Caribbean Sea Turtles Stage Comeback

The first week in May marked the emergence of the first hatchlings from leatherback turtles nesting on Sandy Point, St. Croix, U.S. Virgin Islands. If this year follows recent trends, it will continue one of the most positive turns for these endangered turtles, according to Earthwatch-supported findings recently published in the journal Biological Conservation.

The Biological Conservation paper reports on the results of monitoring and conservation efforts at Sandy Point National Wildlife Refuge, a three-mile stretch of beach on St. Croix, between 1982 and 2001.

The authors found a marked increase in the number of nesting leatherback females from less than 30 in the 1980s to 186 in 2001, as well as a more than 20-fold increase in annual hatchling production from around 2,000 to more than 49,000.

“There have been recent publications documenting long-term increasing trends for other species of sea turtles. However, our publication is the first to link nesting beach conservation to an increase for any species, and is the only long-term time series on leatherbacks,” said Dr. Peter Dutton, coauthor of the paper.

Dutton is a researcher with the U.S. National Marine Fisheries Service and principal investigator of Earthwatch’s Saving the Leatherback Turtle project, along with Jeanne Alexander-Garner (Texas A&M University) and Steve Garner (West Indies Marine Animal Research and Conservation Service).

Although leatherback turtles are at serious risk of global extinction, the rise of nesting populations on St. Croix holds promise for other nesting populations around the world.

The study also provides the first reliable estimate of survival probabilities for nesting adult female leatherbacks, through the use of Passive Integrated Transponder (PIT) tags and photo-identification. Using these dependable mark-recapture techniques, applied since 1992, the authors found a surprisingly high survivorship estimate of 89 percent.

“The reason we were able to do this was because of the consistent effort on the beach: patrols carried out every night, all night, every year for the entire nesting season,” said Dutton.

“This meant we were able to tag and monitor every female that nested, which would not have been possible without the consistent support from Earthwatch volunteers.”

Earthwatch’s Saving the Leatherback Turtle project began on St. Croix in 1982, under the leadership of the US Virgin Islands Department of Planning and Natural Resources. For the first four years, coauthor Rafe Boulon (now with the U.S. National Park Service) worked with field leaders Dr. Karen Eckert (Wider Caribbean Sea Turtle Conservation Network) and Dr. Scott Eckert (Duke University, and now principal investigator of the Earthwatch-supported Trinidad’s Leatherback Sea Turtles project).

In response to these earlier efforts, the U.S. Fish and Wildlife Service established the nesting beach at Sandy Point as a national wildlife refuge and became actively involved with the project in the 1990s.

Since the beginning, Earthwatch volunteers on Saving the Leatherback Turtle have worked with the changing cast of scientists, including Dutton and his wife and lead author Dr. Donna Dutton (Ocean Planet Research), to patrol Sandy Point each night of the nesting season.

They systematically identified each nesting turtle, counted its eggs, and moved nests that were at risk from erosion.

This year teams report that the first turtles nested on February 22, with hatchlings emerging the first week in May. They’ve had 71 turtles lay 150 nests so far, with 53 of those turtles returning from previous years.

Despite ongoing conservation efforts around the world, leatherback turtle populations have declined in recent years due to human impacts on nesting beaches and destructive fishing practices like longline fisheries.