While scientists in several states are studying the effects of the oil spill on loggerhead and other sea turtles, the Kemps ridley have been of particular concern. The Deepwater Horizon explosion on April 20, 2010 happened when they typically would have been in the area. Most of the 456 visibly oiled turtles rescued by the U.S. Fish and Wildlife Service last year were Kemps ridleys.

At the peak of nesting season, their numbers looked good. As of May 24, 155 Kemps ridley nests had been spotted on Texas shores — more than in all of last year and more than had been counted by that day in 2009 and 2008. The same is true for some other sea turtle species, although they have just started to nest so it might be too early to have confidence in those numbers.

And because sea turtles don't reach reproductive age for at least a decade, the full effects of the oil spill might not be known for years.

"There is fear that some of the turtles that took the year off from nesting or after the turtles were done nesting during the 2010 year, that they entered the waters where the oil had been present," said Shaver, explaining that the reptiles often forage off the hard-hit Louisiana, Alabama and Mississippi coasts before or after nesting along the Texas Gulf Coast.

"There is concern that perhaps those turtles have been impacted from the oil and could then have problems with their reproduction," she added.