New Riddles About Kemp’s Ridleys

Summer 1996 Issue Articles:

* Divine Intervention?
* New Riddles About Kemp’s Ridleys

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New Riddles About Kemp’s Ridleys

by David Godfrey

This year marks the 40th anniversary of the publication of The Windward Road, Archie Carr’s inspiring and award-winning book about his experiences studying sea turtles in the Caribbean. The book’s first chapter, “The Riddle of the Ridley,” explores the mysteries surrounding what was then the least understood of the sea turtles. Over the past four decades, many of these mysteries have been solved — often in dramatic fashion. It is unfortunate, however, that while the world was unlocking many of the mysteries surrounding Kemp’s ridley (Lepidochelys kempii), the species was rapidly slipping toward the brink of extinction. Today, a new set of questions has emerged among turtle researchers and conservationists about whether the severely endangered Kemp’s ridley may actually be showing early signs of recovery.

Solving the First Riddle

When The Windward Road was published in 1956, a considerable debate existed as to whether the Kemp’s ridley was indeed a separate species. Many at the time were convinced the Kemp’s (or Atlantic) ridley was nothing more than a hybrid the result of a loggerhead having mated with a green turtle. The debate persisted for many years, largely because no Kemp’s ridley was ever seen nesting. Even after Dr. Carr painstakingly searched throughout the Caribbean and the Gulf of Mexico, he could find no signs of nesting Kemp’s ridleys. If the turtle does not nest, many reasoned, then it must be a crossbreed. But Dr. Carr would not give up on his belief that the Kemp’s ridley was a separate species and that it regularly nested on some remote beach that simply had not yet been discovered. His goal was to find it.

The story of how Archie and the world finally came to learn of the Kemp’s ridley’s only major nesting site near Rancho Nuevo, Mexico, is gloriously recounted in Dr. Carr’s book, So Excellent a Fishe. The nuts and bolts of the story are that the nesting beach was miraculously revealed in 1965, when a forgotten black and white film shot by a Mexican architect 18 years earlier ended up in the hands of one of Dr. Carr’s colleagues in Texas. The film showed an arribada of at least 40,000 Kemp’s ridleys nesting in broad daylight on a tiny stretch of beach on Mexico’s Gulf coast. With the discovery of that priceless film, the world would not only learn where the Kemp’s ridley nested, there would now be documented evidence on the historic abundance of this creature.

A Species in Decline

By the time Dr. Carr saw the film in an Austin, Texas, classroom, the Kemp’s ridley was already in serious trouble. A combination of natural predation by coyotes and rampant poaching at the nesting beach had seriously dwindled the population. The greatest loss of ridleys, however, was coming at the hands of an unmonitored shrimping industry in the Gulf of Mexico, which was killing thousands of sea turtles each year by incidentally capturing and drowning them in trawl nets. According to a report prepared by Dr. Carr in the late 1970s, the number of nesting turtles at Rancho Nuevo had plummeted from approximately 40,000 in 1947 to just 1,200 in 1975. The population continued its drastic decline until 1985, when only 702 nests were deposited at Rancho Nuevo. This population collapse gave the Kemp’s ridley the dubious distinction of being the most severely endangered species of sea turtle in the world.

For almost two decades now an international coalition of scientists, conservation groups and governments has directed efforts at protecting the nesting beach and imposing regulations on the shrimping industry.

Each year, the nesting aggregation at Rancho Nuevo has been meticulously monitored and protected, but until recently, it looked as if none of the activities aimed at restoring the population were having much effect. Experimental attempts have also been made to raise hatchlings in captivity for a year and then release them into the wild a process called “head-starting.” But this effort, too, has seemed futile.

New Riddles

The number of Kemp’s ridley nests laid at Rancho Nuevo stopped declining in 1986 and has been steadily increasing ever since. Although the population is still far below historical figures, a status report on the species released in June 1996 by the Turtle Expert Working Group shows the number of Kemp’s ridleys appears to be growing exponentially. Last year (1995) saw the highest number of nests in two decades with 1,429 recorded at Rancho Nuevo. Is this recent trend simply a short-term fluctuation in nesting patterns or do these numbers mean the population is showing early signs of a recovery? This is the first of several important modern-day riddles about the Kemp’s ridley.

On the heels of the good news out of Rancho Nuevo, officials with the National Biological Service reported the first documented instances of headstarted Kemp’s ridleys returning to nest. The two turtles spotted in May nesting on Padre Island, Texas, were part of a highly controversial experiment conducted from 1978 to 1988 aimed at creating a new nesting colony on a beach that could be better protected than Rancho Nuevo.

The experiment involved taking Kemp’s ridley eggs deposited at Rancho Nuevo and moving them to a hatchery on Padre Island National Seashore. It was hoped the hatchlings would be “imprinted” with Padre Island as their natal beach and return there to nest after reaching adulthood. Over 13,000 hatchlings were allowed to emerge from the sand and crawl into the sea before being recaptured and taken to a laboratory to be raised through the normally dangerous first year of life. The yearlings were given flipper tags and identifiable marks on the backs of their shells before being released into the Gulf of Mexico. After about ten years, researchers began looking in earnest for signs that mature headstarted turtles were returning to nest at Padre Island. Of the thousands released, the two spotted in May are the first known to have survived to reproduce.

From the time headstarting began, many scientists and conservationists have criticized the program as a huge waste of money and effort that should be spent on proven conservation methods. Until this year, no one knew if even a single reproducing Kemp’s ridley was created out of the thousands of eggs taken from the wild population and after millions of federal dollars were spent. Clearly, the discovery of these two nesting turtles proves that headstarted turtles can survive to nest. But will maturing headstarted Kemp’s ridleys continue to nest at Padre Island, creating the possibility of a new nesting colony? And do these recent nestings mean the headstarting experiment should be embraced as a successful conservation tool? These are two controversial riddles that will be debated for years to come.

Until recently, no Kemp’s ridley was ever documented nesting on a Florida beach. That changed in 1989, when a Kemp’s ridley nest was documented on the Gulf coast of Florida 10 miles south of Clearwater. In 1994, a second ridley was spotted nesting at Clearwater Beach. This year, two Kemp’s ridleys nested in Florida one at Sanibel and another at Ponce Inlet, the latter being the first ridley known to nest on the east coast of Florida. In fact, the same turtle was spotted nesting twice just south of Daytona Beach in Volusia County. The irony associated with the Volusia County nestings is in itself a worthy story (see Divine intervention?).

Are the recent nestings in Florida, and others reported in North and South Carolina, evidence that Kemp’s ridleys are engaged in some random-nesting behavior that may one day lead to new colonies? Or have ridleys been nesting in sparse numbers on these beaches all along, overlooked until both the effort and training of nesting surveyors reached today’s levels? Once again, these are new riddles that, once solved, may tell us something about the survival outlook for Kemp’s ridleys.

Too Early to Celebrate

The Kemp’s ridley is still in serious trouble. In order for the species to have any chance at long-term survival, we must continue to identify and eliminate threats at sea. While nesting numbers for Kemp’s ridleys have increased, so has the number of dead turtles washing up along the Gulf Coast. Most experts directly link these strandings with activities of the shrimping industry, and regulations requiring the use of turtle excluder devices (TEDs) have not solved the problem. Unfortunately, many shrimpers already see the increased ridley nesting as an opportunity to declare success, and calls for weakening regulations are bound to get louder. If increases in the ridley population are to continue, efforts must be made to more wisely regulate commercial fishing and shrimping, and there must be better compliance with TED regulations.

Scientists working for and supported by Caribbean Conservation Corporation have been studying sea turtles for almost 40 years. One thing that nearly four decades of research has taught us is that you cannot accurately predict what is happening to a population of sea turtles by looking at trends over just a few years. With that said, however, recent events could finally give reason for cautious optimism that efforts to recover the Kemp’s ridley population are beginning to have an impact. If nothing else, the increase in nesting gives hope that the world’s most endangered species of sea turtle can be recovered if we keep doing the things we have been doing and continue eliminating threats.