Weighing in at up to 700 kilos in weight and two meters in length, leatherback turtles are the largest of all turtle species. The last remaining member of the genus, Dermochelys, leatherback turtles are so named for their soft shell or carapace. Their barrel-shaped body is propelled through the water at top speed by oversized fins that have been recorded to reach more than 270 centimeters in the largest specimens.
Leatherback turtles maintain an extremely high metabolic rate producing a heat-exchange function that makes it possible for them to maintain a body temperature as much as 18ºC above the surrounding water in cold environs. This unique adaptability is what has contributed to the leatherback’s survival in deference to environmental stress of the modern world.
Its unique adaptability has allowed the leatherback to survive in a broad ocean range from the cold northern climes of Alaska and Norway to warmer subtropical oceans at the Cape of Good Hope in Africa, the southernmost tip of New Zealand and the Mexico’s west coast. Scientists have determined minute genetic differences in the Dermochelys populations that prefer the colder northern climes, those that inhabit the warmer, temperate waters of the Western Pacific and a final subspecies in the Eastern Pacific.
The leatherback survives predominantly on a diet of jellyfish consumed in open ocean waters. Floating plastics and balloons from the human waste stream are frequently mistaken as jellyfish by the graceful giants feeding on a reducing food stream in increasingly polluted waters. The plastics bind in the turtle’s digestive tract and ultimately contribute to the demise of a once prolific species.
Modern fishing equipment, such as gill-nets, buoy anchor lines and long line fishing ropes and cables have also been documented for drowning mature Leatherbacks in the open seas.
As with other sea turtle species, Leatherbacks lay their eggs on soft, sandy beaches near their feeding grounds. Their soft shells are particularly prone to damage from sharp rocks and glasses that are another result of global pollution. In an effort to minimize injury generations have focused on beaches that have traditionally offered shallow approaches with gently lapping waves and shelter from storm-driven seas. These beaches are particularly prone to erosion, however, which has ultimately reduced suitable incubation habitat for their eggs.
Leatherback eggs have long been prized by native cultures and human predation of their eggs has further impacted the dwindling populations. Breeding females are estimated at about 100,000 worldwide, each laying about 100 eggs each year in the late winter to mid-summer months depending on the region. Hatchlings that escape consumption by humans and other predators must make a long dash to the sea under the watchful eye of seabirds and crustaceans, ever vigilant for an easy meal. Survival rates are undocumented, but are estimated to be extremely low.
Recent developments in conservation efforts have seen the development of legislation worldwide to protect Leatherbacks and other endangered turtle species. With diligence and a spirit of cooperation we can continue to impose changes in fishing regulations and environmental waste management that will help this dying species rebuild its population in our lifetime.
source: Leatherback Sea Turtles