Swimming to Oblivion
To survive, the endangered ridley sea turtle will have to overcome pollution, shrimpers, and its own instincts.
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When one considers how prolific Kemp’s ridleys are, it’s a bit ironic that for years they were thought to be sterile. No one knew of a ridley nesting beach, and captured female ridleys never had eggs in them. Fisherman thought they were infertile hybrids of green and loggerhead turtles. One man told Archie Carr, “This yer [sic] ridley don’t have no young’uns. He’s at the end of the line, like a mule.” It wasn’t until 1961, when Corpus Christi biologist Henry Hildebrand brought to light a shaky, faded 1947 home movie of a Kemp’s ridley arribada of an estimated 40,000 clambering, jostling, milling animals, that scientists had the slightest proof that the turtle was in fact a spectacularly fecund species and that it nested in Mexico.
In the years since, information about the arribadas has remained elusive. Their trigger may be the water-borne secretions from eight or ten special glands, called Rathke’s glands, that empty through pores in the ridleys’ lower shells. Scientists don’t know for sure. Neither are they positive when the turtles mate, although they believe that it happens under water, days to weeks before the arribada forms. In the early sixties Brownsville shrimper Julius Collins encountered a flotilla of hundreds of ridleys off Ranch Nuevo. “Some of them were coupled,” he recalls, “male and female together, floating by. It was a wonder to see.”
On the beach, members of the reconnaissance team have quietly moved closer. Most of the time they wait till the turtle has finished and then rebury her eggs to hatch in a fenced area protected from predators. If they have the good luck to arrive before the turtle has laid, they can collect the cache for transfer to Padre Island. One person crouches behind the animal and begins to dig with her, lengthening the hole in between each stroke of her hind flippers. When the turtle positions herself to lay, he pulls on a pair of surgical gloves and stretches out on his stomach behind her. Under her shell he holds a sterile plastic bag (the kind used to carry organs for transplants). According to the theory of imprinting, certain animals—salmon for one—“memorize” the smell of their birthplace and use the memory like a radio signal to return to the site years later. For the turtle-imprinting experiment to work, the eggs to be hatched at Padre Island must not touch Ranch Nuevo sand; the odor of the beach might be transmitted to the embryo even through the shell of the egg.
While the turtle is methodically filling the hole and tamping the sand with her hind flippers, members of the team take the opportunity to measure her shell. They also use a large punch to attach a metal identification tag, like a cattle ear tag, to one of her front flippers, a procedure supposedly no more painful than having an ear pierced. As Tim Fontaine points out, however, “A turtle can’t fuss or scream, but you can feel its muscles quiver” when the punch pierces its flesh.
At beach headquarters the person who collected the eggs goes to the egg house and transfers his cargo to a special plastic-foam box (it looks a lot like a beer cooler) filled with moistened sand from Padre Island. Each clutch of eggs is piled up the way it would be in a natural nest. Unlike bird eggs, which must be rotated regularly to remain viable, turtle eggs cannot be jostled. The embryo attaches by a thin membrane to the top of the shell after the first 24 hours, and for two and a half weeks any movement or shock can dislodge and kill it. The eggs then may be carefully moved, and 45 to 55 days after they were laid they will hatch.
Turtle nesting time at Rancho Nuevo today is a model of order and care, but in the days of the huge arribadas, it was chaos. Even before the turtles had left, coyotes, village dogs, coatimundis, and skunks would descend upon the beach, dig up the nests, and gulp down as many eggs as they could find. Even when the eggs weren’t eaten they were ruined for hatching. But the loss of eggs to animals, heavy as it was, was minor compared with the damage done by human predation. Dearl Adams, 72, a Brownsville man who in the sixties personally saved thousands of ridley eggs by transporting them to South Padre, says, “Back then, when the arribadas would come in, everybody from the villages would have him a turtle, waiting for her to lay.”
If the only pressure on the ridleys had been the coyotes and the local people, the turtles probably could have lasted. But ultimately they received a devastating blow: the outside world got wind of the arribadas. Before then, the problem was just men on horseback riding out with saddlebags full of turtle eggs to sell. By the early sixties, buyers were coming in carryall trucks, lumbering down the mud-clogged road at nesting season to buy every egg they could get. At 1,000 pesos (about $80) a hundred, the eggs represented valuable seasonal income. And—for a time—there were millions of them.
Where did all the turtle eggs go? For the most part, they ended up in cantinas, where their imagined aphrodisiac qualities placed them in high demand. The accepted macho procedure for consuming one—they were always eaten raw—was to tear a small hole in the shell, apply liberal quantities of salt, pepper, and lime juice, suck out the contents, and chase it all with a beer. Adams recalls once seeing a three-foot-high pyramid of turtle eggs on a table in a bar. The eggs were also sold in markets, right alongside the chicken eggs, and those not used right away were pickled to be eaten later.
Considering the mythic quality of turtle eggs in Mexico, one has to wonder if they are worth eating. “Turtle eggs are terrible,” says Jack Woody. “They’re fishy when they’re raw, and the taste would gag a maggot.” Dearl Adams is of two minds. The eggs of one other species he tried were pretty bad, but ridley eggs, he says ruefully, “are some of the best there are.” One rather strange aspect of turtle eggs is that the white does not solidify when boiled, which means it is always runny. Although that feature is not particularly desirable in most cooking, it’s perfect for baking. Before the Endangered Species Act was passed in 1973, bakeries in Florida proudly advertised that their extra-moist cakes were made with turtle eggs.
Today in Mexico it is illegal to sell the eggs of any species of sea turtle, but that hasn’t stopped the black-market trade. In certain Mexico City markets you can buy a turtle egg, shelled, in a Dixie cup, for 1,000 pesos—50 cents.
When approximately two thousand turtle eggs have accumulated in the shed at Rancho Nuevo, Pat Burchfield, 45, curator of the Gladys Porter Zoo and field coordinator at Rancho Nuevo, prepares for the biggest headache of his job: getting the eggs to the United States all in one piece. As often as not on egg-export day, the dirt landing strip is under water from recent rains, so the plane has to land on the beach. Says Burchfield dryly, “We’ve had a couple of landings that weren’t exactly thrilling.” After seven years he has mastered the juggling act of getting all the permits in order and bringing in officials from the Mexican government to make the presentation of the eggs to the United States. “I don’t want to sound like the postman,” he says, “but rain or sleet or snow—we fly those eggs.” The worst year he can remember was 1983, when Mexican customs officials confiscated the plane—with the eggs in it—for three days, leaving it to bake on the runway in Matamoros while zoo employees ran frantically back and forth across the border, trying to keep the sand in the boxes moist. Finally the plane was allowed to proceed, and miraculously, the eggs were unharmed.
Burchfield’s nerves don’t unfrazzle until he as cleared American customs in Brownsville and delivered the eggs to their foster home, the Padre Island National Seashore headquarters. There turtle-egg nannies Jennifer Bjork, 39, chief of environmental services, and Donna Shaver, 28, natural resources specialists, place each box inside a second plastic-foam box. This protects them from insects and increases hatching success, which has averaged 76 percent overall. Equally important, the boxes modulate temperature fluctuations. The sex of a turtle embryo is, like that of all reptiles, determined by temperature. At about 84 degrees Fahrenheit, the sexes are equally mixed. Above that temperature, more hatchlings tend to be females. Below, more are males. The two sexes look exactly alike until turtle puberty, when the male’s tail suddenly grows very long and stout.
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