Named for its smooth, leathery skin, the leatherback has graced ocean waters from the tropics to the Arctic since the time of the dinosaurs more than 100 million years ago. But scientists have documented a precipitous decline of the Pacific leatherback in the past two decades. Since 1982, their numbers have dropped from approximately 115,000 reproductive females to fewer than 3,000 remaining today, a decline of 97 percent.
"On land, the canary in the coal mine warns humans of impending environmental danger," said Roderic Mast, Conservation International Vice President and President of the International Sea Turtle Society. "Sea turtles act as our warning mechanism for the health of the ocean, and what they're telling us is quite alarming. Their plummeting numbers are, unfortunately, symptomatic of the ocean as a whole."
Although the leatherback may be the world's best-known sea turtle, five of the other six sea turtle species are also at risk of extinction. The Kemp's ridley and hawksbill turtles are classified by the IUCN Red List as Critically Endangered, as is the leatherback. The green, olive ridley and loggerhead turtles are all considered Endangered. The flatback turtle, found solely on the northern coast of Australia, is regarded as Data Deficient.
Sea turtles face threats ranging from destructive fishing practices such as long-lining and the poaching of turtle eggs, which some cultures regard as a delicacy. Long-lining is a practice in which ships extend up to 90 miles of fishing line with as many as 8,000 hooks, many of which unintentionally capture and kill sea turtles instead of their intended targets of fish.
"The Pacific leatherbacks currently face an annual mortality rate of up to 30 percent," said James R. Spotila, Drexel University Professor of Environmental Science. "That rate is clearly unsustainable, and without dramatic intervention, we can expect to see them disappear in as soon as a decade."
Scientists say that a two-pronged approach is necessary in order to reverse the rapid population decline of sea turtles:
* Nesting beaches require stronger protections and more careful management. Uncontrolled beachfront development and the poaching of eggs are threats to their survival. Lights on land present another threat, since turtles confuse them for the moon and walk toward them, leaving them stranded and unable to return to the ocean. Stronger protections to beaches in St. Croix and South Africa, for example, have allowed leatherback populations to begin rebounding.
* The ocean needs greater levels of protection and the fishing industry needs to employ new and safer techniques. Currently, less than one-half of one percent of the ocean enjoys formal protection. Fishermen targeting fish species often unintentionally kill sea turtles as "by-catch." Small and inexpensive changes to fishing techniques, such as slightly larger hooks and traps from which sea turtles can escape, can dramatically cut the mortality rate.
