982) 3/

D

Harvested

Antigua

-

D

108 lbs shell (1983)

Bahamas

+

D

13,866 lbs meat, 3,324 lbs shell (1980-82

Barbados

-

D

24 lbs shell (1982)

Belize

31 P (1982)

D

2,728 lbs shell (1982-83)

Bermuda

-

D

Harvested

British Virgin Islands

50 F (1981)

D

Harvested

Cayaen Islands

+

D

11,616 lbs shell (1981-82)

Colombia

+

D

Harvested

Costa Rica

+

D

699.6 lbs shell (1981-83)

Cuba

+

D

32,120 lbs shell (1981-83)

Dominica

3 P (1982)

D

306 lbs shell (1981-83)

Dominican Republic

420 F (1980)

D

3,249 lbs shell

French Guiana

+

D

Harvested

Grenada

500 F/year

D

33,000 lbs meat (1980-82)

Guadaloupe

+

U

Harvested

Guatemala

+

0

Harvested

Guyana

+

D

Harvested

Haiti

+

D

8,510 lbs shell (1981-83)

Honduras

+

D

6,607 lbs shell (1981-83)

Jamaica

300 F (1982)

U

6,266 lbs shell (1981-83)

Martinique

+

D

Harvested

Mexico

568 F (1981)

D

79 lbs shell (1983)

Nicaragua

25 F (1981)

D

19,714 lbs shell (1980-82)

Panama

+

D

20,115 lbs shell (1981-83)

Puerto Rico

22 F (1982)

D

Harvested

St. Lucia

11 F (1982)

D

1,978 lbs shell (1981-83)

St. Vincent

+

D

434 lbs shell (1981-83)

Surinam (Blglsantl)

29 F (1974)

D

Harvested

Trlnldad/Tobogo

+

D

724 lbs shell (1983)

Turks/Calcos

200 +/- 75 F (1982)

D

Harvested

United States

2 F/year

S

48 lbs shell (1983)

U.S. Virgin Islands

25 F (1982)

S

Venezuela

*

D

Harvested

PACIFIC OCEAN AN

D ADJACENT

SEAS

Australia (Torres Strait)

Several hundred/year

D

Harvested

China

+

D

Harvested

Colombia

+

D

Cook Island

•f

U

Costa Rica

+

D

Ecuador

+

D

Harvested

El Salvador

+

D

Harvested

French Polynesia

+

D

Harvested

Hawaii

+

D

Honduras

+

U

Harvested

Indonesia

+

D

35,000 hawksbllls/year

Japan

+

D

Harvested

Malaysia (East)

+

D

18,600 eggs harvested/year

Mexico

+

D

Harvested

Micronesia

+

D

Intensive harvest

New Caledonia

+

U

Nicaragua

+

U

Harvested

Panama

+

D

Harvested

Papua New Guinea

+

D

Intensive harvest

Philippines

+

D

5,000 hawksbllls/year

Solomon Islands

725 - 1,087 F/year

D

Intensive harvest

Thailand

4

D

Harvested

Western Samoa

+

D

Harvested

Tonga

+

'

Harvested

28

Table 2. (continued)

INDIAN OCEAN AND ADJACENT SEAS

Andaaan/Nlcobar Is.

♦

D

Sea turtles and their eggs harvested

Bum

+

V

Eggs harvested

Chagoa Archipelago

300 F/year

0

Coaores

50 F/year

D

Harvested

Ethiopia

♦

V

India

+

V

Harveeted

Iran (Gulf Islands)

400-600 F/year

V

Kenya

Leea than 50 F/year

V

Madagascar

■f

D

About 2,500 havkebll la/year

Maldives

+

D

Intensive harvest

Mozambique

Leea than 100 F/year

D

Oman (Omedu Beach)

50 - 80/year

D

Peoplea Dea. Rap. Yemen

Hundreds F/year

Qatar

+

D

Location

Population Information

Trend 2/

Exploitation

Reunion (Clorleuae)

50 F/year

D

Saudla Arabia

•f

D

Seychelles

More than 700 F/year

D

Intensive harvest

Sri Lanka

♦

D

Harvested

Sudan

350 or acre F/year

D

Tanzania

50 F/year

0

+ turtles neat, but no population Information la available

turtlea no longer neat

D decreaalng

F neatlng feaales

I Increasing

S stable

V unknown

1/ Baaed on Information froa numerous literature sources
T/ Population trenda aa Inferred froa literature sources
57 Lateat date of information If knovn

see text references

29

identified the loss of nesting beaches in Malaysia, Sri
Lanka, and the eastern Caribbean as a threat to this species.

The following summarizes habitat alterations that may
affect hawksbills (Coston-Clements and Hoss, 1983):

1. Pollution—includi ng spills and oil and hazardous
materials

2. Dredging and mining

3. Domestic development

4. Industrial development--thermal discharge,
agrobusiness, radioactive waste, insect control, and
trace metals

Female hawksbills are especially susceptible to
disturbance by light and moving shadows from people, animals,
trees, etc. during the early stages of nesting (Witzell,
1983). Disturbed turtles will rapidly return to sea without
finishing the nesting process (Carr ^t ^1_. , 1966). Witzell
(1983) reports that avoidance behavior is evident in areas
where the human population has moved near nesting sites and
built residences, resorts, military installations, airports,
and highways. Artificial lighting, physical barriers, and
vehicular traffic have been identified as development-related
activities that also affect hawksbills (Witham, 1982).

2. Overut i lization for Commercial, Recreational, Scientific
and Educational Purposes

The use of hawksbills for scientific and educational
purposes, while unquantif ied , is undoubtedly small and not a
contributing factor in the decline of hawksbill
populations. In the United States, the scientific take of
hawksbills is controlled by a permit program designed to
protect the species.

The main cause of depletion of hawksbill populations is
the exploitation of eggs, meat, shell, and whole young
animals (see Table 2). However, the greatest threat to
populations is the continuing demand for "tortoise shell",
i.e. the carapace, and plastral scutes of the animal
(Groombridge, 1982).

In many lesser-developed villages, hawksbill eggs are
eaten wherever and whenever found and are an important
protein source (Witzell, 1983). Surveys of important
hawksbill populations in Cays off the east coast of Nicaragua

30

in July 1971 showed that only 5 percent of the hawksbill eggs
laid were uncollected (Rainey and Pritchard, 1972). Also,
the meat generally is eaten wherever these turtles occur
although it is often reported to be dark and oily with a
strong flavor (Witzell, 1983). The hawksbill meat is
preferred over the meat from other sea turtles at Caymen
Brae, San Andres, and Old Providence Islands in the Caribbean
Sea and is eaten in other Caribbean areas, the Solomon
Islands, and New Guinea. Although, it is reportedly
poisonous in many areas of the world such as the Gulf of
Guinea, Australia, Sri Lanka, India, Mauritius, West Africa,
Seychelles, Senegal, Sudan, and Oman (Groombr idge , 1982;
Witzell, 1983). In a 1971 survey taken in Nicaragua, 50-60
percent of nesting females were killed (Rainey and Pritchard,
1972). Calipee is also prepared for consumption in many
parts of the world, and the oil and fat is often used for
cooking (Witzell, 1983). Other products from harvested
hawksbills include leather, oil, perfume, and cosmetics
(Witzell, 1983).

A major threat to the species is the collecting of
immature specimens that are stuffed and sold as curios to
tourists and the sale of polished whole shells. Main
producers of stuffed turtles and turtle shells for the
tourist trade are the Philippines, Indonesia, Thailand, the
Maldives, the Seychelles, Madagascar, Caribbean countries,
and Hawaii (Groombridge , 1982). Japan is a major consumer of
stuffed turtles, receiving virtually all of its supplies from
Singapore (Groombridge, 1982). The turtles traded at
Singapore come mainly from Indonesia (Sumatra) with some
obtained from Sulawesi, and a large number of very young
animals are reared in pens in Indonesia until they are large
enough for the curio trade (IUCN, 1982). Estimates for the
number of stuffed turtles produced annually in Singapore and
the Philippines range between 32,000 and 105,000. Stuffed
turtles are also common in the Caribbean region, but data on
the quantity is unavailable. It is illegal to bring curios
or other hawksbill products into the United States.

Another major threat to hawksbills is the use of the
scutes (tortoise shell) for medicinal and ceremonial
purposes, modern day articles, and especially for jewelry
(Witzell, 1983). The scutes removed from the shell are
reworked to produce hair pins, broaches, fans, belts,
miniature animals, inlayed furniture, eyeglass frames,
cuff-links, tie tacks, buttons, snuff boxes, jewelry boxes,
model pagodas, and model ships (Witzell, 1983).

31

Available catch statistics generally reflect only the
amount of shell produced, but cannot be used to determine the
number taken from the wild during the report period.
Although in some areas hawksbill shells may be stockpiled and
held to enter the market as higher prices encourage sales,
the trade in tortoise shell is probably greater now than ever
before. Indonesian exports increased from 22,000 pounds a
year between 1971 and 1977 to 483,087 pounds in 1978 (Mack et
al. , 1982). Exports from India, the Philippines, and
Thailand also increased as did exports from a number of Latin
American countries (King, 1982). Taiwan imported 6,600
pounds in 1974 to over 281,600 pounds in 1978. Since 1965,
Japan imported a minimum of 814,000 pounds of hawksbill shell
from Caribbean countries (Hopkins and Richardson, 1982).
Between 1981 and 1983, over 99,000 pounds of shell were
imported from various countries around the world (Table 2).

It is estimated that about 5,000 hawksbills are being
killed annually in the Philippines and 35,000 in Indonesia
( Groombr idge , 1982). Major exporters of shell are Indonesia,
Thailand, Philippines, India, and Fiji, while major importers
of shell are Japan, Taiwan, and Hong Kong (Groombr idge ,
1982). Japan and Taiwan import probably about 75 to 80
percent of the world's production of shell (King, 1982)
primarily in the use of jewelry and art objects that are a
part of their cultural tradition.

Because of the high prices the shell and items made from
the shells command, the continued exploitation of hawksbills
is virtually assured. A shell may be worth between $50 and
$59 a pound, and a large turtle may be worth $200 or more
(Carr and Meylan, 1980b). However, prices paid for preferred
shell in Japan have been as high as $102 per pound (Hopkins
and Richardson, 1982). Small items made from shell may cost
as little as a few dollars for hair clips and rings to as
high as $4,000 for eyeglass frames (Groombr idge , 1982).

3. Disease or Predation

Natural predation on hawksbills by carnivores is
probably very high although documented cases are scarce
(Witzell, 1983). Vaughn (1981), however, reported that 24
percent of nesting hawksbills in the Solomon Islands had
predator damage. Predation apparently is so common in some
places that Japanese longline fishermen cut open shark
stomachs to look for shell (Witzell, 1983). The effects of
predation on hawksbill populations are not known.

32

Published information on parasites and diseases of
hawksbills is incomplete (Witzell, 1983). However,
baranacles, several species of worms (usually trematodes),
amphipods, bacteria, a possible parasitic crab, hydroids,
bryozoans, and various algae have been found either in
hawksbills or on external surfaces (Witzell, 1983). The
effects of diseases and parasites on hawksbill populations
are not known.

4. Inadequacy of Existing Regulatory Mechanisms

The hawksbill receives adequate protection in the United
States because of the ESA; however, since the population is
not plentiful in this country, international protection is
vital to its survival. The hawksbill is listed on Appendix I
of CITES, but compliance is voluntary, and countries
subscribing to CITES may accept or not, at their discretion,
the bans imposed by this Convention. Unless widespread
acceptance of CITES (especially by Japan, Taiwan, and other
countries that import hawksbill products) is gained,
prospects for international protection of the species are not
good.

5. Other Natural or Manmade Factors Affecting its Continued
Existence

Natural forces that affect hawksbills, especially during
the nesting process, include storms, temperature, rain, and
wave surge (Witzell, 1983). These forces can prevent turtles
from nesting, destroy eggs and hatchlings, and reduce nesting
success. Hawksbills may also die of hypothermia when they
venture away from the tropics. However, the effects of
natural factors on the continued existence of the hawksbill
are unknown.

Hawksbills are incidentally taken in fishing operations
directed at other species. The effects of incidental take
are unknown, but may become important if population levels of
hawksbills decline further. They have been captured in pound
nets on the eastern United States coast; in fishing nets in
West Africa; in shark nets in southern Africa; in shrimp
trawls in Nicaragua, the United States, the Caribbean, and
other parts of the western Atlantic; and in fish gill nets in
India and Hawaii (Witzell, 1983). Divers fishing for
lobster, snapper, and grouper also spear hawksbills because
of the high price the shell brings (Groombr idge , 1982).

33

Also, hawksbills may become trapped in the ocean water
intakes of power plants and other industries.

Conclusion

Estimates of population sizes for hawksbills are
generally not available. The diffuse nesting habits and the
speed with which the female nests make this turtle difficult
to census. Also, since the hawksbill often nests under
vegetation, aerial surveys are generally not adequate, and
little information is available to adequately assess the
status of the species or to change its listing. King (1982),
Groombridge (1982), and Witzell (1983) report that the
decline of most nesting populations is generally accepted by
sea turtle researchers. The only known apparent stable
populations are in Yemen, northeastern Australia, the Red
Sea, and Oman (Witzell, 1983). The main factor leading to
depletion is over-exploitation which King (1982) indicates is
greater than ever before. The high price the shell commands
and the demand for hawksbill products will likely prevent
effective conservation of the species in the near future in
most of its range.

The NMFS believes that the best available commercial and
scientific data indicate that the hawksbill should remain
listed as an endangered species pursuant to Section 4 of the
Endangered Species Act. Considerably more information on
this species (e.g. population dynamics, life history, and
biology) is necessary before we can determine if any change
in the listing status of this species is warranted.

34

LOGGERHEAD SEA TURTLE

(Ccr«tt« ••r«tta)

35

Loggerhead Sea Turtle
(Caretta caretta)

Biological Background

In various parts of its range, the loggerhead sea turtle
also may be called lanternback, caguama, cabezona, logait,
onechte kaut, caguanne, and avo de tartaruga (Pritchard et
al. , 1983). It can be distinguished from other sea turtles
by five or more pairs of large boney plates along the margin
of the upper shell and two pairs of pre-frontal scales
(scales found between the nasal opening and eye sockets) on
the head; shell plates that do not overlap; paddle-shaped
limbs with two claws; a large, (up to 10 inches wide)
block-like head; and a shell which in adults is reddish brown
to brown on top and yellowish underneath and lacks pores
along the smaller plates along the margin where the upper and
lower shells meet (Pritchard, 1979).

The shell in full grown adults averages about 42 inches
long with a known maximum of 45 and 1/4 inches (Pritchard,
1979). Reports of turtles with larger shells are either
inaccurate or unsubstantiated (Pritchard, 1979). Adults
rarely weigh more than 350 pounds, but some very large
individuals weigh more than 500 pounds (Rebel, 1974).

There are no apparent external morphological differences
between the sexes of subadult turtles. Adult males have a
longer tail (extending well past the rear edge of the shell)
than adult females. The oldest loggerheads were recorded at
the Lisbon Aquarium where they died after 35 years in
captivity (Rebel, 1974). Longevity in the wild is not
known. Estimates of age to sexual maturity range between 4
and 30 years (Hopkins and Richardson, 1982; Groombridge,
1982). Loggerheads sexually mature at a weight of about 200
pounds and a shell length of about 31 inches (Pritchard,
1979) .

36

Loggerheads are mainly omnivorous feeding on shellfish,
crabs, hermit crabs, barnacles, oysters, conchs, sponges,
jellyfish, squid, sea urchins and sometimes fish, algae, and
seaweed (Carr, 1952; Brongersma, 1972; Rebel, 1974).
Predators of adults include man, killer whales, and sharks;
eggs are eaten by man, raccoons, dogs, rats, feral pigs,
foxes, crabs, etc; and hatchlings are eaten by gulls, crows,
raccoons, dogs, etc. (Hopkins and Richardson, 1982; Bacon e t
al. , 1984). Predation on eggs and hatchlings is very high
(Caldwell et _al_. , 1959).

Loggerheads can generally be found in warm waters on the
continental shelf and among islands where food is
available. They enter estuaries, coastal streams,
saltmarshes, and the mouths of large rivers (Carr, 1952).
This species is circumglobal , preferring temperate and
subtropical waters (McDiarmid, 1978). In the Atlantic Ocean,
it has been observed as far north as Murmansk, U.S.S.R., and
as far south as Rio de la Plata, Argentina, and is regularly
seen in the Gulf of Mexico and the Caribbean Sea (Brongersma,
1982; Carr et al. , 1982; Groombridge, 1982). Brongersma
(1982) cited records from the western coast of Europe,
Portugal, and the English Channel. Loggerheads also occur in
the Azores, the Madeira Archipelago, the Selvagens Islands,
the Canary Islands, in the Mediterranean Sea, and West
African waters. They have also been observed from the
Pacific coasts of Panama, Nicaragua, Chile, and possibly
Costa Rica, but not Peru (Pritchard, 1979; Brown and Brown,
1982; Sternberg, 1981). They occur along the Chinese coast,
Australia, and other areas in the western Pacific such as New
Guinea, New Caledonia and Noumea (Limpus, 1982; Sternberg,
1981). In the Indian Ocean, they occur off southern Africa
(Mozambique, Tongaland), Madagascar, Oman, Sri Lanka, Burma,
Pakistan, West Sumatra, Indonesia, and Thailand (Groombridge,
1982) .

The breeding range is "ant i tropical" (Pritchard, 1979)
with almost all nesting areas located north of the Tropic of
Cancer and south of the Tropic of Capricorn except for those
nesting in the western Caribbean (see Figure 3).

Loggerheads have been reported nesting from November to
January in Tongaland, South Africa; May to August in Florida
and South Carolina; and May to October at Masirah Island,
Oman (Ross and Barwani, 1982; Groombridge, 1982). Females
nest generally at night, depositing an average of 120 eggs
with a range of 72 to 130 on Masirah Island and 64 to 198 at

37

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38

Cape Romain, South Carolina (Caldwell et al. , 1959; Hirth,
1980).

Females typically nest four to five times per season,
but a maximum of seven nests has been recorded for a female
at Cumberland Island, Georgia (Groombridge , 1982). The
interval between nestings usually ranges from 14 and 17 days
(Pritchard, 1979). Most females nesting on a given beach are
never seen again (Hughes, 1982). The ones that do return to
nest have no universal remigration pattern; however, the most
commonly observed remigration interval is two to three years
(Hughes, 1982). At Tongaland, South Africa, females have
nested up to six seasons in a nine year period at the same
location (Groombridge, 1982).

The incubation period for the eggs is usually between 55
to 65.6 days with hatchlings typically emerging at night when
the temperature drops (Caldwell et al. , 1959; Pritchard,
1979). Hatchlings swim directly to sea where many may spend
the early part of their life associated with mats of
sargassum weed and other flotsam (Pritchard, 1979).

Population Size

Available population information is presented in Table
3. This information was obtained mainly from Bacon (1981),
Bjorndal (1982), Carr e_t _al_. (1982), Groombridge (1982),
Bacon e_t _al_. (1984), Murphy and Hopkins (1984), and other
sources cited in these publications. Population estimates
for loggerheads are difficult to obtain because so little is
known about their life history. Hatchlings and juveniles are
almost impossible to census in the water, the males never
leave the water, and it is difficult to tell males from
females in aerial surveys. Accordingly, most estimates are
based on the number of nesting females.

Listing Factors

1. Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range

In the United States, loggerheads are commonly found in
estuarine and offshore coastal waters which provide breeding,
nesting, feeding, and developmental habitat. The natural
habitats of the loggerhead are being encroached upon as a
consequence of increased human population growth along the

39

Table 3. Population information, population trends and
exploitation of the loggerhead sea turtle
(Caretta caretta)i/

ATLANTIC OCEAN AND ADJACENT SEAS

Locat Ion

Population Information

Trend 2/

Exploitation

Angola

Azores

Bahamas

Belize

Be rmuda

Brazil

Canary Islands

Cape Verde Islands

Caymen Islands

Colombia

Cuba

Cyprus

Dominican Republic

Greece

Grenada

Guatemala

Haiti

Honduras

Israel

Italy

Jamaica

Madel ra

Mexico

Netherlands Antilles

Nicaragua

Panama

Puerto Rico

Senegal

St. Lucia

St. Vincent

Turkey

Turks/Calcos

United States

+

+

+

+
40 F (1982)
Less than 2,000 F/year

+

+

+
400 F/year

+

+
60 F (1980) 3/
41.7 F/night (1981)
100 F (1982)

+

+

+

+

+

210 F (1982)

H

385 F (1981)

50 F (1982)
14,150 (1983)

Harvested

Harvested

9,620 pounds aeat (1980-82)

Harvested

Harvested

Harvested

Harvested
Harvested
Harvested

Harvested

9,900 pounds meat (1980-82)

Harvested

Heavy exploitation in past
2,000/year harvested in Sicily
Harvested
2,000/year (1979)
Heavy exploitation

Harvested

Harvested

Harvested

Harvested

Harvested

Harvested

Extensive harvest

Harvested

PACIFIC OCEAN AND ADJACENT SEAS

Aust ralia

Hon Repos

Capricorn /Bunker Is.

Wreck I.
China
Colombia
Indonesia
Japan
Mexico

New Caledonia
New Zealand
Panama

200 F/year (1967)
1,000 F/year (1972)
1,000 F/year (1981)

+
+
+
+
+
+
+
+

Harvested
Harvested
Harvested
Harvested
Harvested
Harvested
Harvested
Harvested

Harvested

INDIAN OCEAN AND ADJACENT SEAS

Burma

Madagascar
Malagasy Republic

Fort Dauphin
Mozambique (Paradls
Oman

South Africa
Sri Lanka

I.)

300 F/year

300 F (1974)
300 F (1974)
30,000 F/year
408 F (1978/79)

+

Eggs harvested
Harvested

Harvested
Harvested

Intense Harvest

+ turtles nest, but no population information is available

- turtles no longer nest

D decreasing

F nesting females

I Increasing

S stable

U unknown

1/ Based on information from numerous literature sources
see text references

2/ Population trends as Inferred from literature sources
3/ Latest date of Information if known

40

coastal areas. In many areas, loggerhead habitat has been
lost, altered, or degraded by development, recreational
activity, dredge and fill for land development, sea bed
mining, construction and maintenance of navigation channels,
and the discharge or spills of pollutants ( Coston-Clements
and Hoss, 1983). Little information is available on the
extent of this loss of habitat and how these activities
affect loggerhead populations. However, the available
information suggests that chemical pollution may be adversely
affecting loggerheads and could pose a threat to their
survival (Groombridge , 1982).

Loggerheads may be adversely affected by the following
activities (McFarlane, 1963; Coston-Clements and Hoss, 1983):

1. Domestic development—includi ng artificial lighting,
man-made barriers, rip-rap, jetties, beach cleaning and
traffic

2. Industrial development--thermal discharge,
agrobusiness, radioactive waste, insect control, and trace
metals

3. Pollution--including spills of oil and hazardous
materials

4. Dredging and mining and

5. Predators attracted to human refuse

Among the greatest threats to loggerheads are
development and increased use of nesting beaches by man
(Witham, 1982). Virtually the entire coastline of Florida,
where most loggerheads in the United States nest, is
developed, under development, or subject to development.
Also, only 33 miles of 88 miles of beach in Georgia are still
suitable for nesting (Lund, 1974).

Evidence that loggerheads do not prefer developed areas
is also suggested by movement of turtles from developed to
undeveloped beaches to nest. Increased nesting at Cape Sable
in the Everglades National Park may have resulted from
development of beaches outside the Park (Davis and Whiting,
1977). Declines in the successful nesting attempts by
loggerheads on Hutchinson Island have been attributed to
urban development (Williams-Walls et jal^. , 1983). In South
Carolina, increased nesting at Cape Romain National Wildlife
Refuge may be connected to increased development outside the

41

refuge, and, at Kiawah Island, nesting was observed to be
lowest in areas with beach homes and no restrictions on
lighting and traffic (Shabica, 1982). Areas in the
Mediterranean and Caribbean have been subjected to intense
development activities such as sand mining which have
adversely impacted nesting beaches (Sella, 1982; Groombridge,
1982). Also, concern has been raised about the rapid
development of a village near the largest loggerhead rookery
in the world at Masirah Island, Oman (Groombridge, 1982).

Other habitat alterations that affect loggerheads
include the introduction of exotic vegetation by man on
nesting beaches and pollution of the turtles' oceanic
habitat. Exotic vegetation may inhibit nesting by forming
barriers and dense root mats (Hopkins and Richardson,
1982). The currents which accumulate sargassum weed, where
some loggerheads may spend the early part of their life cycle
(Pritchard, 1979), also accumulate pollutants such as oil,
styrofoam, and other plastic (Groombridge, 1982). Numerous
loggerhead hatchlings have been found dead or moribund along
Florida beaches with their jaws and throats obstructed by tar
(Groombridge, 1982). Also, pieces of a plastic bottle were
found in a stranded loggerhead from Texas waters (Rabalais
and Rabalais, 1980) .

These activities remove available nesting habitat or
reduce the quality of available habitat which may reduce
nesting frequency or survivorship. Richardson and Richardson
(1982) predicted that in Georgia only 389 females from the
original cohort of 300,000 eggs will reach sexual maturity.
Accordingly, any permanent reduction in nesting or survival
would adversely impact the species.

2. Overut i lization for Commercial, Scientific, or
Educational Purposes

The NMFS does not believe the use of this species for
scientific and educational purposes is a cause for declines
in stocks. In the United States, this form of take is
regulated by a permit system designed to protect endangered
and threatened species. Much current research in the United
States and elsewhere mainly involves surveys of nesting
beaches and offshore areas for the presence of turtles and is
geared toward determining population size. Some research
also involves hatchery rearing of sea turtle eggs and
protection of the hatchlings from land-based predators.
Retween 1971 and 1982, at least 67,263 hatchlings were

42

released by such programs in North Carolina, South Carolina,
Georgia, and Florida (Bacon et al. , 1984).

The Endangered Species Act prohibits commercial
exploitation of the loggerhead in the United States.
However, exploitation occurs in many places around the World
(Table 3).

There is no reported commercial exploitation of eggs,
but local subsistence take and/or some poaching occurs
wherever the loggerhead nests (Hopkins and Richardson, 1982).

3. Disease or Predation

Little is known about the diseases of loggerhead in the
wild. However, Wolke (1981) discovered spirorchiasi s,
enteritis, anemia, spleenitis, hepatitis, gastritis,
nephritis, trematodiasis , myoceydilis, endocardiles ,
pneumonia, peritonitis, glomerulonephritis, nephrosis, and
nephrocalcinosis from postmortem examinations of 52
loggerheads from the U.S. Atlantic seaboard in March 1980.
Larval anisakid nematodes (Sulcascari s ) , tremadoes, and
cestodes were also reported from loggerheads (Sey, 1977;
Lichtenfels et al. , 1980).

e s t i ma t e

Predators of loggerheads have previously been
identified. Data is insufficient for a reasonable ^o^j.
of the extent of mortality due to disease and predation.
However, predation of eggs by raccoons is severe along the
southeast Atlantic seaboard of the U.S. (Pritchard, 1982b;
Groombridge, 1982).

4. Inadequacy of Existing Regulatory Mechanisms

In the United States, existing regulatory mechanisms are
believed to be adequate for the protection of loggerhead sea
turtles.

5. Other Natural or Manmade Factors Affecting Its Continued
Existence

On some beaches, natural processes may be a significant
source of mortality to loggerhead nests (Hopkins and
Richardson, 1982). Some nests are flooded by high tides if
placed too low on the beach. Also, severe storms, heavy

43

Ity *s^»

Loggerhead Sea Turtles

Photos by Larry Ogren, Southeast Fisheries
Center, National Marine Fisheries Service.

44

rains and high tides destroy nests. Beach erosion is another
source of egg mortality. Hypothermia or cold shock has been
identified as an additional source of natural mortality by
Wolke (1981). The effects of natural events on loggerhead
populations are unknown, but probably are not limiting for
this species.

Loggerheads are incidentally taken in industrial water
intakes (Witham, 1982) and in some dredging operations (e.g.
channel maintenance of the Port Canaveral ship channel in
Florida where 71 loggerheads were killed by dredging in
1980). However, the total level of this take is unknown.
Loggerheads are also incidentally taken in fishing operations
especially by bottom trawlers fishing for shrimp and demersal
fish (Rabalais and Rabalais, 1980; Shoop and Ruckdeschel,
1982). In the United States, an estimated 42,868 loggerheads
per year are caught in shrimp trawls with an estimated annual
mortality of 11,738 (Bacon et aj^. , 1984). Trawling
activities also reportedly cause significant mortalities off
the Pacific coast of Panama, the western Mediterranean
(possibly 1,000 per year), and Colombia (Groombr idge ,
1982). Trawling probably results in the incidental take of
loggerheads in Australia, Brazil, Guyana, Honduras, India,
Indonesia, Mexico, Sri Lanka, and Surinam. Turtles are
incidentally taken in net fisheries (e.g. shark nets,
sturgeon nets, and pound nets) trap fisheries, and by hook
and line (Crouse, 1982). The effect of incidental take on
the survival of the species is unknown.

Conclusions

Since the loggerhead sea turtle was listed in 1978,
adequate information has not been developed to assess whether
its status has changed. Loggerhead populations throughout
the world are still under severe pressure from local
exploitation. Also, some populations are known to have
declined. These include the populations in Honduras, Mexico,
Colombia, Israel, Turkey, Bahamas, Cuba, Greece, Japan, and
Panama (Ross, 19 82; Sella, 1982; Groombr idge, 1982).
Accordingly, NMFS believes that based on the best available
commercial and scientific information, the loggerhead sea
turtle should remain listed as threatened throughout its
range.

45

KEMP'S RIDLEY SEA TURTLE

(L«pldeeh«ly« k«mpl)

46

Kemp's Ridley Sea Turtle
( Lep idochelys kempi )

Biological Background

In various parts of its range, the Kemp's ridley sea
turtle also may be called the tortuga lora del Atlantico,
Atlantic ridley, Mexico ridley, grey loggerhead, tortuga boba
and bastard turtle (Pritchard et a.l. , 1983). Distinguishing
features are two pairs of prefrontal scales (scales found
between the nasal opening and the eye sockets) on the head;
five or more pairs of large boney plates along the margin of
the upper shell with the first pair touching the
f oreward-mos t plate in the middle of the upper shell; paddle
shaped limbs with one claw; and pores along the smaller
plates bordering the upper and lower shells (Pritchard and
Marquez, 1973). The shell is heart-shaped to round and may
be shades of gray brown, black, or olive. The underside is
white in hatchlings and yellowish in adults.

As adults, the ridleys are the smallest of all sea
turtles. They usually weigh between 86 and 109 pounds, and
their shells usually range between 20 and 28 inches long.
Although subadult males and females look alike externally,
the adult male's tail extends some distance beyond the rear
edge of the shell while the adult female's tail barely
extends beyond this edge (Pritchard and Marquez, 1973).

Although ridleys maya be long-lived in the wild,
longevity is not known. In captivity, a life span of over 20
years has been observed (Ernst and Barbour, 1972). At sexual
maturity, which likely takes six or more years, ridleys have
a carapace length of about 26 to 27 inches and weigh about 80
pounds (Pritchard and Marquez, 1973; Pritchard, 1979).

Kemp's ridleys eat crabs, fish, jellyfish, squid,
snails, clams, starfish and probably some marine vegetation

47

(Pritchard and Marquez, 1973; Hildebrand, 1982). Predators
of adult turtles include primarily man and sharks; predators
of eggs and hatchlings include man, coyotes, crabs, vultures,
jackfish, red drum, and sharks (Pritchard and Marquez,
1973). Hatchling ridleys (probably olive ridleys) have also
been found in the stomach of a leatherback turtle (Rebel,
1974). Survivorship of Kemp's ridleys from eggs to adults is
very low (Marquez, et al. , 1982).

This species prefers sheltered areas along coasts and
frequents larger estuaries, bays, and lagoons. Based on
favorable temperatures, prevailing currents, and abundant
food, the estuaries and offshore waters of Louisiana may be a
primary developmental area and feeding ground (Hildebrand,
1982). The Tabasco-Campeche area of the Gulf of Mexico is
also a major feeding ground (Carr et al . , 1982). The
Atlantic coast of the U.S. may also be a part of the
developmental and foraging range of the species.

Adult Kemp's ridleys have been recorded mainly from the
Gulf of Mexico from Florida to the Mexican border and around
the Bay of Campeche. Juveniles occur in the same general
area, but are also found along the Atlantic coast of the U.S.
from Florida to New England (Lazell, 1980). Juveniles are
also reported from European shores and the Mediterranean Sea
(Brongersma, 1982). Kemp's ridleys in the Atlantic Ocean and
Mediterranean sea may have been passively carried from the
Gulf of Mexico and northward in the Gulf stream (Groombr idge,
1982). The fate of ridleys carried away from the Gulf of
Mexico is unknown. They may migrate back to the Gulf of
Mexico to mature and breed or they may be unable to return to
the Gulf and are lost to the reproductive portion of the
population ( Hendrickson , 1980; Groombridge, 1982).

Before its depletion began in the 1940 's, Kemp's ridley
was an abundant species along the Atlantic seaboard of the
U.S. from Florida to Massachusetts. Also, it occurred
regularly in New England waters and is still reported to be
seasonally common in Massachusetts (Lazell, 1980).

Nesting is mainly restricted to a stretch of beach from
Baha Coma to Boca San Vincente near Rancho Nuevo, Tamaulipas,
Mexico (Pritchard and Marquez, 1973). Occasional nesting has
been reported at Padre Island, Texas, and scattered nesting
reported at southern Veracruz, Mexico (Carr et al . , 1982;
Hopkins and Richardson, 1982). Marquez et al . (1982)
reported that on May 20, 1979, 20-30 nesting females came
ashore at Lauro Villar near the border between Mexico and

48

Texas (about 140 miles north of Rancho Nuevo). See Figure 4
for locations.

Nesting occurs in aggregations called arribadas (meaning
arrival) between April and mid-August during optimal weather
conditions such as cloudy, relatively cool days with a strong
north wind (Pritchard, 1979). Most returning females nest on
a one or two year cycle laying one to three clutches per
season at intervals of 20-28 days (Hirth, 1980). However,
most females are observed nesting only one time (Hughes,
1982). For example, of 1,038 females tagged in Mexico, only
17 returns were observed (Hughes, 1982). Clutches average
110 eggs (Pritchard, 1979). Incubation takes between 50 and
70 days with most hatchlings emerging about dawn after 53-56
days (Pritchard, 1979). Hatchlings enter the sea and swim
actively ("swimming frenzy") for hours or days after which
they drift with the currents and perhaps at times become
associated with rafts of floating sargassum weed (Pritchard,
1979). It is not known how long it takes for these turtles
to begin active swimming and diving.

Population Size

In 1947, about 40,000 turtles nested in one arribada
(Pritchard and Marquez, 1973). The number of nesting females
declined to about 5,000 in the mid 1960's; the largest
arribadas in 1970 and 1971 consisted of 2,000 to 2,500
turtles; and in 1973, the largest arribada included about
1,000 turtles (Pritchard and Marquez, 1973; Groombridge,
1982). By 1975, only about 500 females nested (Carr et al. ,
1982). Carr (1977) estimated the number of mature ridleys at
162,400 in 1947, 10,150 in 1970, and 4,872 in 1974.
Estimates of nesting females since 1975 are 656 in 1978; 754
in 1979; 693 in 1980; 705 in 1981; and 621 in 1982 (Bacon et
al. , 1984). There are no reliable estimates of the number of
Kemp's ridleys of all developmental stages (i.e., the total
population) .

Listing Factors

1. The Present or Threatened Destruction, Modification or
Curtailment of its Habitat or Range

Since 1966, the Kemp's ridley nesting beach in Mexico
has been protected with armed patrols. Moreover, the beach
is remote and has not been developed yet. This area, Playa

49

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50

de Rancho Nuevo, is one of seven proposed nature preserves
along the Mexican coast (Marquez, 1972; Groombridge, 1982),
and, presumably, it will be protected from development.
Accordingly, the nesting habitat is not yet threatened by
destruction or modification.

In its oceanic environment, the Kemp's ridley may be
adversely affected by the following activities and substances
(Coston-Clements and Hoss, 1983):

A. Pollutants from industrial and residential
development. These include oil, pesticides, herbicides,
radionuclides, PCB's, heavy metals, and sewage. The effects
of pollutants are difficult to detect and evaluate, except
for oil and tar balls that are known to have killed ridleys
by fouling and/or ingestion. The other contaminants may
cause physiological problems that can reduce the reproductive
success of this species. Frazier (1980) questions whether
the decline of Kemp's ridley is related to pollution
discharges from the Mississippi River.

B. Exploratory oil and gas drilling. These activities
may affect ridleys by attracting them to lighted platforms
where they may be susceptible to increased predation; by
disrupting feeding habitat when disposing of drilling muds
and sediments; and by discharging oil which may contaminate
turtles and cause irritation or permanent damage to eyes,
affect respiration, and produce abnormal behavior, etc.

C. Disposal of garbage at sea. Plastic and other
foreign materials that are ingested by turtles may cause
death. Also, turtles may be fouled by plastic which could
adversely affect survival if the animals are unable to shed
the plastic. Additionally, turtles attracted to refuse may
be subjected to more predators such as sharks which may also
be attracted to the refuse.

D. Dredge and fill. These activities may affect
habitat that turtles use or the equipment (e.g. dredge cutter
head) may harm or kill turtles if encountered during the
dredging operation. Louisiana estuaries, which may be
important developmental habitat, are being lost at a rate of
39 square miles per year (Fruge, 1981). This is due mainly
to land subsidence (sinking), canal construction, wetland
reclamation, sediment starvation, and natural and man-induced
erosion primarily from oil and gas exploration. Other
estuaries, such as those on the Atlantic coast of the United
States, may also provide developmental habitat, but they are

51

also subject to dredging and filling. However, we do not
know the amount of habitat loss in these areas and its effect
on sea turtles.

E. Power boats. Power boats can injure or kill sea
turtles .

2. Overu til iza t ion for Commercial, Recreational, Scientific
and Educational Purposes

Several factors such as intensive predation on eggs by
local people and coyotes, fishing for juveniles and adults,
and killing nesting adults for meat and leather led to the
decline of Kemp's ridley (Pritchard, 1979; Groombridge,
1982). Exploitation for eggs and meat is now illegal and,
presumably, the directed take of this species has been
reduced .

Since the scientific research on endangered species is
controlled by a permit system based on provisions of the ESA,
taking of Kemp's ridleys for research is not considered to
adversely impact this species.

3. Disease or Predation

Diseases and parasites identified for ridleys include
barnacles, hepatitis, nematodiasis and nephrosis (Wolke,
1981). Predators of eggs, hatchlings, juveniles, and adults
have previously been identified. We do not know the level of
mortality from disease and predation, and, consequently, the
impact on the population.

4. Inadequacy of Existing Regulatory Mechanisms

In the United States, the Kemp's ridley is protected by
the Endangered Species Act of 1973 (35 FR 18310) and has been
protected in Mexico since 1966. The species is also listed
under Appendix I of CITES, and trade of all Kemp's ridley
products are banned. Existing regulatory mechanisms are
believed to be adequate for the protection of Kemp's
ridley. However, this species has been reduced to such low
numbers that it may not recover (Groombridge, 1982).

52

Kemp's Ridley Sea Turtles.

Photos by Larry Ogren , Southeast Fisheries
Center, National Marine Fisheries Service.

53

5. Other Natural or Manmade Factors Affecting its Continued
Existence

During nesting seasons, severe weather conditions such
as storms and heavy rains could damage the production of eggs
and hatchlings. Some turtles also die of hypothermia when
trapped in areas where water temperature drops too low
(Lazell, 1980). However, the effects of these natural forces
on the population are not known.

Subadults and adults are taken by hook-and-li ne
fishermen and are incidentally caught in shrimp trawls, shark
nets, pound nets, etc. (Chavez, 1969; Groombridge, 1982;
Bacon et al. , 1984). There are too few data to reliably
estimate the numbers caught or killed by hook and line, shark
nets, and pound nets. In U.S. waters, the incidental take of
Kemp's ridley sea turtles in shrimp trawls was estimated to
be 843, of which 27 5 died, each year from 1980 to 1982 (Bacon
JLlL iLL* ' 1^84). Kemp's ridleys are also susceptible to being
taken by industries such as power plants that have sea water
intakes. Power plants located from Florida to New Jersey
have reported the incidental catch of sea turtles by their
cooling systems ( Coston-Clements and Hoss, 1983).

Conclusion

A number of man-induced and natural factors have
drastically reduced the number of nesting females (estimated
at 42,000) in the 1940s. Estimates of nesting females were
only 680 in 1977, 656 in 1978, 754 in 1979, 693 in 1980, 705
in 1981, and 621 in 1982 (Bacon et al. , 1984). Despite the
conservation efforts that have been undertaken since 1966,
this species has been so drastically depleted that recovery
may not be possible (Groombridge, 1982).

In 1963, a private effort was begun to transplant ridley
eggs to Texas beaches to start a new nesting population
(Lund, 1974). This was superseded in 1978 by an interagency
effort between the U.S. Fish and Wildlife Service, NMFS,
National Park Service, Texas Parks and Wildlife Department,
Florida Audubon Society, and the Mexican Government (Hopkins
and Richardson, 1982). This interagency program called for
increased protection of the nesting beach, an attempt to
establish a breeding site at Padre Island, Texas, by
transplanting eggs, and head-starting ridleys by raising them
for about a year at the NMFS Galveston Laboratory before
their release. Between 1978 and 1982, 17,855 hatchlings were

54

headstarted in the U.S. and Mexico and released in the Gulf
of Mexico (Bacon et al. , 1984). The benefit of these
programs cannot yet be determined since these projects need
to run for a long time before their effect on the Kemp's
ridley population can be assessed (Pritchard, 1981).

If widely used, the Trawling Efficiency Device (TED)
developed by the National Marine Fisheries Service would
reduce the number of Kemp's ridleys incidentally taken in
shrimp trawls by more than 90 percent.

The best available commercial and scientific information
indicates that the Kemp's ridley sea turtle is severely
depleted and in danger of extinction. Therefore, this
species should continue to be listed as an endangered species
throughout its range.

55

OLIVE RIDLEY SEA TURTLE

<L«pl4oeh»ty» otfvac**)

56

Olive Ridley Sea Turtle
( Lep idochelys olivacea )

Biological Background

In various parts of its range, the olive ridley sea
turtle also may be called tortuga golfina, tortuga bestia,
manila, mani, batali, Pacific ridley, warana, tortue
olivatre, xibirro, carpintera, penyu lipas, penyu rantau, and
penyu abu abu (Pritchard and Trebbau, 1984; Pritchard et al . ,
1983; Tow and Moll, 1982; Suwelo et aj.. , 1982). Its
appearance is similar to the Kemp's ridley, but it has a
thinner, more narrow shell and a smaller, more lightly built
skull. The upper shell also is generally higher than Kemp's
ridley and has a greater variation in the number of plates
(five to nine pairs). Other characteristics are two pairs of
prefrontal scales (scales found between the nasal opening and
the eye sockets) ; a pore near the rear of the plates
bordering the upper and lower shells; and shell plates that
do not overlap (Pritchard e_t jal_. , 1983). The shell is
heart-shaped to round and may be gray brown, black, or
olive. The underside of adults is usually yellow but is
white in immature turtles and grey to black in hatchlings.

As adults, the olive ridleys are the smallest of the sea
turtles. They may weigh as much as 100 pounds with shells
generally between 24 and 30 inches long. Although subadult
males and females look alike externally, the adult male's
tail extends some distance beyond the rear edge of the shell
whereas the adult female's tail is much shorter (Pritchard et
al. , 1983). Males also have one of two claws on each
forelimb enlarged and strongly curved (Pritchard and Trebbau,
1984).

Olive ridleys may be long-lived in the wild, but exact
longevity is not known. At sexual maturity, which likely
takes at least seven to nine years in wild populations, the

57

shell usually is about 24 to 25 inches long (Cornelius and
Robinson, 1983), and the turtle weighs about 80 pounds
(Pritchard, 1979).

This turtle has been observed eating fish, crabs,
snails, oysters, jellyfish, sea urchins, fish eggs and
vegetation (Ernst and Barbour, 1972). Olive ridleys are
believed to be capable of feeding far offshore and forage at
great depths (Groombridge , 1982). Predators of adults are
primarily man, sharks, and large cats such as jaguars and
cougars on particular beaches. Hatchlings and/or eggs fall
prey to man, crabs, birds, fish and other mammals such as
coyotes, pigs, coatimundi, and feral dogs (Dodd, pers.
comm. ) . Survivorship from eggs to adults is probably very
low (Marquez et al. , 1982).

Preferred habitats are tropical bays and lagoons. In
the South Atlantic, primary foraging areas are located
between French Guiana and Venezuela and along the west
African coast between Congo and Mauritania. In the Indian
Ocean, foraging areas are found along Mozambique, east
Africa, Madagascar, Sri Lanka, and the east coast of India.
In the Pacific Ocean, the main foraging areas are between
Columbia and Mexico, along the northern coast of Australia,
Vietnam, Malaysia, and Indonesia, (Ernst and Barbour, 1972;
Rebel, 1974).

Nesting sites have been identified throughout tropical
areas around the world (Figure 5). Major nesting beaches are
located along the Pacific coast of Mexico and Costa Rica and
the east coast of Malaysia (Sternberg, 1981). In the
Atlantic Ocean, the main nesting beaches are in Surinam
(Bacon et al. , 1984). India, Pakistan, Mozambique and the
Andaman Islands have major nesting aggregations within the
Indian Ocean (Ross, 1982; Sternberg, 1981).

Nesting usually occurs in aggregations called arribadas
(meaning arrival) on mainland beaches during nights with
strong winds (Groombridge, 1982). Specific nesting times
vary with location. For example, nesting occurs year-round
in Costa Rica (Dodd, pers. comm.), between June and July in
Surinam, into August in Pacific Mexico, and from September to
November in other areas of the East Pacific (Pritchard, 1979;
Cliff ton et al. , 1982). Females usually nest in intervals
ranging from 14 to 48 days, depositing two to three (average
1.4 in Surinam) clutches of eggs (Groombridge, 1982). Mean
clutch size varies usually between 105 and 116 eggs which
hatch in 50 to 70 days (Groombridge, 1982). Most hatchlings

58

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59

emerge at night and little is known about the juvenile and
subadult phases of the life cycle since these stages have
been only rarely observed at sea. Most returning females
nest annually, but remigrations (return of females to nest in
succeeding years) have been observed in 2, 4, 5, and 6-year
intervals (Hughes, 1982).

Population Size

The population data presented in Table 4 are based on
information from sources in Sternberg (1981), Bjorndal
(1982), Groombridge (1982), Cornelius and Robinson (1983),
Bacon et al . (1984), Pritchard and Trebbau (1984), and
others. There is not enough systematic information to allow
separation of olive ridleys into taxonomic subunits.
However, geographically and genetically different populations
likely exist. Therefore, consideration of this species as
other than a single species is ill advised and for purposes
of this review, the species is considered a single population
in the Indo-Pacific region and eastern Atlantic, and a single
population in the western Atlantic.

The population levels of olive ridleys that existed
before commercial exploitation or the numbers that now exist
are not known. Insight can only be gained into the decline
of these turtles based on the number of nesting females (sex
ratios have not yet been determined so the number of males
cannot be determined). Also, no information is available on
the number of hatchlings, juveniles, and subadults in the
water. The decline in nesting females and the low frequency
of encounters with turtles in the wild provides inferential
evidence that populations are generally declining. For
example, of all known nesting locations, only in Australia (a
minor nesting location) is the population considered stable.

Where more complete information is available, especially
in the major nesting regions, alarming declines in the
remaining olive ridley populations are evident. Pacific
Mexico supported an estimated 10 million adults before 1950;
an estimated 1,185,000 adults (including 593,667 females)
prior to 1969; and 485,000 adults in 1976 (Cliff ton et al. ,
1982). In the early 1970s, between 179,000 and 400,000
nesting females arrived at various beaches in Mexico
(Groombridge, 1982). Only the Oaxaca beaches (La Escobilla)
still support large-scale nesting populations (Cliffton e t
al. , 1982). The breeding populations at other Mexican
beaches have reportedly all but disappeared (Cliffton et al . ,

60

Table 4. Population information, population trends and
exploitation of the olive ridley sea turtle
(Lepidochelys olivacea) 1/

ATLANTIC OCEAN AND ADJACENT SEAS

Location

Population Information

Trend 2/

Exploitation

Angola

♦

U

Mainly egga harvested

Brazil

+

U

French Guiana

♦

0

Guyana

+

D

Senegal

+

U

Surinam

550 F (1977) J/, *50 P (1978),

400 F (1979), 500 F (1980),
600 F (1981)1 400 F (1982)

D

Venezuela

+

D

PACIFIC OCEAN AND ADJACENT SEAS

Australia

+

S

Colombia

♦

U

Coaca Rica

S

Nanette

221,000 F/yaar (1982)

0

Ostional

260,000 - 435,000 F/year (1982)

D

Intensive egg harvest

Ecuador

-

D

290,000 - 320,000 adulta (1978-1981)

El Salvador

♦

0

Harvested

Guatemala

♦

D

Commercial egg harvest

Indonesia

♦

U

Harvested

Honduras

3,000 F/ye*r

D

Harvested

Malayaia (Eaat Coast)

♦

0

305,000 eggs/year harvested

Mexico

79,900 adulta (1983)

D

100,000 turtles/season

Nicaragua

12,475 F (1982)

D

100,000 eggs harvested (1983)

Panama

♦

D

Papua New Guinea

♦

D

Harvested

Peru

♦

0

Harvested

Philippine*

+

D

Harvested

Thailand

+

D

Harvested

61

Table 4. (continued)

INDIAN OC&AN AND ADJACENT SEAS

Burma

+

D

Harvaated

India (Orlaaa)

300,000 P/year

D

Intensive Harvest

Indonesia

+

D

Laccadivaa

+

U

Madagaacar

+

D

Harvested

Mozambique

500 - 1,000 neeta/year

D

Oman (Maalrah I.)

150 P/year

D

Harvaated

Paklatan

+

U

Reunion

♦

u

Sri Lanka

Savaral thouaand P/year

D

Harvaated

Tanzania

♦

U

+ turtlea neat, but no population information la available

turtle* no longer neat, but found In adjacent vatera

D decreaalng

P neatlng femalea

I lncreaalng

S atabla

U no Information

W Baaed on information from numeroua literature aourcea ~ aee text referencea
2/ Population tranda aa Inferred from literature aourcea
3/ Laceat date of Information If known

62

19 82). More recent population estimates for adult olive
ridleys from the Pacific coast of Mexico are 153,300 in 1981,
164,200 in 1982, and 79,900 in 1983 (Woody, pers. comm. ) .

The Surinam population of olive ridleys apparently has
undergone a startling decline in the number of nesting
females over the years (Bacon et al. , 1984; Pritchard and
Trebbau, 1984). The nesting population estimated at 2,100 to
3,000 females in 1967-68, dropped to an estimated 550-800
females in 1978 and 1979 (Schulz, 1982). Population
estimates are 550 nesting females in 1980, 600 in 1981, and
only 400 in 1982 ( Bacon et al_. , 1984). The survival
prospects for this population is poor possibly because of
killing of turtles in shrimp trawls (Schulz, 1982) and an
active market for skin in the leather trade (Hemley, 1984;
Roet, 1984). Even with protection, the olive ridley
population has dropped to low levels. Also, physical changes
in the nesting beaches may present a problem. Erosion and
deposition occur constantly. Presently, turtles must cross
extensive soft mud flats to reach the beach (Pritchard, pers.
comm.). These environmental changes may inhibit future
nesting by the olive ridley at Surinam.

Nesting populations at Nancite and Ostional, Costa Rica,
were considered fairly secure. However, the nesting
population at Ostional has dropped about 30 percent, probably
due to egg poaching. The nesting population at Nancite is
plagued by extremely low egg survival (Groombr idge , 1982).
Between 15 and 30 percent of eggs deposited during one
arribada may be destroyed by turtles nesting later
(Cornelius, 1982). Also, hatchling success may be lower than
one percent largely due to actions of ghost crabs, dipterans,
and infections by bacteria and fungi (Groombr idge , 1982;
Cornelius and Robinson, 1983).

Populations in India and Sri Lanka also may be
declining. Although sea turtles are protected there, the
poaching of eggs and adults is active, especially at Orissa
and West Bengal. Kar and Bhaskar (1982) believe that all the
sea turtle populations in India and Sri Lanka are declining
steadily. Even though sea turtles are protected, enforcement
of laws protecting these animals is poor.

63

Listing Factors

1. The Present or Threatened Destruction, Modification or
Curtailment of its Habitat or Range

Little information is available on effects of habitat
alterations on the olive ridley. Some recently cited adverse
impacts include development in the vicinity of Hawkes Bay and
Sandspit beaches in Pakistan for holiday accommodations that
is encroaching on the nesting area (Ross, 1982) and driftwood
washing up at Sarawak often blocks access to the nesting
beaches (Groombridge , 1982). Nevertheless, within its
distributional area, olive ridleys should be adversely
affected by habitat alterations to the same degree as other
sea turtles. The following list is provided as an example of
activities and substances that may adversely affect the olive
ridley sea turtle (Coston-Clements and Hoss, 1983).

A. Pollutants from industrial and residential
development. These include oil, pesticides, herbicides,
radionoclides, PCB's, heavy metals and sewage. The effects
of pollutants are difficult to detect and evaluate, except
for oil and tar balls that are known to have killed ridleys
by fouling and/or ingestion. The other contaminants may
cause physiological problems, such as reducing the
reproductive success of this species.

B. Exploratory oil and gas drilling. These activities
may affect ridleys by attracting them to lighted platforms
where they may be susceptible to increased predation; by
disrupting feeding habitat when disposing of drilling muds
and sediments; and by discharging oil which may contaminate
turtles and cause irritation or permanent damage to eyes,
affect respiration, and produce abnormal behavior.

C. Disposal of garbage at sea. Plastic and other
foreign materials that are ingested by turtles may cause
death. Also, turtles may be fouled by plastic which could
adversely affect survival if the animals are unable to shed
the plastic. Additionally, turtles attracted to refuse may
be subjected to more predators such as sharks which may also
be attracted to the refuse.

D. Dredge and fill. These activities may affect
habitat that turtles use, or the equipment (e.g. dredge
cutter head) may harm or kill turtles if encountered during
the dredging operation.

64

E. Power boats. Power boats can injure or kill sea
turtles.

2. Overut ilization for Commercial, Recreational, Scientific,
and Educational Purposes

The use of olive ridleys for scientific and educational
purposes, while unquant if ied, is small and not a contributing
factor in population declines. Research is geared toward
enhancing populations, and, therefore, benefits rather than
harms the species.

The local and commercial harvest (Table 4) of olive
ridley populations for meat, leather, and eggs ( Groombr idge,
1982) is the primary cause of depletion. For example, this
species is the most economcially important sea turtle in
Mexico where legal and illegal fisheries exist ( Groombr idge ,
1982). In the five years prior to 1969, Cliffton et al.
(1982) estimated that at least 2,000,000 olive ridleys were
landed by the legitimate commercial fishery. About 70,000
turtles were taken from La Escobilla in 1977, 58,000 in 1978,
and 24,500 in 1979 ( Groombr idge , 1982). The main turtle
processing plant in Mexico was nationalized in 1981.
Subsequently, the turtle quota set by the Mexican government
for the 1981/82 season was increased by 72 percent over the
previous season and allowed a take of 69,000 turtles (Mack,
1983). By December 1981, 56,000 turtles had been taken
(Hemley, 1984). The quota for the 1983/84 season was set at
50,000 turtles. Only 26,000 turtles were taken by December
1983, and an additional 2,000 were taken by the end of
January 1984 (Hemley, 1984) suggesting a substantial decline
in availability. The legal commercial harvest in Mexico is
overshadowed by poaching; Cliffton et ^]^. (1982) indicate
that millions of eggs and thousands of animals are taken
illegally each year— an estimated one million eggs were
poached at La Escobilla in 1969 alone.

From 1970 to 1977, between 132,000 and 147,000 adults
were harvested in Ecuador for the international skin trade
(Green and Ort iz-Crespo, 1982). From 1978 to 1981, the
harvest increased to between 290,000 and 320,000 adults as
estimated from the weight (approximately 1,273,000 pounds) of
skins that were exported (Hurtado, 1981). Although Ecuador
banned the export of turtle products in 1981, Japan imported
from Ecuador 18,623 pounds of skin in 1981, 74,272 pounds of
skin in 1982, and 6,600 pounds of skin thru October 1983.
While commercial exploitation has at least slowed in Ecuador,

65

^-- , „«— jfcg — - . .rwr ■'"...•.- -' *..".'

«|

Olive Ridley Sea Turtles:

Photos by Dr. Peter Pritchard,
Florida Audubon Society.

66

there are some indications that this activity has now shifted
to Colombia (Dodd, pers. comm. ) .

In India, _L. olivacea populations are being depleted
primarily by illegal harvest of eggs and turtles for food and
by human colonization of many nesting beaches (Kar and
Rhaskar, 1982). Apparently, thousands of turtles are taken
yearly off the coast of Orissa, one of the largest remaining
breeding colonies of L_. ol i vacea in the world (Kar and
Bhaskar, 1982). This take is reportedly increasing (Bobb,
1982). Also, more than 100,000 eggs were reportedly taken in
1982 at Gahirmatha alone and sold in Calcutta (Bobb, 1982).

In other areas where olive ridleys are found, such as
Pakistan and Sri Lanka, the take of turtles for human
consumption is very large (Kar and Bhaskar, 1982). Also,
hundreds of thousands of eggs are removed from Ostional
Beach, Costa Rica, each year (Cornelius, 1982). The removal
of virtually all of the olive ridley eggs at Eilanti,
Surinam, by the Carib Indians up until the late 1960s
(Pritchard and Trebbau, 1984) may have caused the drastic
decline there.

3 . Disease or Predation

Diseases and parasites of olive ridleys are not well
known. Predators of eggs, hatchlings, juveniles, and adults
have previously been identified. At Nancite, Costa Rica, an
extremely low percent hatch rate has been attributed to
bacterial and/or fungal contamination (Dodd, pers. comm.).
The level of mortality from disease and predation and the
effect on the species are unknown.

4 . Inadequacy of Existing Regulatory Mechanisms

In the United States, the olive ridley is protected by
the Endangered Species Act of 1973. It is listed as
threatened throughout the world, except the breeding colony
populations on the Pacific coast of Mexico which are
endangered. The species is also listed on Appendix I of
CITES which bans the trade of its products. Some large
importers, such as Japan, have taken reservations on this
species which means they still import products from olive
ridleys.

67

Nominal protection is afforded by legislation in much of

its range, but enforcement is often poor to non-existent.

Accordingly, the prospects for reducing the continued take of
this species is poor.

5 . Other Natural or Manmade Factors Affecting Its Continued
Exi stence

The effects of natural forces on the continued existence
of the olive ridley are not known. However, natural forces
that affect olive ridleys, especially during the nesting
process, include storms, temperature, rain, and wave surge.
These forces can create beach erosion or accretion, prevent
turtles from nesting, destroy eggs and hatchlings and reduce
nesting success. The build up of a huge mud flat in front of
the major olive ridley nesting beach in Surinam may pose a
threat to the population nesting there (Pritchard and
Trebbau, 1984).

An additional threat in parts of this turtle's range is
incidental catch by shrimp trawlers. This is considered to
be serious in the Pacific and in the Atlantic and is believed
to be a factor in the decline of the olive ridley in Surinam
(Schulz, 1982; Roet, 1984). Other fishing gears are also
believed to take olive ridleys (Pritchard, 1982).

Few, if any of the activities and their effects outlined
above have been quantified; thus an evaluation of their
impact, both singular as well as cumulative, cannot be made
at this time.

Conclusions

Overexploitat ion for its meat, skin, and eggs;
incidental take in various fisheries; and alteration of
nesting habitats has led to the depletion of the olive ridley
throughout much of its range. These factors continue to
deplete this sea turtle.

The NMFS believes the best available scientific and
commercial data indicate that most olive ridley populations
are experiencing declines. Information generated since the
species was listed is insufficient to warrant a change in the
listing status with the exception of the nesting populations
in the western Atlantic (i.e. Surinam and adjacent areas)
where the population has declined more than 80 percent since

68

1967. Accordingly, it is our opinion that the current
threatened and endangered status of the olive ridley should
remain unchanged except that the nesting population in the
western North Atlantic (Surinam and adjacent waters) should
be reclassified as endangered. This change in listing is
supported by numerous scientists and conservationists working
on sea turtle biology (e.g. Pritchard, pers. comm. ; Dodd,
pers. comm.; Ogren, pers. comm.; Carr, 1984; Meylan, 1984;
Bjorndal, 1984).

The NMFS in coordination with the Fish and Wildlife
Service should initiate appropriate action to propose the
above change in listing status.

69

LEATHERBACK SEA TURTLE

(Dirmoe

70

Leatherback Sea Turtle
( Dermochelys coriacea )

Biological Background

In various parts of its range, the leatherback is
commonly called the tinglada, leathery turtle, trunk turtle,
trunkback turtle, tortue luth, coffin back, siete filos,
chalupa, baula o laud, aitkanti, and tartaruga de couro
(Pritchard ^t_ al_. , 1983) and luth (Rebel, 1974). It is
distinctive from other sea turtles and belongs to the family
Dermochelyidae. Characteristic anatomical features include a
barrel-shaped body covered with leathery skin (rather than
hard plates) ; a shell with five to seven ridges or keels
running lengthwise; an underside usually with five
longitudinal ridges; and very large front flippers
(Pritchard, 1971). It is usually black or dark brown on top,
white underneath, and often has white spots on the dorsal
surface (Pritchard, 1979).

Leatherbacks are the largest sea turtles with adults
measuring between five and six feet long and weighing about
800 pounds (Pritchard, 1979); the maximum weight is about
1300 pounds (Pritchard, 1979). There is little external
morphological difference between sexes, but the adult males
have longer tails than females. Because tagging programs
have not been conducted long enough or with sufficient
intensity to obtain age and growth data in the wild
(Pritchard, 1971), little is known about the lifespan of the
leatherback.

This sea turtle eats primarily soft foods such as
jellyfish and tunicates. On one occasion, hatchling ridley's
were found in a leatherback stomach from Pacific Mexico
(Rebel, 1974).

71

Predators of adult leatherbacks include man, killer
whales, sharks, and large cats such as jaguars (Pritchard,
1971; Bacon e_t _al_. , 1984). Eggs and hatchlings are eaten by
man, pigs, mongooses, dogs, ants, lizards, birds, crabs and
fish (Pritchard, 1971; Hopkins and Richardson, 1982).

Leatherbacks have a circumglobal distribution and occur
in the Atlantic, the Indian, and the Pacific Oceans
(Groombr idge , 1982). The species nests primarily on beaches
between 30 degrees north and 20 degrees south (Figure 6), but
regularly moves into temperate seas to feed. Leatherbacks
commonly range farther north than other sea turtles probably
because of their ability to maintain warmer body temperatures
over longer time periods (Frair, e_t_ jal_. , 1972).

In the Atlantic, the leatherback regularly occurs off
New England (especially Massachusetts and the Gulf of Maine)
and in the Gulf of Mexico off the United States (Lazell,
1980; Leary, 19 57). Also, they have been reported from
Canada, the British Isles, Iceland, Europe, Spain (Pritchard,
1971; Brongersma, 1982), and Mar del Plata, Argentina to the
south (Carr, 1952). In the Pacific, the species has been
recorded along the coast of South America, (especially
between Peru and Ecuador) as far north as Alaska in the
United States, off Australia, south of New Zealand, as far
north as the South China Sea, and occasionally in the Yellow
Sea (Chu-Chien, 1982; Groombridge, 1982).

More preferred nesting beaches for leatherbacks are
located on mainland shores (Pritchard, 1971). Coarse sand
beaches free of large debris and rocks and adjacent to deep
water are apparently preferred nesting sites. Although most
females nest up to seven times per season, a few nest eight
or nine times. The interval between nestings during one
season is usually from seven to 13 days (Pritchard, 1971).
Clutch sizes are variable, but usually contain between 50 and
160 eggs that hatch in 60-70 days (Pritchard, 1979). There
is little information on the period between nesting seasons,
but some leatherbacks are reported to wait two to three years
before nesting again (Rebel, 1974). Most females tagged
while nesting for the first time are never seen again
(Hughes, 1982).

The nesting season varies according to location. For
example, nesting has been reported in Surinam and Guyana from
May to early June (Pritchard, 1969); in Costa Rica from April
to mid July (Carr and Ogren, 1959); in Trinidad from March to
August (Bacon, 1970); in the West Indies from March to May

72

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73

(Schmidt, 1916); and in Tongaland, Natal from November to
February (Hughes et al. , 1967).

Population Size

Carr et_ al_. (1982), Bjorndal (1982), Groombridge (1982),
Bacon e_t _al_. (1984), and the papers by Dr. P. C. H. Pritchard
provide information about nesting females in various areas
throughout the world. These are summarized in Table 5.
Population estimates for leatherbacks are generally available
only for nesting females. Nesting females, nests, and crawls
can be readily observed. Since males, juveniles, and
hatchlings stay at sea, they are rarely observed and thus are
difficult to count (Groombridge, 1982).

Fitter (1961) estimated that 1,000 pairs of leatherbacks
existed in the world. However, based on the discovery of
additional nesting beaches, Pritchard (1971) estimated that
about 4,000 leatherbacks nested at Trengganu, Malaysia;
15,000 in French Guiana; at least 1,000 at Matina Beach,
Costa Rica; 200-400 each in Trinidad, Surinam, Tongaland and
Ceylon (south India); and perhaps at least 8,000 on the
eastern Pacific shores from Jalisco, Mexico to northern
Peru. Pritchard's estimate for the total number of breeding
females ranged between 29,000 and 40,000. Additional major
nesting was observed along the Pacific coast of Mexico in
Michoacan, Guerrero, and Oaxaca. An estimated 500 turtles
nested per night on a 25-mile long beach at Tierra Colorado,
Mexico between October and January (Pritchard and Cliffton,
1981). Based on the discovery of this nesting area,
Pritchard (1982a) increased his estimate of the number of
nesting females to about 100,000. Based on reports of two
additional nesting localities at Playa Chiriqui and Playa
Chanquinola, Panama, by Carr et al. (1982), Pritchard (1983)
increased his estimate of the total population of nesting
females to 120,000.

An aerial survey of a 19-mile beach on the north coast
of the Kepala Burung (Vogelkop) region of Irian Jaya provided
evidence of around 3,500 sea turtle nests; many were thought
to be leatherbacks (Groombridge, 1982). Similarly, aerial
surveys of beaches in Costa Rica provided evidence of nesting
by at least 600 leatherbacks (Bacon e_t^ aj^. , 1984). Also,
aerial surveys of the coastal area between Cape Hatteras,
North Carolina to Nova Scotia, Canada out to the 2,000 meter
depth contour revealed a minimum of 967 leatherbacks
(University of Rhode Island, 1981).

74

Table 5. Population information, population trends and exploitation
of the leatherback sea turtle (Dermochelys coriacea) jv

ATLANTIC OCEAN AND ADJACENT SEAS

Location

Population Information

Trend 2/

Exploitation

Angola

30 F (Dec, 1971) 3/

U

Anguilla

3 F (1982)

U

Antigua

1 P (1982)

U

1/year

Bratil

♦

0

Brltlah Virgin Ialanda

2 F (1982)

0

2/year

Colombia

100 - 230 P/year

u

Harvested

Coaea Eica

Use than 4,000 P (1982)

u

Dominica

3 (1982)

0

Dominican Ilapubllc

380 P (1980)

0

Intensive egg harvest

French Guiana

3,197 P (1979)

D

Intensive egg harvest

Granada

23 P (1982)

D

6,600 pounds (1980-82)

Guatemala

♦

U

Guyana

♦

0

Bar-vested

Honduras

+

0

Mexico

73 P (1982)

U

Ear-vested

Nicaragua

■f

U

Panama

Less than 1,000 P/year

0

Puarto Rico

26 P (1981)

0

St. Kltts-Nevls

Less than 20 P/yaar

D

St. Lucia

22 P (1982)

0

St. Vincent

+

U

Surinam

3,900 P (1977); 1,300 P (1978);

2,700 P (1979); 1,000 P (1980);

I

1,300 P (1981); 2,500 P (1982)

Trinidad and Tobogo

Less than 230 P/year

u

Harvested, especially eggs

United Statea

38 P/year

I

D.S. Virgin Ialanda

26 P (1981); 19 P (1982)

0

Venezuela

+

u

PACIFIC OCEAN AND

ADJACENT

SEAS

Australia (Quesland)

2 F/year

D

Coeta Rica

+•

0

Intensive egg harvest

China

♦

U

Harvested

El Salvador

+

D

Intensive egg harvest

Pijl

♦

D

Harvested

Indonesia

May be as high aa 2,000 P/year

0

Harvested, especially eggs

Malaysia (Eaat)

1,000 - 2,000 P/year

D

294,300 eggs/year are harvested

Mexico

About 30,000 P/year

U

Several hundred P/yeer

Nev Guinea

+

D

Harvested

Nicaragua

+

D

25,000 eggs (1983)

Panama

+

0

Harvested

Papua Nev Guinea

♦

U

Harvested

Peru

+

u

Harvested

Philippines

+

0

Harvested

Solomon Ialanda

+

0

Thailand

■¥

D

Harvested

INDIAN OCEAN AND

ADJACENT

SEAS

Andaman/Nicober Is.

*

U

Eggs harvested

Arabia

+

0

Intensive harvest

Burma

+

U

Ceylon

100 P/year

D

Harvested

India

+

D

Intensive harvest

Malaysia (Vest)

+

D

Eggs harvested

Oman

+

0

Harvested

South Africa

70 F (1977-78)

I

Sri Lanka

+

U

Intensive egg harvest

+• turtles nest, but no population information la available

turtles no longer nest

D decreasing

F nesting females

I increasing

S stable

U unknown _

1/ Baaed on information from numerous literature sources
- see text references

2/ Population trends aa Inferred from literature sources
37 Lataat date of information if known

Listing Factors

1. The Present or Threatened Destruction, Modification or
Curtailment of its Habitat or Range

Although there is little information on the effects of
habitat loss on the leatherback sea turtle, there is concern
about the loss of habitat due to development. For example,
development is reported to be a threat to the leatherbacks
nesting at Sandy Point, U.S. Virgin Islands (Anonymous,
1981). In India, granite blocks used to control erosion may
be preventing leatherbacks from using beaches along most of
the Kerala coast ( Groombr idge , 1982). Development along
Florida beaches in the United States (e.g. construction of
buildings, seawalls, groins, and rip-rap erosion barriers and
renour ishment of eroded beaches) may adversely affect
leatherbacks by eliminating or reducing the quality of their
nesting beaches. Also, beach mining has been implicated as
causing leatherback mortality (Bacon et al. , 1984).

In some locations, exotic plants introduced by man may
interfere with nesting by blocking the path of leatherbacks
or inhibiting nesting because of dense root mats or excessive
shade (Hopkins and Richardson, 1982). In its oceanic
environment, the leatherback is also vulnerable to fouling
and ingestion of petroleum and plastic products. For
example, Mrosovsky (1981) reported that 50 percent of the
non-breeding leatherbacks he examined had plastic or
cellophane in their stomach. Plastic can block the
leatherback ' s intestines causing death. However, the
magnitude of the effects of habitat destruction and
modification, or curtailment of range, on the leatherback are
not known.

2. Overu tilization for Commercial, Recreational, Scientific
and Educational Purposes

Although there is little trade in leatherback products
(Pritchard and Cliffton, 1981), and their meat is reportedly
not as palatable as other turtles because their flesh is oily
and malodorous, they are heavily exploited in some areas for
their flesh and eggs. Groombridge (1982) reports that
subsistence take of leatherback meat and eggs is increasing
througout its range (see Table 5).

The harvest of leatherbacks has been reported from
Mexico, Peru, Trinidad, New Guinea, Indonesia, the Solomon

76

Islands, the Caribbean region, and Larak Island in the
Persian Gulf. Each year, hundreds of leatherbacks may be
slaughtered in Pacific Mexico and elsewhere (Mrosovsky, 1979;
Pritchard and Cliffton, 1981). In October 1978, 167
slaughtered leatherbacks were seen on beaches of Peru
(Pritchard and Cliffton, 1981), and a local industry in that
country reportedly captures nonbreeding leatherbacks for food
(Ross, 1982). Bacon (1970) estimated that between 20 and 30
percent of the annual breeding population in Matura Bay,
Trinidad was killed. In Papua, New Guinea, and Indonesia,
adults are usually killed for food. Inhabitants of a single
village in the Ka i Islands near Irian Jaya , Indonesia
reportedly kill 100 leatherbacks each year, and similar
levels of exploitation occur in other areas of this region
(Pritchard and Cliffton, 1981).

The slaughter of leatherbacks occurs in Guyana where
females are killed because they are believed to be useless
(Hopkins and Richardson, 1982). Other reported takes of
leatherbacks are one per year from Antigua, two per year from
the British Virgin Islands, and 2,200 pounds per year from
Grenada (Bacon et al . , 1984). Leatherbacks are rendered into
oil for caulking boats in India and on Larak Island in the
Persian Gulf and for oil lamps in Papua, New Guinea (Ross,
1982; Groombridge, 1982). They are used for ceremonial
purposes in the Solomon Islands (Groombridge, 1982);
medicinal purposes in India and parts of the Caribbean
(Anonymous, 1981; Ross, 1982); and bait in Mexico and
Indonesia (Groombridge, 1982).

The take of eggs, which is increasing, probably
constitutes the greatest threat to leatherback populations
(Ross, 1982; Groombridge, 1982). Almost all the eggs laid in
Mexico and at Trengganu, Malaysia are harvested (Groombridge,
1982). Egg harvest at Trengganu has declined about 66
percent since 1956 (Siow and Moll, 1982). Declines in
populations of leatherbacks in Sri Lanka, India, and Thailand
are also probably due to egg harvesting (Ross, 1982). The
harvesting and poaching of eggs is also believed to be a
serious problem in the Dominican Republic, Trinidad, Peru,
and French Guiana (Ross, 1982; Fretey and Lescure, 1976) and
probably occurs throughout the nesting range of this species
(Groombridge, 1982).

In areas where eggs are protected from harvesting (e.g.
Surinam, the United States and South Africa), populations
have increased in recent years (Ross, 1982).

77

Little information is available on the effect of
utilization of the leatherback for scientific purposes. Work
with leatherbacks deals mostly with population surveys,
hatching programs, and other activities that do not involve
the loss of these animals. In the United States, the take of
leatherbacks for scientific purposes is controlled by a
permit system designed to protect endangered and threatened
species .

3. Disease or Predation

The impact of predation on the species has not been
studied, but predation probably is not a significant factor
affecting the survival of the species.

Little is known about diseases of leatherbacks.
Pritchard (1971) reported parasites such as barnacles,
trematodes, nematodes, and amoebae, and Wolke (19 81) reported
a case of enteritis.

4. Inadequacy of Existing Regulatory Mechanisms

In the United States, the Endangered Species Act and
CITES provide adequate protection for the leatherback.
However, in other parts of the leatherback ' s range, there is
large-scale poaching of eggs on many nesting beaches. The
nests at Trengganu, Malaysia are subjected to intense egg
harvest (nearly 100 percent of the eggs are harvested).
Elsewhere (e.g. Peru, Asia, India, Ceylon, Dominican Republic
and Mexico), eggs and adults are taken in large numbers.
Additional protective mechanisms and stricter enforcement of
existing laws are needed to adequately protect the
leatherback (Carr et al. , 1982). For example, only 7 of 19
known leatherback nesting beaches listed by Ross (1981)
receive some degree of protection.

5. Other Natural or Manmade Factors Affecting its Continued
Existence

Severe weather events such as storms, heavy rains,
erosion, and cold destroy adults, juveniles, hatchlings, and
eggs (Bacon e_t al_. , 1984). For example, erosion and
subsequent loss of eggs is reported to be severe in the
Guianas (Mrosovsky, 1983). Adult females often die on the
beach because they become trapped by obstructions and debris

78

(Fretey and Lescure, 1976). Leatherbacks often nest in
places where their eggs are destroyed by high tides, thereby
posing problems in conservation. For example, poor nest site
selection ranges from less than 2.5 percent in Malaysia to
around 40 percent in the Guianas and as high as 50 percent in
Surinam (Mrosovsky, 1983). In Surinam; French Guiana;
Tongaland, South Africa; Mexico; and Malaysia, at least two
million eggs are lost each year (Mrosovsky, 1983) due to poor
nest selection.

Incidental take in fisheries also results in mortality
of leatherbacks. Large mesh gillnets, longlines, shark nets
and shrimp trawls kill leatherbacks (Bacon e t a 1 . , 1984);
Groombridge, 1982). In the United States, each year, an
estimated 1476 leatherbacks are caught in shrimp trawls with
subsequent mortality estimated at 505. During February,
March, and April, 1979, Japanese longliners caught an
estimated 96 turtles of which 16 percent were identified as
leatherbacks. The remaining 84 percent were not identified
(Roithmayer and Henwood, 1982).

Leatherbacks are also incidentally captured in water
intakes of industrial facilities such as power plants. For
example, three leatherbacks were trapped in the St. Lucie,
Florida Nuclear Power Plant in 1979 and two were trapped in
1981 (Roithmayer and Henwood, 1982).

Conclusion

Populations appear to have declined in Trengganu,
Malaysia; India; Sri Lanka; Thailand; Trinidad and Tobago;
and French Guiana. Only four nesting populations larger than
1,000 females are known (Silebache, French Guiana; Trengganu,
Malaysia; Chacahua, Mexico; and Tierra Colorado, Mexico).
Most known nesting females are concentrated in only a few
nesting populations, and these are not under the control of
the United States.

By far, the greatest threat to the survival of the
leatherback is the excessive harvest of eggs. In some areas
(e.g., Trengganu, Malaysia), nearly 100 percent of the eggs
are harvested, and existing laws that are supposed to
alleviate this problem often are not enforced (Carr et al . ,
1982). Also, the direct and incidental take of leatherbacks
still occurs (Bacon jst_ jj^. , 1984; Groombridge, 1982) in many
areas .

79

The NMFS believes that the best available commercial and
scientific data indicate that the leatherback sea turtle
should remain listed as an endangered species throughout its
range pursuant to Section 4 of the Endangered Species Act.
The species is still subjected to intense egg harvest and
directed and non-directed take of adults which result in
adverse effects to local populations. Considerably more
information (e.g., population dynamics, life history, and
biological status) is necessary before we can determine if
any change in the listing status of this species is
warranted .

80

Leatherback Sea Turtles.

Photos by Larry Ogren , Southeast Fisheries
Center, National Marine Fisheries Service.

81

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