Requiem for a Heavyweight | Science | Smithsonian

Requiem for a Heavyweight

Science meets shamanism at a gathering to ponder the fate of the Pacific Ocean leatherback

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The sorry state of the world’s most massive reptile attracted an impressive list of biologists, environmental advocates and what might be called unaffiliated lovers of nature to the International Leatherback Survival Conference, which turned out to be a curious mixture of science, politics and mysticism. The gathering took place this past spring at a conference center in Pacific Grove, California, near MontereyBay, whose chill waters attract the leatherbacks each year in late summer. Some turtles swim here from as far away as Samoa, crossing the Pacific Ocean in heroically straight lines. They come to eat jellyfish, although it may be that they migrate to Northern California for additional reasons. Conferees had come from as far away as Malaysia and Costa Rica to express their admiration for the leatherback and their fears for its future. They also wanted to "listen" to the animal, as one put it; others hoped to hear its "song" and seek its "counsel."

If a leatherback had prepared a résumé for the occasion, the document would gleam with superlatives: The turtle was a contemporary of the dinosaurs. Its direct forebears lived more than 100 million years ago. It typically weighs half a ton and reaches six feet in length. The record-holder leatherback weighed 1,997 pounds and bested nine feet.

Of the seven types of marine turtles, the leatherback is the widest roaming (a year’s journey of 7,000 miles has been measured) and the deepest diving (to 3,000 feet).

Like other sea turtles, it nests on tropical or subtropical beaches, but it is the only species to frequent the cold latitudes. It has been spotted as far north as the Aleutian Islands and as far south as Tasmania and Chile. "They go where they want to go," said conference participant Frank Paladino of IndianaPurdueUniversity.

Unique among sea turtles, the leatherback, as the name suggests, does not have a shell. Its body is protected by a thick sheath of cartilage, which is impregnated with oil and is waterproof. The animal’s back is brownish black with white speckles and is sharply ridged. Each turtle bears a pinkish spot on its forehead. Scientists aren’t sure what the spot does, if anything. One scientist referred to it as a "third eye," because a stalk from the animal’s brain extends to a point below the spot, where the skull is thinnest. Maybe the spot receives a signal of some sort. "There are a lot of secrets that this animal holds that we haven’t got to yet," said James Spotila, a biologist from DrexelUniversity in Philadelphia.

But the leatherback’s unfortunate distinction is to be one of the most endangered members of the imperiled sea turtle family. In the Pacific Ocean, where the majority of leatherbacks lived until recently, the population has crashed, from an estimated 90,000 nesting females in 1980 to a mere 3,000 to 5,000 today—the verge of extinction. Globally, the situation is only slightly less grim; in 20 years the number of females has declined from an estimated 115,000 to roughly 30,000.

Before its decline, some biologists had considered the leatherback extinction-proof, precisely because of its cosmopolitan reach. If colonies were wiped out in one part of the world, the thinking went, others would hold their own. But the great turtle is no match for industrial fishing fleets. In longline fishing, baited hooks are strung out behind ships for up to 50 miles. One authority at the conference said that perhaps as many as five million hooks, dangling from 100,000 miles of line, tear through the Pacific Ocean each day. Leatherbacks, attracted to the glowing lights attached to longlines, become entangled in suspended forests of hooks and drown unless they reach the surface to breathe.

On shore, creatures as varied as crabs, herons, raccoons and jaguars prey on leatherback hatchlings as they emerge from the sand and dash to the surf. People on six continents plunder leatherback nests for eggs, despite laws against such poaching, according to conference participants. Beachside condominiums and hotels also wipe out turtle nests. All told, fishing, poaching and development can be devastating. For example, a beach in Mexico called Mexiquillo that used to have 1,500 leatherbacks nest each winter had only 4 last year.

The goal of the conference, which was put on by the Caribbean, depleted leatherback populations are on the rebound, thanks to efforts to preserve beach habitats, and leatherbacks plying the Atlantic Ocean also appear to have fared better lately, because of closer regulation of the fisheries. As more than one speaker said: "Choose optimism."

Scientists seldom invoke a higher power in their work, but this meeting started with a Native American blessing. The group gathered outside amid blue-flowering ceanothus bushes. Anne-Marie Sayers, an elder of the Costanoan-Mutsen tribe, asked us to hold hands. One by one, attendees expressed hopes for the conference as they passed an abalone shell containing a clump of burning sage, whose smoke, Sayers explains, is traditionally used so "the eyes may see the truth, the ears may hear the truth, and the mouth may speak the truth."

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