Leatherbacks are threatened by beach development and long-line fishing.
Thursday, April 25, 2002
Most of us know the footage by heart. A female sea turtle struggles up a beach, laboriously digs a nest with her flippers, then drops her eggs into it one night while the camera crew shines bright lights on her nether regions. A scene or two later, while the hatchlings are flopping toward the ocean, the narrator tells us that few of them will survive their natural predators, that the nesting beaches are endangered and the sea turtle population is plummeting. It''s as familiar as any episode of M*A*S*H*.
The next Discovery Channel turtle show may be about leatherbacks. The largest of the sea turtles, the leatherback averages about six feet long and 1,100 lbs (the largest on record, a nine-foot male found in Wales, weighed in at a ton). As its name implies, it has no shell, just very tough skin on its back with ridges running the length of its body. It feeds almost exclusively on jellyfish and migrates huge distances to and from nesting sites in the tropics (satellite telemetry shows that most of the leatherbacks who forage in Monterey Bay nest near Malaysia).
The number of females returning to nesting sites to lay eggs-a good indicator of present as well as future populations-has dropped precipitously in the last 15 years, in some cases from thousands to dozens.
On Monday, a group of researchers and environmentalists from around the world convened in the Nautilus Room at Asilomar for four days of strategizing about how to save the leatherback. Among those present was Dr. Sylvia Earle, Chief Scientist for the National Oceanic and Atmospheric Administration under Clinton, and currently the National Geographic Society''s Explorer in Residence. Poised and sincere, Earle delivered a heartfelt keynote address.
"If people today could see a dinosaur, a brontosaurus maybe, what a smashing headline piece of news that would be!" she said. "Well, we''re talking about an animal that was here before the dinosaurs. They have seen so much change, and yet their future so much depends on what we do-or may not do-even in the next five years."
Turtles prefer to nest in undisturbed areas, and encroaching beach development discourages them. In Latin America their eggs are served up as aphrodisiac appetizers in bars.
Longline fishing is the other culprit. Typically used to catch migratory predator fish like swordfish and tuna, the multiple baited hooks also catch or entangle turtles. In the instance of one Atlantic longline fleet, the unwanted catch for the year almost equaled the intended catch in number. For unexplained reasons, the turtle "bycatch" with swordfish is dramatically worse than with tuna-10 times as much.
After the break, marine experts put forth their dismal findings concerning nesting. The most alarming data came from Laura Sarti Martinez, who has studied nesting leatherbacks on Mexican beaches since 1987. At one site, the number of nesting turtles has dropped from 5,000 in 1987 to just four last year. On one critical nesting beach in Costa Rica, the 1988 high of 1,367 leatherbacks fell to 68 in 2001.
Todd Steiner, executive director of the Sea Turtle Restoration Project and the conference organizer, considers longline fishing-which he says has "exploded" at the same time that the turtles'' population has plummeted-the most dire threat to leatherbacks. "You can protect thousands of eggs and only one will become an adult-those are just the natural odds," he says. "So if you put all your effort into that and then they get snagged on longlines, it does you no good."
But it''s not out of our control, he says. "I think Americans have a greater responsibility, because the reason there are all these people out there fishing is so we can have sushi."