PLAYA GRANDE, Costa Rica - The leatherback sea turtle, the massive and mysterious reptile of the Pacific Ocean, has outlived the dinosaurs by 65 million years. It has survived fiery asteroid strikes and ice ages that chilled the globe.

But it doesn't look as if this prehistoric innocent will survive us.

Beset by poachers on land and snared in fishing gear at sea, the Pacific Ocean's population of leatherbacks has plunged 95 percent in the last 22 years, scientists say.

They estimate that fewer than 5,000 nesting females remain in the Pacific.

"I never thought this ancient creature would be vulnerable to extinction," said Larry Crowder of the Duke University Marine Lab. "Unless something changes, the Pacific leatherback will be extinct within 10 to 30 years."

Greater menace

Scientists, once focused on protecting turtle nests on shore, are shifting their attention to what they see as a greater menace: the drowning of turtles in fishing nets and on strings of baited hooks unfurled for 50 miles off the sterns of commercial long-line vessels.

Crowder calculates that long-line fishermen set 4.5 million hooks every night, stringing the ocean with the marine equivalent of 100,000 miles of barbed-wire fencing.

Alarmed by the precipitous decline of leatherbacks, more than 400 scientists recently called on the United Nations to ban coastal drift nets and pelagic long-lining for swordfish until the gear can be modified to reduce turtle deaths.

The United Nations has yet to take up the cause, which is certain to stir opposition from the fishing industry.

Fishermen insist that they don't target sea turtles, that the air breathers are inadvertently caught in nets or snagged by hooks and then drown when they cannot reach the surface to breathe.

Scientists and conservationists are pushing hard to reduce wasteful practices in commercial fishing fleets, which besides drowning turtles, inadvertently catch and kill seabirds, dolphins, sharks, marlin and many other types of fish that are discarded.

They also see the looming demise of the Pacific leatherback as a warning sign that the world's largest ocean is in trouble.

Leatherbacks range so widely and are so dispersed in the Pacific that scientists never previously considered their population capable of collapse.

Limits to marine life

Now they realize that the vast Pacific has limits and that its marine life has limited resilience and is proving no match for burgeoning international fishing fleets.

"The Pacific is the Wild West: It's way overfished by these huge fleets, especially from Asia, and there are no regulations at all," said Frank V. Paladino, chairman of the biology department at Indiana-Purdue University.

"I keep trying to stress, it's not just sea turtles. Everything is going in the Pacific. Sharks. Dolphins. Billfish. The leatherbacks are just first to go."

Aside from lobbying for changes in global fishing practices, Paladino and other turtle researchers follow female turtles, gathering up their eggs as they are laid and reburying them in safer parts of the beach.

Paladino and James V. Spotila, a zoologist at Drexel University, pay rangers at Las Baulas National Park to protect the turtles from poachers by patrolling the beach here on Costa Rica's Pacific shoreline from dusk to dawn.

Using grants, donations and tourism dollars, they also run a leatherback hatchery to boost the remnant turtle population.

Only one in 1,000 hatchlings makes it to adulthood. They figure they can improve the odds to 1 in 100 by incubating the eggs in the hatchery and fending off predators such as raccoons, skunks and dogs.

"We never intended to do all this," Spotila said. "But you study this magnificent animal and you see it going extinct, if you don't step in and do something. It's like the kid walking by the dike with a leak in it. You stick your finger in it. Then you cannot very well leave."

The leatherback, the largest and oldest of the sea turtles, has been around 100 million years or so -- surviving the asteroid that 65 million years ago struck the Yucatan Peninsula, which scientists believe contributed to the extinction of the dinosaurs.

Leatherbacks, though contemporaries of the dinosaurs, are reptiles and feed predominantly on another ancient creature: jellyfish.

The turtle gets its name from a leathery shell that has the texture of smooth, hard rubber. Its shell also has hydrodynamic dorsal ridges, which, combined with front flippers that can span 10 to 15 feet, enable these reptiles to soar like giant birds through the ocean.

Paladino and Spotila have been studying nesting leatherbacks in Costa Rica since the 1980s.

In 1988, they tallied 1,367 turtles nesting on Playa Grande, one of the four largest nesting colonies in the world. By 1995, the number had dropped to 506. This year, it was only 59, and they predict the colony could vanish altogether within a decade or so.

Sizing up threats

Initially, scientists figured the biggest threats came from poachers who slaughtered turtles for their meat or stole the eggs to be sold for reputed aphrodisiac qualities.

Scientists supported the ban on harvesting of turtles and their eggs, and then pursued the trickier task of enforcing the law in poor countries.

Then turtle researchers started charting the remarkable range of leatherbacks with satellite tracking tags.

They soon discovered that the leatherbacks in Mexico and Costa Rica swam south around the Galapagos Islands and into the drift nets positioned by fishermen like enormous fences off the coast of Peru and Chile.

"The satellite tags gave us an inkling that the problem wasn't just on the beaches, but on the high seas," said Scott Eckert, a San Diego-based sea turtle researcher.

He calculates that these gill nets, designed to catch swordfish, killed between 2,000 and 3,000 leatherbacks every year from 1982 to the mid-1990s.

The United Nations has since banned gill nets more than one mile long in international waters, but smaller ones continue to snag turtles.

In the global hunt for swordfish, mahi-mahi and shark fins (for shark fin soup), most of the nets have now been replaced by long-line fishing.

More boats from China, Taiwan, Korea, Japan and Spain join the Pacific long-line fleet every year, each unfurling lines of baited hooks of at least 50 miles.

Leatherbacks bite only occasionally at the hooks baited with squid. Mostly they get tangled in the lines or snag flippers on hooks and then drown.

To protect leatherbacks around Hawaii, the Turtle Island Restoration Network of Forest Knolls sued in federal court and shut down the U.S. swordfish long-line industry around the islands.

About 30 of the boats moved to Southern California to escape the ban, but conservationists filed another lawsuit to close those down too. The case is pending in federal court.

Scott Barrows, general manager of the Hawaii Longline Association, complains that the ban, instead of protecting turtles, simply created an opening for less cautious fishermen from Asia.

"They took us out and allowed the foreign fleet to come, catch the lucrative swordfish and catch and kill more turtles."

Although U.S. fishermen must take yearly classes on resuscitating federally protected endangered species such as the leatherback, he said, "The foreign fleet doesn't have a clue. Some of the turtles they catch would live if we caught them."


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