With fewer natural predators, baby turtles have a better chance of reaching adulthood. Photo credit: ZA Photography/Creative Commons
The number of leatherback sea turtle nests at 68 different Florida beaches, a new study reveals, has increased dramatically since 1979. Since that time, Duke University researchers report, the number of nests has increased more than 10 percent each year.
This trend is good news for the endangered species, but researchers point out that the turtle's success may come at the expense of other ocean species.READ MORE: Epic Leatherback Turtle Migration Tracked by Satellite for First Time!
The report presents some "very encouraging news," says Larry Crowder, director of the Duke Center for Marine Conservation, "it suggests that conservation and recovery efforts mandated under the Endangered Species Act are paying off region-wide."
Certainly, he explained, the large increase is due to improved monitoring and protection efforts over the last 30 years. Unfortunately, other factors are thought to have contributed to the increase as well.
Most significantly, Crowder says, are changing ocean conditions due to climate change. These changes have led to an explosion in jellyfish populations which serve as the primary food source for leatherback turtles. With more jellyfish available, female turtles are able to build and rebuild fat reserves quickly, allowing them to nest more frequently.
In addition to subtle climatic shifts, overfishing and nitrogen pollution also favor jellyfish. Some researchers fear that a "jellyfish stable state"—one in which jellyfish rule the oceans—may be fast approaching.
As food sources have increased, populations of the turtle's primary predator—sharks—have completely collapsed in the Northwest Atlantic. With fewer predators, the turtle's have a better chance of surviving through adolescence and into adulthood.
And, even as nests in Florida have increased, they have decreased elsewhere. At Pacific coast beaches in Mexico and Costa Rica, nest numbers have plummeted and conservationists fear that extirpation in these areas is inevitable.
"The good news here," Crowder says, "is that while most sea turtles continue to decline, some sea turtles are increasing." Understanding how much conservation has played a role—and how significant changes in the world's oceans are—is key to expanding these regional success to other populations and other endangered species.
Read more about leatherback sea turtles:
Epic Leatherback Turtle Migration Tracked by Satellite for First Time!
Plastic Found in 1/3 of Leatherback Turtles, According to Study
Tens of Thousands of Leatherback Turtles Nest on Gabonese Coast
Puerto Rico's Plan to Turn Endangered Turtle Habitat Into a Golf Course