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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.
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