Sea Turtles of the Atlantic and Gulf Coasts of the United States

Leatherback

Leatherback Dermochelys coriacea Dermochelyidae Status National: Endangered. International: Critically Endangered. Leatherbacks, because of their extensive migrations and specialized food requirements, are often seen in loose groups, usually well offshore. Sometimes more than a dozen may be observed in a small area. Depending on whether they are feeding on surface-floating jellyfish or those found at great depths, leatherback sightings may be frequent or rare. In short, accurate population counts are difficult, but summer migration numbers along the northeastern coast are estimated to be in the low thousands. Such numbers are probably present at times off the southeastern coasts as well, and also in the Gulf of Mexico. Several hundred leatherbacks regularly nest on the Florida east coast, and at least one has nested as far north as Maryland, but most leatherbacks nest in tropical areas well outside the continental United States. Some tagged animals found dead on eastern U.S. shores were originally tagged in Central and South America, so it is clear that multinational protection is required if their status is to improve. Distribution and Habitats Of all the reptiles in the world, this species has the greatest geographic range. Leatherbacks are mainly tropical nesters. Major nesting areas (with more than one thousand females) are found on the Caribbean, Central and South American, and west and southwest African coasts, but a minor amount of nesting occurs in Florida. The foraging range of leatherbacks includes the Atlantic, Pacific, and Indian oceans north and south toward the Arctic and Antarctic circles. 36 leatherback Their physiological adaptations to cold water and great depths along with their powerful swimming abilities allow leatherbacks to wander great stretches of ocean. Aerial surveys have confirmed that some individuals may be found west of the Gulf Stream throughout much of the year. Although leatherbacks have been described as the most oceanic or pelagic of all the turtles, they may spend time foraging relatively close to shore in search of the jellyfish on which they feed. Surveys have shown almost no leatherbacks in the Gulf Stream, but groups of migrating individuals are observed in continental shelf waters in spring and fall each year; most of these are not from Florida populations. Each spring, some leatherbacks migrate north along the Gulf and Atlantic shores to locations with dense aggregations of large jellyfish. By late May leatherbacks are less common in the waters off the Southeast, but in some years individuals may be observed in the summer months. These may be females that nested on tropical beaches and were late heading north, as suggested by a stranded (dead) female examined in late summer in Rhode Island. In autumn the migration direction is reversed, and leatherbacks are sometimes seen in groups in the Gulf of Mexico. Migration routes in the Atlantic Ocean are apparently not restricted to well-defined corridors as they are in the Pacific Ocean. Leatherbacks spend all of their juvenile years in the open ocean (in conmajor nesting general distribution Leatherback (Dermochelys coriacea) top A female leatherback comes ashore. Courtesy of Alejandro Fallabrino. middle A female leatherback after nesting. Courtesy of Richard Moore. left A closeup of leatherback skin. Photo by Carol Ruckdeschel. 38 leatherback trast, large juvenile cheloniids return to inshore marine waters to complete their development). Essentially nothing is known of leatherback behavior from the time they enter the water as hatchlings until they near adulthood, thereby presenting one of the remaining mysteries of sea turtle biology. Appearance By far the largest living turtle, the leatherback is the easiest sea turtle to identify because of its ridged, black, skin-covered shell; deeply notched, double-cusped upper jaw; and immense size. In addition, many internal features make this species unusual among turtles and contribute to leatherbacks ’ amazing ability to exploit the oceans and feed on a variety of softbodied organisms, sometimes in very cold and deep waters. Size Most adults reach a weight of 400–450 kilograms (900–1,000 pounds, approximately half a ton). The record size is a little over 780 kilograms (2,000 pounds). Other than hatchlings, individuals that weigh less than 125 kilograms (275 pounds) are rarely seen. About a dozen juvenile specimens less than a meter in length are known, and ten of those were found in waters The leatherback (right) is by far the largest living turtle. Note how much smaller the green sea turtle (above) is in relation to the humans. Courtesy of Asaf Senol and Suzanne Livingstone...