(DRAFT) - Taxonomy
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
TAXONOMY
NAME - TURTLE, SEA, HAWKSBILL
OTHER COMMON NAMES - TURTLE, SEA, HAWKSBILL; TURTLE, SEA, HAWKSBILL; TURTLE, HAWKSBILL; HAWKSBILL, ATLANTIC;TURTLE, SEA, HAWKSBILL, PACIFIC;TURTLE, SHELL and TORTOISE;EA; E'A;CAREY; CAREY DE CONCHA;TORTUGA DE CAREY; TORTUE CARET
ELEMENT CODE -
CATEGORY - Reptiles
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - REPTILIA,
ORDER AND SUBORDER - TESTUDINES,
FAMILY AND SUBFAMILY - CHELONIIDAE,
GENUS AND SUBGENUS - ERETMOCHELYS,
SPECIES AND SSP - IMBRICATA,
SCIENTIFIC NAME - ERETMOCHELYS IMBRICATA
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Hawksbill Sea Turtle
Eretmochelys imbricata (Linnaeus, 1766)
KINGDOM: Animal GROUP: Reptile
PHYLUM: Chordata CLASS: Reptilia
ORDER: Testudines FAMILY: Cheloniidae
The hawksbill sea turtle, Eretmochelys imbricata, is a small to
medium-sized sea turtle. The maximum authenticated weight is 280 lbs
(127 kg) but a specimen over 100 lbs (45.4 kg) is a large one today
(01). The head is small with a narrow sharp beak. There are two
pairs of prefrontal scales on the head. The carapace is lance-shaped
to shield-shaped. There are four pairs of costal scutes and the
first one does not touch the nuchal. Except in the very young and
very old the scutes are imbricated. This species is often called the
most beautiful sea turtle because of the "tortoise shell" color of
the scutes on the carapace. The plastron is yellow with a few dark
blotches.
The taxonomic history of this species has been fairly straight
foward. It was described in 1766 by Linnaeus under the name of
Testudo imbricata. One disagreement about the interrelationships of
the four genera in the family Cheloniidae has, with the passing of
Taxonomy - 1 (DRAFT) - Taxonomy
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
time and the accumulation of new evidence, been resolved. The
hawksbill, Eretmochelys, is more closely related to Lepidochelys and
Caretta than it is to Chelonia (02,03).
It is a common practice to recognize the Pacific and Atlantic
populations at the species or subspecies level. The Linnean name of
imbricata with a restricted type locality of the Bermuda Island is
used for the Atlantic form and Agassiz' specific name, squamata, with
a restricted type locality of Singapore is used for the Indopacific
form. In commenting on this arrangement, Smith and Taylor (04) cite
their failure to find characters for such a separation.
An abbreviated synonomy which covers American waters is as
follows:
Testudo imbricata Linnaeus, Syst. Naturae, 12th ed., 1766 p. 350.
Eretmochelys imbricata Fitzinger, Systema reptilium, fasc. 1,
1843, p. 30.
Eretmochelys imbricata imbricata.
Eretmochelys squamata Agassiz, Contribution to the Natural
History of the United States, Vol. 1, 1857, p. 382.
Eretmochelys imbricata squamata.
Eretmochelys imbricata bissa.
Common names used for this species include hawksbill sea turtle,
hawksbill turtle, Atlantic hawksbill, Pacific hawksbill sea turtle,
carey, tortue caret (France), carey de concha (Puerto Rico), tortuga
de carey (Mexico), and ea or e'a (Hawaii).
Taxonomy - 2 (DRAFT) - Status
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
STATUS
Coded Status
Florida; Federal Endangered
Florida; Officially Listed
North Carolina; Federal Endangered
North Carolina; State Listed
Puerto Rico; Federal Endangered
Puerto Rico; State Listed
Virgin Islands; Federal Endangered
Virgin Islands; State Recognized
E: Federal Endangered
Commercial
Commercial/consumption
Non-consumptive recreational
Aphrodisiac
Ornamental
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The hawksbill sea turtle (Eretmochelys imbricata) has been
designated an Endangered species in tropical seas throughout its
entire range pursuant to the Endangered Species Act of 1973 (50 CFR
17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C. 1531-1540), as amended.
Critical Habitat has been designated in Puerto Rico as follows
(50 CFR 17.95(c)):
(1) Isla Mona. All areas of beachfront on the west, south, and east
sides of the island from mean high tide inland to a point 150 m
from shore. This includes all 7.2 km of beaches on Isla Mona.
(2) Culebra Island. The following areas of beachfront on the north
shore of the island from mean high tide inland to a point 150 m
from shore: Playa Resaca, Playa Brava, and Playa Larga.
(3) Cayo Norte. South beach, from mean high tide inland to a point
150 m from shore.
(4) Isla Culebrita. All beachfront areas on the southwest facing
Status - 1 (DRAFT) - Status
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
shore, east facing shore, and northwest facing shore of the island
from mean high tide inland to a point 150 m from shore.
The Fishery Conservation and Management Act of 1976 asserts
exclusive management authority in an exclusive fishery conservation
zone 200 miles (322 km) wide over fish and "all other forms of marine
life".
The Marine Protection Research and Sanctuaries Act (MPRSA) of
1972 creates marine sanctuaries out of water areas above the
continental shelf. Three sanctuaries have been designated that
potentially protect sea turtle habitat.
The Coastal Zone Management Act of 1972 is designed to "preserve,
protect, develop, and where possible, to restore and enhance the
resources of the Nation's coastal zone for this and succeeding
generations."
The Pelly Amendment to the Fisherman's Protective Act provides
economic sanctions that can be used to influence foreign nations to
fish in a manner which will not decrease the living resources of the
sea.
The Land and Water Conservation Fund Act of 1965, The National
Wildlife Refuge System Adminsitration Act of 1966, and The Refuge
Recreation Act of 1972 all provide funds and administrative provisions
that can be used to acquire and protect sea turtle nesting habitat.
This species is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild animal
(alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation, or foreign law; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species while on
land (50 CFR 222.23 (a)).
NMFS -Responsible for management/recovery and law
enforcement/protection while this species is in water.
DOD -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public land under their control. Also responsible for
management/recovery on Department of Defense lands
(Sikes Act).
NPS -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
Status - 2 (DRAFT) - Status
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
public lands under their control. Also responsible
for conservation (Nat. Park System Organic Act - 16
U.S.C. 1, 2-3)/management/recovery on National Park
Service lands. Taking, possessing, or disturbing of
federally listed species is prohibited on NPS lands
(36 CFR 2.1, 2.2, and 2.3).
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: American Samoa
DESIGNATED STATUS: None.
STATE: Delaware and Virgin Islands
DESIGNATED STATUS: Recognized Endangered
ADMINISTRATIVE AGENCY: DE Dept. Nat. Resour. & Environ. Contam.
VI Dept. Conservation & Cultural Affairs.
STATE STATUTE: DE Code Annot., Title 7, Ch. 6, Sec. 601-604.
VI Title 3, Ch. 22, VI Code of Laws, Subsec.
406A; also Title 12, Ch. 9, Subsec. 318.
STATE: Florida, Guam, Hawaii, North Carolina, Puerto Rico,
Texas and the Virgin Islands
DESIGNATED STATUS: Endangered; PR designated Crit. Hab.
ADMINISTRATIVE AGENCY: FL Game & Fresh Water Fish Commission.
GU Dept. of Agriculture, Aquatic &
Wildlife Resources Division.
HI Dept. of Land & Natural Resources.
NC Wildlife Resources Commission.
PR Dept. of Natural Resources.
TX Parks and Wildlife Department.
STATE STATUTE: FL End. & Thr. Sp. Act of 1977, FL Stat.,
Sec. 372.072; and Admin. Code, Sec. 39-27.03.
GU Govt. Code of, Sec. 12325.4(e), (P.L. 15-36).
HI Revised Statutes, Subsec. 195D-4, 195D-5;
Administrative Rules of HI, Sec 13-124-3.
NC General Statute 113-134, 113-132, 143-239;
15 NC Admin. Code, Wildl. Resour. & Water
Safety, Subch. 10I, Endang. & Thr. Species.
PR Reg. to Govern the Mgmt. of Thr. & End. Sp. in
the Commonw. of PR, 1985; Law No. 83, "Fishing
Law".
TX 31 TX Administrative Code, Sec. 57.133
(127.30.09.003).
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The hawksbill sea turtle is listed in Appendix I of the
Status - 3 (DRAFT) - Status
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
Convention on International Trade in Endangered Species of Wild Fauna
and Flora (CITES). Japan and France have entered reservations to the
CITES listing. The hawksbill is also listed as endangered in the IUCN
Red Data Book, 1982, as well as the 1986 IUCN Red List of Threatened
Animals.
The hawksbill sea turtle is listed by Mexico in "Listas de
especies marinas en peligro extincion en Mexico," Instituto Nacional
de Pesca, Division de Biologia Pesquera, de la Secretaria de Industria
y Commercio (1973) in conjunction with Article X of the Western
Hemisphere Convention.
Legal protection to varying degrees exist in Costa Rica, Surinam,
French Guiana, Ascention Island, Tahiti, Fiji Islands, Kingdom of
Tonga, Australia, British Indian Ocean, Seychelles Islands, Mexico,
and South Africa, and some of the present and former Pacific Trust
Territories.
ECONOMIC STATUSES:
The hawksbill sea turtle has had commercial and subsistence value
for its shell, skin, meat and eggs. The very attractive shell is
still highly valued and taken commercially, especially in Japan.
Subsistence hunting continues as well. There is a growing curio trade
in stuffed juvenile hawksbills. The eggs are also believed by some to
be an aphrodisiac. In 1982 the hawksbill was featured on a stamp of
the Solomon Islands. Although not directly sought, hawksbills (and
sea turtles in general) attract great interest from tourists and SCUBA
divers who encounter them.
70/06/02:35 FR 08495/ - Listed as Endangered
78/05/24:43 FR 22224/22225 - Proposed Critical Habitat
79/03/06:44 FR 12382/12384 - Withdrawal of proposal for CH
79/05/21:44 FR 29566/29577 - Five year review
80/10/22:45 FR 70198/70200 - Proposed Critical Habitat
82/06/24:47 FR 27295/27298 - Designation of CH in Puerto Rico
84/11/09:49 FR 44774/44775 - Five year review completion & availabil.
85/01/03:50 FR 00278/00279 - Review regs. on take for subsistence
85/07/22:50 FR 29901/29909 - Five year review
87/03/02:52 FR 06179/06199 - Proposed rule; NMFS; TEDs
87/05/11:52 FR 17615/ - Reopen comment period on TEDs
87/06/29:52 FR 24244/24262 - Final rule - TEDs
87/07/07:52 FR 25522/ - Notice of 5-year review completion
Status - 4 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
COASTAL
OCEANIC
LAND USE -
Residential
Commercial and Services
Bays and Estuaries
Beaches
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Estuarine, intertidal BB2
Marine, intertidal BB2
Marine, subtidal UB
Marine, subtidal RF1
Marine, subtidal OW0
COMMENTS ON HABITAT ASSOCIATIONS -
The habitat requirements of the hawksbill sea turtle,
Eretmochelys imbricata, can be inferred from its distribution. It is
primarily an inhabitant of coralline reefs (08) but it is probable
that any hard substrate that will support the encrusting organisms on
which it feeds and provide "rock shelters" for resting will substitute
for coral. The reef should be shallow; no maximum depth is found in
the literature but Carr reported it on reefs at depths of 98.5 ft
(30 m) off Costa Rica. According to Causey (11) it is most abundant
on the Atlantic side of the Florida Keys in water of less than 16.5 ft
(5 m). Depth may change with size, but this is not discussed in the
literature on the species.
The species is a solitary nester or it may nest in groups. In
Florida, it is estimated that 2 females nest per year (08), and it is
known to nest on tiny islets (Soldier's Key, FL) or high energy
barrier island beaches at Jupiter Island, FL (12). It is a common
statement that the species prefers to nest high on the beach under
vegetation, and nesting is stimulated by rain (13,14). On Mona
Island, PR, nesting occured beneath overhanging brush, mainly guitaran
(Suriana maritima) or seagrape (Coccoloba uvifera) at the upper edges
of sand beach along the shore (31). Nesting sites may occur on or
adjacent to residential or commercial developments, and, therefore,
may be subject to adverse impacts from management or further
development of these lands.
The hatchlings are pelagic and it is postulated that in the
western Gulf of Mexico they passively float with blooms of the
bluegreen algae, Trichodesmium (15). In Florida one young hawksbill
washed ashore in the sargassum and had eaten sargassum (15).
The role of the hawksbill in the ecology of coral reefs needs
further investigation. Undoubtedly, there are associations with
preferred food organisms. In the Caribbean Sea this appears to be
encrusting organisms, particularly sponges (15).
Habitat Associations - 1 (DRAFT) - Food Habits
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
OMNIVORE
LIFESTAGE FOOD FOOD PART
General Detritus
General Coniferae
General Evergreen Trees-Flowers/Fruit/Seed
General Sponges
General Coelenterata
Food Habits - 1 (DRAFT) - Environment Associations
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Coastal Wetlands: Mangrove swamps
G Coastal Features: Reefs
G Coastal Features: Sandy offshore islands
Environment Associations - 1 (DRAFT) - Life History
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
The hawksbill sea turtle, Eretmochelys imbricata, is generally
classified as an omnivore (16,17) or as an omnivore scavenger (08).
There is little information on the food of the hawksbill in Floridian
waters, consequently the following description of the diet is from
other areas. On the basis of an extensive study in Costa Rica (18)
and a review of articles (08,15,17), the species is primarily a grazer
of attached invertebrates. The most important item in the diet is
sponge. Several species of demosponges are most commonly consumed.
In addition, hydroids, bryozoans, soft corals, sea anemones, ascidians
and plant material which includes algae, seagrasses, marine
angiosperms (probably the leaves of Thalassia sp. and Halodula sp.)
and terrestrial plant debris (mangrove fruits, leaves, bark, and wood)
are consumed. Little is known about the food of the pelagic
juveniles; gut content of a stranded juvenile in Florida was sargassum
(19).
HOME RANGE/TERRITORY:
Territoriality has not been documented in the hawksbill by tag
returns. Tagging both on the nesting beach and foraging grounds has
been limited, and there are no reported recoveries of Florida tagged
hawksbills. Work by Nietschmann (20) in Nicaragua, although very
limited, supports a concept of strong site fixity and good homing
ability on the foraging ground. One hawksbill released several times
8 miles (12.9 km) from the capture site was taken the next day at the
same coral head in the same coral reef from which it was taken the
preceding day. The few recoveries from nesting beaches indicated that
the foraging population originated from several nesting grounds.
PERIODICITY:
The species is a nocturnal nester and a diurnal feeder according
to Witzell (08). Apparently nothing has been published on the
activity of the species in Florida. Tagging has been so limited that
little confidence can be placed in the results. In general, it is
stated that they renest during a season every 18 to 20 days. The
number of renestings are variable. In Costa Rica, they nest an
average of two times a season (08) and most nest every third year.
MIGRATION PATTERNS:
Some of the population is migratory, e.g., hawksbills tagged in
Costa Rica have been recovered on foraging grounds in Nicaragua (08).
Two turtles tagged in Nicaragua were recovered on nearby nesting
beaches (20). There is no published information on the migratory
patterns of the small Floridian population.
COVER/SHELTER REQUIREMENTS:
In general, the species requires reefs. Most are found on coral
reefs, but rock reefs will serve as a habitat (08,15). Carr (01)
reported that the species also occupied shallow bays and lagoons. In
Florida it is more common in the reef habitat (11).
The reef should be shallow; no maximum depth is found in the
Life History - 1 (DRAFT) - Life History
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
literature but Carr reported it on reefs at depths of 98.5 ft (30 m)
off Costa Rica. According to Causey (11) it is most abundant on the
Atlantic side of the Florida Keys in water of less than 16.5 ft.
(5 m). Depth may change with size, but this is not discussed in the
literature on the species.
The hatchlings are pelagic and it is postulated that in the
western Gulf of Mexico they passively float with blooms of the
bluegreen algae, Trichodesmium (15). In Florida one young hawksbill
washed ashore in the sargassum and had eaten sargassum (15).
REPRODUCTIVE SITE REQUIREMENTS:
The species selects a wide variety of beach types for nesting.
It is often a solitary nester on lagoon shores (21), or it can nest
on high energy beaches. The species usually nests at the rear of the
beach platform in the vegetation (08,22). On Mona Island, PR, nesting
occurred beneath overhanging brush, mainly guitaran (Suriana maritima)
or seagrape (Coccoloba uvifera) at the upper edges of sand beach along
the shore (31).
Mating has been described for other areas as occurring off the
nesting beach (21).
REPRODUCTIVE CHARACTERISTICS:
Witzell (08) summarized the information on mating and concluded
that mating occurs near the nesting beach. The males are very active
and may even pursue the females to the beach. He suspects a
polyandrous breeding behavior because several males show an interest
in the same female. Age at maturity and minimum and maximum breeding
ages are unknown; an old figure of 3 to 4 years was based on captive
specimens and an erroneous concept of size at maturity (23).
The hawksbill is a diffuse nester (33), i.e., it nests singly or
in small groups on pocket beaches. Mass nesting can occur, e.g.,
small concentrations of hawksbills still nest near Carmen, Mexico
(24).
In the Gulf of Mexico the nesting season is normally from May to
August (24), but the species may nest in any month of the year. There
is a record for Soldier's Key, FL, for October (25). The number of
nests made in a season is variable - 1 to 4 nests with the average
less than two in Costa Rica (17). The number of eggs per clutch is
also variable from region to region, e.g., Meylan (17) gives an
average clutch size of 142 for the Virgin Islands, 161 for Tortuguero,
Costa Rica and 101 for the Grenadines. The incubation time ranges
from 43 to 90 days throughout its nesting range (08).
PARENTAL CARE:
No parental care occurs. The eggs are deposited in the sand and
the female leaves the area (01).
POPULATION BIOLOGY:
The population in the waters of the continental U.S. is so
depleted that it can be assumed that there is adequate food and cover.
No estimates of population are available other than an estimated 2
nesters per year in Florida (08). Too few data are available for
anything except speculation about the present population of hawksbills
Life History - 2 (DRAFT) - Life History
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
in Florida. The depletion of the population by over exploitation is
hardly subject to dispute (01,05,26). Hendrickson (27) suggests that
recovery should be rapid once predation by man is completely removed
because the species can nest in a wide range of habitats, i.e., pocket
beaches of different types, and it can be a solitary nester or nest
in groups. Primary U.S. habitat is southern Florida, Virgin Islands,
and Puerto Rico.
In Micronesia one study reported hatching success rates of 53.6
percent and 29.1 percent (32).
SPECIES INTERRELATIONSHIPS:
Throughout the Caribbean, coral reefs provide the primary habitat
for this species (08,15,17). This interrelationship has never been
studied. The selection of reefs may be governed by availability of
cavities for hiding and the presence of favorite foods, particularly
sponges (17).
OTHER LIFE HISTORY DESCRIPTORS:
The role of temperature in determining the sex of sea turtle
offspring has received much attention in recent years. There is a
single paper on the hawksbill. The eggs laid in late October on
Soldier Key produced all males (25). If nests are transplanted, the
incubation temperature must be controlled in order to obtain favorable
sex ratios.
Life History - 3 (DRAFT) - Management Practices
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Controlling/Restricting Boating Activities
Beneficial Controlling/Restricting Off-Road Vehicles
Beneficial Restricting/regulating human disturbance of populations
Beneficial Controlling/Restricting Mining
Beneficial Reducing Urban Light Radiation
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Restricting/regulating human use of habitats
Beneficial Controlling pollution [thermal, chemical, physical]
Beneficial Restricting Poaching
Beneficial Controlling/Restricting Noncommercial Harvest
Beneficial Regulating commercial harvest levels
Beneficial Controlling/Removing Exotic Vertebrates
Beneficial Controlling/Removing Feral Animals
Adverse Subsistence Hunting/Fishing/Trapping
Existing Subsistence Hunting/Fishing/Trapping
Adverse Incidental Capturing/Killing
Existing Incidental Capturing/Killing
Adverse Commercial Exploitation
Existing Commercial Exploitation
Adverse
Existing
Adverse Predation
Existing Predation
Adverse Recreational development
Existing Recreational development
Adverse Shoreline modification/development
Existing Shoreline modification/development
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
COMMENTS ON MANAGEMENT PRACTICES -
The hawksbill sea turtle's chief contribution to commerce is
tortoise shell -- the translucent scutes which bring a high price on
the world market. In addition, the juveniles are stuffed for the
tourist trade, and the meat and eggs are eaten. On a world-wide basis
the international trade in tortoise shell is decimating the population
(05). In the United States a flourishing population existed only in
the reef area of southern Florida, and whatever the historical size of
this poulation may have been it was reduced to a few scattered
individuals before the start of the twentieth century (06,07). One is
left with the impression that exploitation alone could account for the
present status of the population (05). However, habitat alteration
and destruction has played a role elsewhere and certainly harbor and
beach development will hinder recovery (06,08,09). A small number of
hawksbills are part of the incidental catch of other fisheries (08,
10). The species is impacted by flooding of nests by storm surges and
unusual winter cold (09). The hawksbill is also limited in the
continental United States by the shortage of good habitat. The
Management Practices - 1 (DRAFT) - Management Practices
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
species favors reefs (hard substrate) apparently under 98.5 ft (30 m)
in depth (07).
Bright urban lighting can be detrimental to hatchling hawksbill
sea turtles (28,29). In St. Croix, VI, hatchlings were disoriented by
baseball stadium lights near the nesting beach. Several neonates were
killed crossing a road as they headed toward the lights (28).
The primary threat to hawksbills on Mona Island, PR, comes from
feral pigs (Sus scrofa) rooting up nests and eating the eggs. In many
areas 100% of a clutch had been consumed by pigs. Other sources of
mortality in Puerto Rico are from feral cats (Felis catus) and rats
(Rattus sp.) preying on neonates as they head toward the ocean, human
hunting of juveniles and adults, and light disturbance causing
disorientation (29).
In Palau, the major threat to the species comes from illegal take
of turtle eggs by local people (30).
APPROVED PLAN:
National Marine Fisheries Service. 1984. Recovery Plan for Marine
Turtles. National Marine Fisheries Service, St. Petersburg, FL.
355 pp.
The hawksbill sea turtle is included in the Recovery Plan for
marine turtles.
The primary objective for the recovery of the hawksbill sea
turtle, Eretmochelys imbricata, is to restore and maintain populations
commensurate with existing habitat. This requires that the following
information be collected:
1. The amount of existing habitat in terms of feeding areas and/or
nesting areas;
2. The carrying capacity of the habitat; and
3. Population estimates that indicate the relationship of
populations to the habitat.
Efforts to attain the primary objective fall into four major
categories as follows:
1. Mitigate factors affecting terrestrial mortality and/or stress.
a. Manage and maintain natural nesting beaches by monitoring the
extent of entrapment and erosion.
b. Inform and educate tourists, other potential buyers of shells
and/or stuffed juveniles (curios), and beach users. Public
education may involve brochures, posters, posted signs
identifying threats to the species, and conservation efforts
and prohibited acts (e.g., off-road vehicle use on nesting
beaches), in an effort to reduce human disturbance of nests.
c. Control lighting on nesting beaches and beach development.
(Although not specified in the Recovery Plan, the use of
easements cooperative agreements, land use zoning, etc., to
accomplish this task is recommended.)
d. Protect hatchlings during emergence especially from predators
(e.g., feral dogs, cats, rats, etc.).
Management Practices - 2 (DRAFT) - Management Practices
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
e. Provide active law enforcement to protect eggs and adults
from illegal take within U.S. jurisdiction. Adults are
subject primarily to commercial take, while both eggs and
adults are subject to subsistence take.
f. Promote legal protection throughout the range of the species.
The econimic value of its shell is such that controlling
commercialization in foreign countries will be very
difficult.
2. Assess and monitor population levels on nesting beaches.
a. Determine hatching success.
b. Tag or mark females.
c. Count and search for nests by air and ground.
d. Estimate avialable neting habitat by analyzing available data
and initiating new data gathering methodologies.
3. Mitigate factors affecting marine mortality and/or stress.
a. Monitor coastal processes of Critical Habitat (Lateral sand
movement, etc.) to allow prediction of time necessary for
beach rebuilding after destructive effects of sand mining
and hurricanes.
b. Regulate spoil dumping, sea floor mining, trawler tows (use
of TED - trawling efficiency device), and oil spills.
Prohibit use of explosives for fishing. Prepare a
contingency plan between sea turtle programs and plans
prepared by local industries.
c. Regulate methods, gear, areas and seasons of the commercial
fishing industry in U.S. and foreign waters.
d. Investigate and monitor occurrences of mortality from
entrainment and entrapment.
e. Regulate boat speed to decrease mortality from collisions.
4. Assess and monitor marine populations.
a. Determine need to monitor strandings.
b. Determine need to monitor incidental captures.
c. Determine feasibility of aerial and other means of at-sea
monitoring.
Ongoing recovery actions include beach and nest protection and
international efforts to stop commerce of hawksbill products.
Management Practices - 3 (DRAFT) - References
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
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Date 14 MAR 96
vanishing species: The hawksbill. Nat. Geog. Soc. Res. Rep.
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costas de Campeche, Mexico. Thesis, UABC, Escuela Superior de
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25 Dalrymple, G.H., J.C. Hampp, and D.J. Wellins. 1985. Male-biased
sex ratio in a cold nest of a hawksbill sea turtle (Eretmochelys
imbricata). J. Herpetol. 19(1):158-159.
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27 Hendrickson, J.R. 1982. Nesting behaviour of sea turtles with
emphasis on physical and behavioural determinants of nesting
success or failure. Pages 53-57. IN: Biology and conservation of
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28 Philibosian, R. 1976. Disorientation of hawksbill turtle
hatchlings, Eretmochelys imbricata, by stadium lights. Copeia
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29 Greenwalt, L.A. Jan. 6, 1978. [Memo to Regional Director, Rgn 4]
Biological opinion - Sec. 7 and impact of FWS project P-R W-9 or
Mona Is., PR on proposed threatened Mona boa, Mona ground iguana,
and Mona blind snake (and hawksbill sea turtle). On file at: U.S.
Fish & Wildl. Serv., Off. Endang. Sp., Washington, D.C. 20240.
30 Anon. July 25, 1983. Japan grant and cooperation project
information sheet. On file at: U.S. Fish and Wildl. Serv., Div.
Endang. Sp. & Hab. Conserv., Washington, D.C. 20240.
31 Thurston, J. and T.A. Wiewandt. [n.d.] Appendix I: Management of
sea turtles on Mona Island. Unpubl. Rep. on file at: U.S. Fish
and Wildl. Serv., Off. Endang. Sp., Wash., D.C. 20240. 13+ pp.
32 Anon. 1981. Report on basic research in technical cooperation
concerning experimental farming of the hawksbill turtle
(Eretmochelys imbricata) in Micronesian waters. Japan Tortoise
Shell Assoc., Nagasaki, Japan. On file: U.S. Fish & Wildl. Serv.,
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33 Meylan, A.B. 1982. Sea turtle migration - evidence from tag
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***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Witzell, W.N. 1983. Synopsis of biological data on the hawksbill
References - 2 (DRAFT) - References
Species TURTLE, SEA, HAWKSBILL
Species Id ESIS152003
Date 14 MAR 96
tutle Eretmochelys imbricata (linnaeus, 1766). FAO, Fisheries
Synopsis No. 137.
02 Meylan, A.B. 1982. Sea turtle migration - evidence from tag
returns. Pages 91-108. IN: Biology and conservation of sea
turtles. K.A. Bjorndal, ed. Smithsonian Inst., Washington, D.C.
03 Mauricio, G.A. 1982. Algunos aspectos de la proteccion de la
tortuga de carey, Eretmochelys imbricata (Linnaeus, 1766) en las
costas de Campeche, Mexico. Thesis, UABC, Escuela Superior de
Ciencias Marinas, Ensenada, Mexico.
04 Rebel, T. 1974. Sea turtles and the turtle industry of the West
Indies, Florida and the Gulf of Mexico. Univ. of Miami Press,
Coral Gables, FL.
05 Schroeder, W.C. 1924. Fisheries of Key West and the clam industry
of southern Florida. Appendix XII to the report of the U.S.
Commissioner of Fisheries for 1923, Washington.
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07 Carr, A.F., A. Meylan, J. Mortimer, K. Bjorndal, and T. Carr.
1982. Surveys of sea turtle populations and habitats in the
Western Atlantic. NOAA Tech. Memorandum, NMFS-SEFC-91.
08 Dalrymple, G.H., J.C. Hampp, and D.J. Wellins. 1985. Male-biased
sex ratio in a cold nest of a hawksbill sea turtle (Eretmochelys
imbricata). J. Herpetol. 19(1):158-159.
09 Groombridge, B. (compiler). 1982. Eretmochelys imbricata. IN:
The IUCN Amphibia-Reptilia red data book. Part I, Testudines,
Crocodylia, Rhynchocephalia.
10 Hildebrand, H.H. 1983. Random notes on sea turtles in the western
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12 Amos, T. April, 1985. Personal communication. Univ. of Texas,
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14 Causey, B. April, 1985. Supt. Looie Key Marine Sanctuary, FL.
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19 McMurtray, J. and J. Irwin. 1983. 1982 sea turtle project: Final
References - 3 (DRAFT) - References
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Species Id ESIS152003
Date 14 MAR 96
report Canaveral National Seashore. Nat'l Park Serv. Coop. Unit,
Inst. of Ecol., Univ. of GA (Athens). CPSU Tech. Rep. 4. 14 pp.
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21 Thurston, J. and T.A. Wiewandt. [n.d.] Appendix I: Management of
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22 Carr, T. 1978. A survey of marine turtles at Vieques Island.
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Conserv., Wash., D.C. 20240. 8+ pp.
23 Anon. 1981. Report on basic research in technical cooperation
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(Eretmochelys imbricata) in Micronesian waters. Japan Tortoise
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24 Calvo, P.M., Govenor, Territory of Guam. May 1981. [Letter to
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and Mona blind snake (and hawksbill sea turtle). On file: U.S.
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References - 4