Swimming to Oblivion
To survive, the endangered ridley sea turtle will have to overcome pollution, shrimpers, and its own instincts.
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The vigil begins. In a natural nest, hatching takes about four days, as first one and then another turtle tears and struggles its way out of the shell. That sends a drizzle of sand around the remaining eggs, raising the bottom of the nest like an elevator, until the entire squirming mass of baby turtles is carried up and into the open air. Of course, a box in the turtle shed at Padre Island doesn’t bear much resemblance to a natural nest, so the turtles get some help.
As each one begins to emerge from its egg, it is solicitously dug out of the sand and brushed off. Freshly hatched, a ridley turtle is about the size of a silver dollar. Its upper shell is black, with multiple peaks, or keels, that will smooth out as the animal matures. At this point, it looks like most baby turtles, but when it is a few months old, the underside and the edge of the upper shell will begin to turn creamy white, and eventually the upper shell will change to a uniform gray. At about a year, the ridley’s flat, broad shell looks like a fat pancake.
Turtles almost always hatch at night, and within 24 hours they are usually ready for their baptismal swim. Around six in the morning someone drives the tiny animals to the beach and puts them on the sand. As the sun rises in the sky the turtles turn instinctively toward the light over the ocean. Then, says Bjork, “they run off toward the water like windup toys.” Plowing along with their noses and chins, the hatchlings look as if they could be sniffing the sand or perhaps checking the grain size, much as their mothers do when they land at Rancho Nuevo. The turtles are allowed to paddle in the surf and dive a couple of times. Then, their taste of freedom over, they are netted like guppies, counted, measured, and weighed. Finally they are placed on moist foam pads for the five-hour drive to the place where they will spend the next year of their so-far very unnatural lives, the National Marine Fisheries Laboratory in Galveston.
The ridley’s new home at the Sea Turtle Head Start Project consists of three 96-foot-long Quonset huts covered with heavy plastic sheeting. Each animal has private quarters in a plastic-gridwork container placed in one of numerous long fiberglass tanks of water pumped in from the nearby Gulf. The moisture-laden air and tropical temperature are heaven for turtles but hard on humans, and in the summer, says Head Start supervisor Tim Fontaine, “it smells to high heaven.” Keeping the turtle nursery going costs $400,000 to $500,000 a year, funded partly through the federal Endangered Species Act. The return of tags from Kemp’s ridleys that have been caught indicate that a year in a tank doesn’t seem to give them any difficulty in adapting to the rigors of life in the ocean. Over ten years, more than 12,000 turtles have been raised here.
The routine is much like that of a zoo—feed the animals, clean the cages—but getting it down wasn’t easy. “The first year, no one knew anything about raising ridley hatchlings” says Charles Caillouet, Jr., 50, the chief of the lab’s life studies division. So workers put all of the tiny turtles together. The three-ounce ridleys lit into each other with murderous intent. Says Fontaine, “We had animals with their flippers chewed off and their eyes eaten out—the ridley is a vicious, mean, antagonistic, pit bull of a sea turtle.” The horrified workers had to resort to isolating the injured turtles in buckets (not red buckets—that really riles them), but injuries coupled with infections eventually did in a third of the original group. The overall survival rate today is 89 percent, and in 1987 it was 99 percent.
Head Start turtles grow faster than their wild brothers—but they pay a price. In the ocean, ridleys dine on a bouillabaisse of crabs, clams, mussels, snails, jellyfish, barnacles, and the occasional fish. At the Galveston laboratory, they get pellets of sensible, high-protein Purina Sea Turtle Chow. At three months, they’re old enough to start tagging. The first kind of tag they receive is a “living” tag, which consists of a quarter-inch plug of the animal’s white bottom shell grafted to its black upper shell. Later a sliver of magnetized wire is injected into one front flipper. When the turtle has put on a couple of pounds and has grown to Frisbee size, it receives a punch flipper tag. The final type is the experimental “pit” tag, an injected silicon chip. All but the punch flipper tag, which eventually corrodes away, will probably last longer than the turtle does.
Ridley release day usually comes in May or June. “It’s a grand event,” says Fontaine. “Every year I expect interest to diminish, but people keep showing up.” The turtles are packed in large corrugated-cardboard poultry boxes and loaded in rented trucks for the trip to Padre Island. As press cameras and Instamatics click, a University of Texas research vessel filled with boxes of turtles heads out to sea. About twelve miles out, the ridleys’ keepers see the last of them as the animals are dropped, rather unceremoniously, into the murky water of the Gulf. For a few seconds the turtles twist and spin in the frothy wake. Then, regaining their equilibrium, they exit swimming, with quick, strong strokes.
For every thousand turtles that hatch in the wild, maybe one or two survive to adulthood. The first few years of life are perilous, and like any vulnerable young animal, a baby ridley turtle hides. It becomes a turtle-in-residence among the abundant sworls of sargasso and the drift lines of plants and debris that form on the surface of major currents in the Gulf. There it grows until a diet of small marine life no longer suffices, at which point it abandons its safe harbor to dive for crabs in waters closer to shore. No one is sure what happens then. It may stay in the Gulf, or it may travel with the ocean currents up the Atlantic seaboard, but one day—ten or even twenty years later—its hormones awaken. Breeding time has come.
The theory of imprinting may explain how a mature turtle finds its birthplace—now its nesting beach—once within sniffing range. It hardly explains what intelligence guides the creature across the Gulf of Mexico. Maybe, like certain birds, turtles navigate by the sun or stars. Perhaps they pop to the surface en route to scrutinize landmarks or analyze the subtle sound pattern of waves on different shores. Or they could simply fall in with the pack and learn the way from the old turtles. One of the most provocative theories holds that they read the rocks. If the ridley has magnetite in its brain—as do the loggerhead and green turtles—who’s to say that it might not memorize the magnetic fields surrounding underwater rocks and strata? With a handy internal geomagnetic map, it could then find its way to Rancho Nuevo or to Padre Island National Seashore, whichever place felt like home.
Ten years of intensive care of the Kemp’s ridley are concluding with the patient still on life support and no end in sight. So far, no Head Start turtles have been discovered nesting anywhere. Possibly they need more time to mature than the eight to ten years that were previously thought. Maybe the imprinting program, rather than establishing a new migratory pattern, has scrambled the data, so that Head Start turtles will end up nesting who knows where. For the present, protection of the beach will continue, but the egg-imprinting experiment is scheduled to end after 1988. As Jack Woody says, though, “if six or seven turtles stagger up on Padre Island some day, we could always go back and reevaluate.”
People close to the program look at it and see different things. Tim Fontaine wonders if the arribada is not actually extinct already, a geriatric remnant slowly dying year by year. “Until I see the handwriting on the wall, I’ll never give up,” he says, “but if we don’t have an upward trend soon or have some Head Start turtles come back, they’re doomed in five to ten years.” Peter Pritchard, a ridley authority and the vice president of the Florida Audubon Society, takes a more hopeful view. He says, “Perhaps an arribada is not a permanent phenomenon.” The turtles are quite capable of nesting singly, some new females are showing up in Mexico each year, and young ridleys are found in the South Atlantic. Perhaps the Rancho Nuevo arribada was never meant to be forever.
How sad, though, to think that a faded home movie, rainy with scratches, might be the last anyone will ever see of the splendid arribadas of the Kemp’s ridley. One hopes they can be restored—in part to preserve the balance of nature, in part to ensure that another species does not perish at the hand of man. But perhaps the most honest reason to preserve them is for our own delight, because the strange and beguiling ways of this earth’s creatures are a wonder to see.
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