The critically endangered leatherback is the largest living turtle in the world, and as the last surviving member of its family, the leatherback turtle has several distinguishing characteristics that differentiate it from other sea turtles. It is the only sea turtle that lacks a hard shell. Instead, the carapace of the leatherback is covered by oily flesh and its namesake thick leathery skin.
Adult leatherbacks average 3 to 6 feet long and weigh 500 to 1500 pounds. The largest specimen on record was 10 feet long, 8 feet wide and weighed almost 2,000 pounds. These unique creatures are capable of diving to depths of 5,000 feet and swimming at speeds of 20 mph. A leatherback equipped with transmitter backpack journeyed over 12,000 miles across the Pacific Ocean in 647 days, the longest recorded migration of any sea vertebrate. Unfortunately, satellite evidence suggests that it subsequently may have been captured at sea and brought aboard a vessel, a plight which continues to contribute to the decimation of the leatherback turtle population.
Leatherbacks are the longest-living marine species to ever ply the world's oceans. They have survived catastrophic asteroid impacts, outlived dinosaurs and witnessed the rise of humanity... but they are now on the brink of extinction, and scientists question whether they will survive the next decade. The population of leatherbacks may have declined by as much as 95 percent in the past two decades, and they have disappeared completely from many historically important nesting areas.
In the 1970s and 1980s, organized egg harvesting practically eliminated the viability of any leatherback nests producing turtle hatchlings in Costa Rica. Eggs were drank by locals with shots of alcohol, sold to commercial bakeries, and later exported to Asia as a delicasy. The early conservation efforts of Louis Wilson, owner of Hotel Las Tortugas, initially raised the awareness of the Costa Rican government. And in an effort to finally end poaching, scientists Dr. Frank Paladino of Indiana-Purdue University and Dr. James Spotila of Drexel University initiated the Las Baulas Conservation Project in 1988. The Las Baulas National Park (Parque Nacional Marino Las Baulas) was created by the government of Costa Rica in response to the resultant data on declines in leatherback populations in Playa Grande.
Las Baulas National Park, which is comprised of Playa Grande, Playa Ventanas and Playa Langosta, is one of the world's few remaining sites of significant leatherback turtle nesting activity and is critical to the survival of the Pacific leatherback turtle. Playa Grande supports the largest nesting colony of leatherback turtles in the Pacific Ocean. Close to 1,400 female leatherbacks nested at Playa Grande in 1990. By 2000 the number of females at Playa Grande were reduced to a few hundred, and last year and this year we have had less than 100 females come ashore. Individual female leatherbacks nest several times during the October-to-February nesting season, and lay clutches of 80-100 eggs per nest. Hatchlings emerge 60-65 days later. Today, park guards and conservationists work in concert to protect and monitor the activitiy of leatherback turtles in the park. See the Leatherback.org 2007-2008 Field Report for an update of activity this season, and visit the Earthwatch Institute to see how you can help.
Although poaching has subsided in Playa Grande, sea turtles in the Pacific and elsewhere continue to face an unsustainable rate of adult mortality as a result of commercial fishing techniques using gill nets and longlines. A 2003 study tracking tagged sea turtles by satellite estimated that up to one in three turtles are unintentionally killed at the hands of fishermen each year. Another study suggested that longline and gill net fisheries killed as many as 1,500 leatherbacks each year in the Pacific during the 1990s. Additionally, the harvesting of sea turtle eggs is still practiced elsewhere in the world, and in particular Asia where the turtle is pratically locally extinct in Malaysia and Thailand.
If you are visiting Playa Grande during the October-to-February nesting season, don't miss the opportunity to see this amazing creature as it comes ashore to nest as it has been for over 100 million years. Visit the office of Las Baulas National Park to sign up for a guided tour. And PLEASE stay off the beaches from dusk to dawn. During the daylight hours, be aware as you walk to avoid stepping on newly nested clutches or marked nests. Remember... this is nature, nests are usually above the high tide line, but can be anywhere and are often unmarked or simply marked with a stick.
Sources for this article include Wikipedia, and the following articles in National Geographic News: Endangered Turtle Makes Record 647-Day Journey, Leatherback Turtles Near Extinction, Leatherback Sea Turtle Mating Filmed for First Time.