The old adage βyou are what you eatβ is helping scientists better understand the threatened loggerhead turtle, which is the primary nester on Central Floridaβs beaches.
A study published today in the journal PLOS ONE describes how scientists at the ΒιΆΉΣ³»΄«Γ½ used a technique that links chemical signatures of the turtlesβ diets and their watery environments to their migratory routes. They found the technique just as effective as expensive satellite tracking.
Little is known about the turtles, which spend 99 percent of their time in the water and return to the Archie Carr National Wildlife Refugeβs beach to nest once every two to three years. The 13-mile-long beach is home to the second-largest population of loggerheads in the world and to about one of every four nests those turtles lay in the United States.
While other turtlesβ nests are increasing along the refugeβs shores, the loggerheadsβ have been declining since 2000. The technique validated by the ΒιΆΉΣ³»΄«Γ½ scientists could help managers preserve the turtlesβ nesting grounds, migration routes and foraging grounds, all of which are critical to their survival.
βWe need good information so policy makers can focus the limited conservation funds available where they can make the greatest impact,β said Simona Ceriani, the ΒιΆΉΣ³»΄«Γ½ graduate student who led the study. βWe all want our children to see these beautiful creatures and not just read about them in a book.β
In addition to validating the tracking technique, the study found that the foraging area for the Florida turtles is much broader than previously thought.
βThink of these turtles as Florida tourists and snowbirds,β Ceriani said. βThey come and nest and then go back to lots of different places. And while we knew some went back north, we had no idea that this was a popular destination.β
Based on her tracking, some turtles head for the water off the shores of Virginia and Delaware while others go to the Bahamas and the Gulf of Mexico. Some stay off the coast of Central Floridaβs beaches. Previously, scientists believed the majority of the loggerheads headed south.
While there are efforts to protect the turtle nests on the beaches, protecting their foraging grounds is equally important, biologists say. Many turtles die because they accidently get caught in fishing nets or encounter other dangers while out at sea.
The technique Ceriani validated should aid those efforts.
She took small blood samples from turtles at the refuge and completed a chemical analysis, which measured distinct markers known as stable isotopes. She also attached transmitters to the turtles so she could follow them using the more expensive but proven satellite tracking technique. The isotope approach proved to be equally useful, and it is much less expensive.
βBy combining isotope research with satellite tracking technology, we are learning exciting information about loggerhead sea turtles,β said Daniel R. Evans, a research specialist at the Sea Turtle Conservancy and co-author of the research paper. βThis research helps scientists and conservation managers identify key feeding areas for loggerhead turtles and helps direct policy and regulations that protect sea turtles in these specific areas.β
Ceriani said she will continue to research the migratory routes by adding more loggerheads to the study.
Ceriani earned her bachelorβs degree at the University of Milan in Italy and was a research fellow at Florida Atlantic University before joining ΒιΆΉΣ³»΄«Γ½βs PhD program in conservation biology in 2007.
Others who contributed to the study include:Β ΒιΆΉΣ³»΄«Γ½ Biologist, John Weishampel, James D. Roth from the University of Manitoba in Canada and Llewellyn M. Ehrhart from the Marine Turtle Research Group at ΒιΆΉΣ³»΄«Γ½.
Several grants from Floridaβs Sea Turtle Grants Program funded this study. The program gets is funding from the sale of the .
Sea turtle monitoring at the Archie Carr National Wildlife Refuge was coordinated through the ΒιΆΉΣ³»΄«Γ½ Marine Turtle Research Group, with funding from Brevard County, the Florida Fish and Wildlife Conservation Commission, the United States Fish and Wildlife Service and the United States National Marine Fisheries Service.