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Night of The Sea Turtle

Researchers in Puerto Rico study the determined nesting of the giant leatherback, a species that migrates to Long Island each summer

By Joe Haberstroh | Staff Correspondent

May 11, 2003

Along the northern shore of this tiny island, Playa Brava was bathed in prehistoric darkness. No artificial light shone near the protected beach. The almost palpable blackness was relieved only by the stars, the Milky Way appearing like a galactic hammock woven with the brightest of diamonds.

On shore, a group of turtle biologists and volunteers settled in for the night. Their leader: Sam Sadove, a Long Island scientist who at dusk had led the party to the beach by way of a jungle trail lined by thick stands of beach grape and mangrove. To the south, clouds massed and a breeze freshened the warm, salty air. Sadove and others spoke in whispers, stayed low on the beach and signaled with flashlights fitted with red filters. They treaded lightly to keep from frightening the extraordinary and reticent animal they hoped to study when it came ashore to nest - the leatherback sea turtle.

The leatherback favors rough ocean beaches such as Playa Brava - Ferocious Beach - to lay eggs before returning to the ocean and swimming north to places such as Long Island Sound, Gardiners Bay and the waters off Montauk. It spends the summer and fall eating jellyfish and other gelatinous creatures. Invisible in the depths, the leatherback is nevertheless as native to Long Island as seasonal songbirds and migrating bluefish.

With some males weighing 2,000 pounds and measuring 8 feet long, leatherbacks are by far the largest turtle in the world. Front flippers extended, some leatherbacks have a wingspan of 15 feet. Starting with its soft, leathery carapace - it does not have a hard shell - the species' physiology is unique among reptiles. Heat exchangers at the shoulder prevent cold water at the flippers from cooling the whole body, which allows the turtle to maintain a fairly constant body temperature whether it is swimming near Greenland or Brazil. On its singularly deep dives - 3,000 feet is routine - it does not rely only on its lungs to stay underwater for an hour. Instead, it stores oxygen for long periods in its blood, not simply in its lungs, which compress under deep-water pressure.

"It's an athlete - that's the only way to put it," said biologist Molly Lutcavage, a senior researcher at the New England Aquarium in Boston, who is studying the Puerto Rican leatherbacks with Sadove. "It does everything to a greater extent than all its fellow sea turtles, and all its fellow reptiles."

Impressive, the turtle also is imperiled. It is listed as endangered by the state of New York and by the federal government. Human settlement has robbed the turtle of many of the nesting beaches it has used for millions of years. Even today, vacation resorts have been approved for two nesting beaches on the main island of Puerto Rico, 17 miles west of Culebra, and scientists fear the developments will drive off the turtles. Historically, island populations from Puerto Rico to Malaysia also have eaten the turtles, and poachers continue to steal leatherback eggs, which are still sold pickled in Caribbean taverns as an aphrodiasic. That practice might be dismissed as a barroom gimmick, but it has its genesis in ancient reverence for turtles.

"In many different cultures, turtles have the same significance - to many people, they mean prosperity, long life and fertility," said Hector Horta, who manages turtle-nesting areas for Puerto Rico's natural resources agency.

Fishermen around the world inadvertently also drown the giants in their nets and on their hooks. Leatherbacks are routinely ensnared in Long Island Sound and in the waters off Montauk in the long ropes that link lobster traps and their surface buoys. No one knows how many leatherbacks are out there, but estimates of the nesting female population in the Atlantic Ocean range from 5,000 to 7,000, down from more than 100,000 in the early 1980s.

If people hope to help the leatherbacks, they need to know more about their mysterious habits. In recent years, a determined group of turtle scientists has begun to deploy battery-powered tags linked to satellites. They have discovered that after nesting in Culebra, the turtles swim to Long Island, but also to Europe and Africa. They are the most widely distributed reptile on Earth.

"The turtles we tag here can be caught in a whelk pot in Wales," Lutcavage said.

People have long described leatherbacks as ocean wanderers. In fact, Lutcavage and Sadove say the tag information suggests that the turtles may move in well-traveled corridors across the seas. If verified over several migratory seasons, such corridors could help fishermen avoid the animals at different times of year.

'Tortuga!" comes the excited whisper from a Spanish-speaking team member crouched closer to the Brava shoreline.

"Turtle!" says another team member.

"What?" asks Sadove.

"A turtle! We have one."

"Oh geez, already? OK, OK, here we go," Sadove says. "Donde?"

A voice in the darkness: "Right here. Right here."

Sadove and Lutcavage have been arranging the equipment needed to attach a satellite tag to the spongy back of one of the turtles. They peer toward the water's edge, where a hulking shape gathers form.

It looks like a boulder.

But it moves.