Decline in Endangered Texas Turtles Linked to BP Spill

The decline of Kemp's ridleys, Texas' official sea turtle, can be attributed to over-harvesting of their eggs and incidental capture in fishing gear, but now experts say that that the 2010 BP oil spill may also play a role, setting back this species' recovery.

Kemp's ridley turtles are the most critically endangered sea turtles in the world, with a global female nesting population estimated at just 1,000 individuals, according to National Geographic. So with their survival hanging in the balance, after already bouncing back from near extinction, this latest news worries conservationists.

BP's Deepwater Horizon oil spill dumped about 4.1 million barrels of oil into the Gulf of Mexico, perfectly timed with the beginning of turtle nesting season. At the time, scientists found scores of dead baby Kemp's ridleys near Louisiana slick with oil. And after researchers behind a new study stumbled upon 29 sea turtles returning to the spill area between 2011 and 2012, with oil still in their shells, they now suspect that the disaster has something to do with their decline.

"It was on a rapid road to recovery and the recovery came to an abrupt halt in 2010, and we don't know why," researcher Selina Heppell, a professor at Oregon State University, told the Houston Chronicle. "What the modeling suggests is that something very dramatic and unprecedented happened to the survival and reproduction of the species."

Blame it On the Oil?

Heppell created a model used to calculate the turtles' nesting population to help determine whether or not the downward trend in nesting seen since 2010 was related to the BP spill. Experts do note, however, that the only way to say for sure that the oil seen in this group of turtles came from the spill would have been to test their blood right after it happened.

Of course, BP contends that lots of other factors could be undermining Kemp's ridley recovery. Jason Ryan, a spokesman for the oil conglomerate, noted several factors, "including natural variability, unusually cold temperatures and accidental capture in fishing gear."

"Over the last two decades, there have been several significant drops in Kemp's ridley nestings in Texas," he added, "including in 2003, when a record year in 2002 was followed by a 50 percent decline the next year."

Efforts to save this species began in 1970 when Kemp's ridleys, the smallest among sea turtles at just two feet long and 100 pounds, were added to the Endangered Species List. And with only a handful of hatchlings surviving the dangerous trek from the sand to the ocean each year, boosting population numbers is difficult, notes National Geographic. (Scroll to read on...)

The number of nests dropped from an estimated 40,000 in 1947 to about 1,000 by the 1980s.

Key to the recovery of the Kemp's ridley was the creation in 1978 of the joint US/Mexico project, Rene Marquez, who headed the project, told the Chronicle. About 100 juveniles from Galveston were dropped off at the Cayman islands in 1980 - a population that quickly flourished and once returned to Mexico in 1988, showed promise for recovery.

But with miles of the Gulf seafloor still slick with oil from the spill, impacting wildlife such as dolphins and coral reefs, researchers are suspicious of its effects on Kemp's ridley sea turtles as well.

Expert Kimberly Reich of Texas A&M University in Galveston, who conducted the latest study, pointed out evidence in the fact that the nesting patterns of these turtles coincide with the 2010 spill. Kemp's ridley turtles nest about every two years, meaning that those animals exposed to oil in 2011 and 2012 would have nested in 2013 and 2014, years that saw drastic drops in nesting numbers.

Reich's three-year study, along with a host of others that are underway, can hopefully shed light on the situation of Kemp's ridleys and help scientists better determine how to protect this ancient species.

"We hope that when we come together, all our research will paint a picture," Reich concluded.

The study's results have yet to be published and were presented at the Second International Kemp's Ridley Sea Turtle Symposium in Texas.