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Wildlife Spotlight: Leatherback Turtle (Derrmochelys Coriacea)
The Ancient Sea Traveler
By Stefan Marti
Last month, on a bird watching boat trip to the Cordell Bank, viewers were treated to a rare and wonderful sight. A few feet from the starboard bow of the ship, a giant leatherback turtle surfaced.
The leatherback is the largest turtle in the world, and can measure 6 to 8 feet long and weigh up to 2000 pounds (900 kg). They are usually spotted in warmer waters—the Caribbean, the mid Atlantic between West Africa and South America—however, they can travel as far north as Newfoundland and British Columbia. During the summer, they occasionally migrate past the Farallon Islands and Cordell Bank. Leatherbacks are pelagic animals, spending most of their time in the open ocean, but they also forage into coastal waters.
Unlike other sea turtles, which have hard, bony shells, leatherbacks have a soft, rubbery carapace with oil-saturated connective tissue overlaying loosely interlocking dermal bones. Their carapace is 1-2 inches thick and has seven longitudinal ridges that taper to a blunt point. Adult turtles are predominantly black with a pinkish white mottled ventral surface and pale white and pink spotting on the top of the head. Their front flippers are extremely long and lack claws and scales, enabling them to swim great distances. Turtles tagged in Nova Scotia have been tracked as far away as Panama and northwest Africa.
Leatherbacks have pointed tooth-like cusps and sharp-edged jaws that are designed to eat soft-bodied prey like jellyfish and tunicates. Unfortunately, with the rise of plastic waste in the oceans, hundreds of leatherbacks choke each year on clear bags, mistaking them for jellies. Many leatherbacks are also caught in fishing nets, trawls and dredges.
However, the greatest danger to their survival is still the illegal harvesting of their eggs and meat. Females nest several times a season on open sandy beaches, and though they are an endangered species, poaching continues. Global nesting populations have dropped in half since1980. The Pacific coast of Mexico was once their largest nesting population (with 65 percent of the worldwide population). Today, due to harvesting and human development on the sandy shores, it is home to only one percent of its 1980 numbers. Now the largest nesting areas occur in the western Atlantic in French Guiana and Colombia. In the United States, small nesting populations occur on the east coast of Florida.
Diving deeper than any other turtle, leatherbacks have been recorded at 3900 feet below the ocean’s surface. They can stay warm because of thermoregulatory adaptations such as a counter-current heat exchange system, high oil content, and large body size. This allows them to migrate thousands of miles each year into colder waters, and during the summer, with a little luck, you may spot one off the coast of California.
For more information, visit http://www.nmfs.noaa.gov/pr/species/turtles/leatherback.htm.
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