Of the six sea turtle species that are found in
US. waters or that nest on U.S. beaches, all
are designated as either threatened or
endangered under the Endangered Species
Act. Endangered status means a species is
considered in danger of extinction
throughout all or a significant portion of its
range; threatened means it is likely to
become endangered.

Six of the seven sea turtle species are listed
as endangered or threatened: green, Kemp's
ridley, olive ridley, hawksbill, loggerhead and
leatherback sea turtles. Only one species,
the flatback sea turtle, is not considered
threatened with extinction at this time.
Overharvest of eggs for food, intentional
killing of adults and immature turtles for
their shells and skin, and accidental
drowning in commercial fishing gear are
primarily responsible for the worldwide
decline in sea turtle populations. In addition,
coastal residential and resort development
has degraded nesting habitat, and pollution
of oceans threatens foraging habitat.

Sea turtles are among the largest living
reptiles. They have scales and a bony shell,
are cold-blooded, breathe air, and lay their
eggs on land. Sea turtles are long-lived,
although scientists are uncertain exactly
how long they live because there is no known
way to determine their age.

Unlike the land turtles from which they
evolved more than 150 million years ago, sea
turtles spend almost their entire lives in the
sea. They glide gracefully through the water
with flipper-like forelimbs and a streamlined
shell. Sea turtles frequently come to the
surface to breathe when active, but they can
remain underwater for several hours while
resting. Leatherbacks can dive to more than
8,000 feet below sea level.

Though most sea turtles live in warm
tropical and subtropical waters, leatherbacks
are the exception. They travel as far north as
Labrador, Canada, and Alaska and as far
south as the Cape of Good Hope in Africa
and southern New Zealand.

Adult green turtles are herbivores
(plant-eaters), while all other sea turtles are

sh & Wildlife Service

Sea Turtles

carnivores (meat-eaters) or omnivores
(plant and meat-eaters). Sea turtles do not
have teeth; instead, they use their powerful
jaws to tear and crush their food. Each
species prefers certain food items.

During the nesting season, which in the
continental United States occurs between
March and October, female sea turtles come
ashore to lay their eggs. Females excavate
pits using their fore and rear flippers to
remove the upper layer of dry sand. Then,
with their bodies in the pit, they use their
rear flippers to dig egg chambers in moist
sand. Females lay from 50 to 160 white eggs,
about the size of ping-pong balls, cover the
eggs with sand, and return to the water.

The eggs incubate for about 50 to 70 days
before hatching at night. The sea turtle
hatchlings make their way up through the
sand to the surface and then scurry toward
the water. Hatchlings spend several days
swimming offshore until they reach safety
within the protective masses of floating
seaweed in areas where ocean currents
meet. These areas, called driftlines, are
rich in food and provide hiding places that
conceal juvenile turtles from predators.
They drift there for a year or more until
they reach a certain size or age at which
time they return to nearshore waters.

As adults, female sea turtles return to the
same beaches where they hatched to lay
their eggs, often navigating across great
expanses of water.

Today there are still many threats to sea
turtles. Sea turtle nests can be destroyed by
natural events, such as tidal surges or
hurricanes, and the eggs can be lost to
predation by raccoons, ghost crabs, and
other animals. Although adult sea turtles
have few natural predators, sharks and
killer whales are known to prey on them.
Unlike land turtles, sea turtles cannot
protect themselves by pulling their head
inside their shell.

Human activity is the primary cause of the
decline in sea turtles. Modification to nesting
areas can have a devastating effect on sea
turtle populations. In many cases, prime sea
turtle nesting sites also are prime real

estate. If a nesting site has been disturbed
or destroyed, female turtles may nest in
inferior locations where the hatchlings are
less likely to survive, or they may not lay
any eggs at all.

Artificial lighting from developed beachfront
areas often disorients nesting females and
hatchling sea turtles, causing them to head
inland by mistake. This leaves them
vulnerable to predation, exhaustion,
desiccation ar being crushed by vehicles.
Adult females also may avoid brightly lit
areas that would otherwise provide suitable
nesting sites.

Beach driving is another major threat to
sea turtles. Headlights and movement of
vehicles on the beach at night can deter
female turtles from coming ashore to nest.
Often, vehicles collide with turtles at night.
Also, vehicles on the beach can leave tire
tracks in the sand deep enough to prevent
hatchlings from taking a direct route from
the beach to the ocean and leaving them
vulnerable to depredation, desiccation and
exhaustion. Vehicles running over nests may
harm egg development.

Activities in the open water also threaten sea
turtles. Sea turtles may become entrapped
in commercial fishing nets and shrimping
trawls and caught on hook and line fishing
gear. Although turtles can hold their breath
for long periods, stress and activity from
trying to escape from fishing gear shortens
this time and often results in death. Sea
turtles surfacing to breathe may be killed or
injured by ships, small boats and jet skis.

Commercial exploitation of sea turtles for
food and leather products has led to the
collapse of many populations. International
trade in sea turtle shells has been a major
factor in the decline of hawksbill populations
around the world. Between 1970 and 1989,
more than 1.2 million hawksbills were killed
for their shells, which are used to make
combs, brushes, jewelry and other
ornamental items.

Sea turtles often mistake balloons, plastic
pieces and other debris for food they
normally eat. Consuming this marine debris


can lead to nutritional problems and death.
Many sea turtles, particularly those in
Florida and Hawaii, are afflicted with a
disease called fibropapillomatosis. This
disease can cause large tumors on the
turtle’s skin, eyes and mouth, and sometimes
affects internal organs. Turtles with heavy
tumor burdens become debilitated and die.
Although the disease primarily affects green
turtles, it is emerging as a serious threat to
loggerheads and has heen documented in
several other sea turtle species as well.
Scientists believe that the environmental
alteration of sea turtle foraging habitat by
pollution and contaminants may also play a
role in this disease

The 1973 Convention on International Trade
in Endangered Species regulates the import
and export of endangered and threatened
species. More than 100 CITES member
nations pledged to monitor and reduce trade
in sea turtle products.

To protect sea turtles in the southeastern
United States, Congress established the
Archie Carr National Wildlife Refuge in
1989. Located on two barrier islands off

Florida’s eastern shore, the 500-acre refuge
includes more than 9 miles of beach. Large
numbers of loggerhead and green sea turtle
nests are laid in this area, and it also
provides nesting habitat for leatherbacks.

The U.S. Fish and Wildlife Service, with the
assistance of state conservation agencies,
educates beachfront property owners about
the threats to sea turtles and their nesting
sites and some communities now restrict or
prohibit beachfront lighting during sea
turtle nesting season.

Since many sea turtle species swim through
international waters and nest on beaches
outside the U.S., sea turtle conservation
requires global cooperation. For example,
Kemp’s ridleys and loggerheads often are
caught in shrimp trawls in the Gulf of
Mexico. Currently, U.S. and Mexican
regulations require all shrimpers to use
turtle excluder devices, which provide an
escape hatch for trapped turtles.

Cooperation between the U.S, Fish and
Wildlife Service, National Marine Fisheries
Service and the Mexican government now

protects the only major Kemp’s ridley
nesting site in the world. This beach is
located along the Gulf of Mexico near the
village of Rancho Nuevo. While nearly
40,000 female Kemp’s ridley sea turtles came
ashore on this beach in 1947, only 200 were
observed nesting by 1978. Today, because of
protection of nesting females and their nests
and the use of turtle exeluder devices in the
shrimp fisheries of both Mexico and the
United States, there are an estimated 1,500
nesting females.

Biologists once relied on tagging as a
means to determine where and how far sea
turtles migrate. Metal or plastic tags,
placed on a flipper or on the shell, included
instructions for reporting the date and
location of a sighting. Today, researchers
use satellite tracking devices to study
migration. Sea turtles are outfitted with a
small transmitter that sends a signal to a
satellite orbiting the earth. Computers on
board the satellite calculate the location of
the turtle and send the data back to the
earth for researchers to study.

Loggerhead turtle

The loggerhead turtle is the most abundant
nesting sea turtle in the southeastern U.S.
It is reddish brown to yellow in color and
has a large head. The adult loggerhead is
2% to 31% feet long and weighs 150 to 400
pounds. Loggerheads feed primarily on
mollusks and crustaceans,

Kemp’s ridley turtle

The Kemp’s ridley turtle, the rarest and
most endangered of all sea turtles, is also
the smallest with adults reaching 2 to

2% feet in length and weighing 80 to 100
pounds, The Kemp’s ridley has an oval shell
and is usually olive-gray in color Its diet
consists primarily of crabs. Untike most
other sea turtle species, the Kemp's ridley
nests primarily during the daytime.

Hawksbill turtle

The hawksbill turtle has a distinctive hawk-
like beak and a patterned top shell with
overlapping scales. As an adult, it may
reach up to 3 feet in length and weigh 100

to 200 pounds. It is able to climb over reef’s
and rocks to nest in beach vegetation. The
hawksbill feeds primarily on sponges and is
most often associated with the coral reef
community.

Green turtle

The green turtle can reach more than 3 feet
in length and weigh 300 to 400 pounds as an
adult. Though brownish in color, its name
comes from the greenish color of its fat,
called calipee, which was used to make turtle
soup. Hatchling green turtles eat a variety
of plants and animals, but adulis feed
almost exclusively on seagrasses and algae.

Leatherback turtle

The leatherback, at 4 to 8 feet in length and
700 to 2,000 pounds as an adult, is the
largest of the sea turtles. Its shell is
composed of a mosaic of small bones
covered by firm, rubbery skin with seven
longitudinal ridges or keels. Jellyfish are
the main staple of its diet.

US. Fish & Wildlife Service
http:/Awww.fws.gov
June 1998