Scientific
Name: Dermochelys coriacea 
Description: Adult leatherbacks are the largest turtles in the world, weighing an average of 660-1,210 pounds and measuring 53-69 inches. These turtles are generally black in appearance, with some gray and white spots (vermiculations) on the ventral (bottom) side of the body and dorsal (top) surface of the flippers. The 150 leatherbacks that have washed up dead on Georgia's beaches since 1982 have ranged in size from 10-74 inches with an average of 60 inches. Unlike other sea turtles, leatherbacks do not have large scutes covering the carapace and plastron; instead, they have a layer of skin over a very flexible shell. The carapace has seven raised longitudinal ridges. The most distinguishing morphological characteristics of leatherbacks are their large size and dark color. Two large cusps on the upper jaw can be seen upon close examination and are also distinctive. While swimming at the surface and breathing, the leatherback often holds its entire head out of the water and the dorsal surface of the back usually breaks the surface as well.
Range and Habitat: Leatherbacks are highly pelagic (live in the open sea) with a global distribution, perhaps more widely distributed than any other reptile on earth. Found throughout the Atlantic, Pacific, and Indian oceans, these turtles can tolerate cool northern hemisphere ocean temperatures, allowing them regularly to move farther north than other species of sea turtles. They have been found swimming in sub-Arctic regions, a reflection of their apparent ability to maintain core body temperatures higher than surrounding ambient ocean temperatures. Even though they are ocean wanderers, leatherbacks regularly approach the shore. They have been seen close to Georgia's barrier beaches and have even been observed swimming in the sounds and estuaries near Wassaw, Ossabaw, and St. Catherine's islands.
Diet: Primarily jellyfish, but occasionally other marine invertebrates like octopi and squid. Georgia turtles have been found engorged with cannonball jellyfish.
Life History: Leatherbacks, like other sea turtles, deposit eggs in the sand of warm tropical and subtropical beaches. Central and South American beaches support the majority of nesting in the Western Atlantic. Leatherbacks are found in Georgia waters primarily in the early spring, fall, and early winter during migration to and from the tropics. Georgia DNR researchers fly weekly aerial surveys in April and May to document leatherback abundance and minimize interactions with the shrimp trawl fishery. Dead leatherbacks that have been found on Georgia's beaches have been identified from tags and genetic samples as originating from the nesting beaches of St. Croix, Trinidad, and French Guiana.
Leatherbacks nest
regularly in the southeastern U.S., particularly in Florida.
Only ten nests have
been confirmed in Georgia, two of which were laid in 2003 on St.
Catherine's and Cumberland islands. Leatherbacks normally nest
about six times in a season but have been known to nest as many as
eleven times. Like
other sea turtles, leatherbacks do not nest every year but normally
return to nest every 2-4 years. The 80-90 billiard-ball size eggs
normally hatch in 50-78 days.
Very little is
known about leatherbacks during any of their developmental life
stages, and virtually
nothing is known of the post-hatching and juvenile life-stage
periods. Young
leatherbacks grow more rapidly than other sea turtles and probably
reach maturity at a much earlier stage as well. The average age of maturity
has been estimated at 13-14 years for females, which is quite rapid
compared to the estimated 20-30 years to maturity in loggerhead
turtles. Maximum life
span is not known.
Leatherbacks are one of the deepest diving air breathing animals, reaching depths of 3,300 feet. Sperm whales may be able to dive to three times that depth.
Threats/Comments: A recent estimate of the worlds nesting female population is 34.500 individuals, a mere third of the estimated world population two decades ago. The species appears to be in a worldwide population decline. Directed harvesting of adults and egg poaching probably contribute to this decline. Egg poaching in countries such as Costa Rica is a profit-oriented endeavor, where eggs are more likely to end up in bars as supposed aphrodisiacs than served as staple food items. In Malaysia, however, the subsistence harvest pressure on eggs has caused a complete collapse of what was once one of the largest concentrations of nesting leatherbacks in the world.
An equally
insidious threat to leatherbacks and all sea turtles, and one that
is very difficult to assess, is incidental mortality due to
commercial fishing efforts throughout the oceans. These ocean
wanderers are caught on hooks from commercial long-line fisheries,
and they become entangled in drift gillnets in the open ocean. An
estimated minimum of 1,000 leatherbacks are killed annually in the
Pacific as bycatch from commercial fisheries. Scientists predict the
pacific stock may be extinct within 30 years if drastic action is
not taken. In many
parts of the world, including Georgia, leatherbacks drown in shrimp
trawls. However,
Georgia now has regulations are now in place that require shrimp
fishermen to use Turtle Excluder Devices (TEDS) with openings large
enough to exclude adult leatherbacks. The adult turtles were too
large to fit through the older TEDS that were originally designed
to allow the much smaller Kemps ridley and loggerheads to
escape.
Biologists urge the public to assist in conserving leatherbacks and other sea turtles. Following are some tips:
- Never disturb a sea turtle that is crawling to or from the sea
- Once a sea turtle has begun nesting, observe her only from a distance. Do not crowd
- Never attempt to ride a sea turtle
- Do not shine lights in a sea turtles eyes or take flash photography
- Avoid or reduce beach lighting at night
- Do not disturb a turtle nest
Report all sightings to (478) 994-1438. To report a dead or injured turtle, or sea turtle harassment, call (800) 2-SAVE-ME (1-800-272-8363). If the sea turtle is tagged, please include the tag color and number in the report if possible.
Photo Credits: from top- Matthew Godfrey, Matthew Godfrey, Jacey Biery