A single sea turtle mother may lay eggs on multiple beaches from Florida to Alabama in a single breeding season. The mobility of the mothers put them at risk from shrimp boats and fossil fuel drilling operations.
Biologists once believed that the loggerhead sea turtle (Caretta caretta) only laid eggs on one beach each year, but a U.S. Geological Survey (USGS) turtle-tracking project observed that turtle moms may travel several hundred miles during the nesting season and lay eggs on distant beaches.
“The satellite data and our observations on the ground tell the same story: loggerheads in this subpopulation nest at multiple beaches, sometimes hundreds of miles apart,” said lead author Kristen Hart, a USGS research ecologist in a press release. “Some of the females we captured and tagged on beaches in Alabama traveled over 250 miles to nest in Florida, where we recaptured them. Likewise, we also captured some females in Alabama that had previously been tagged at the Florida site in earlier breeding years.”
Loggerhead sea turtles are listed as endangered by the International Union for the Conservation of Nature.
The waters the turtle moms swim through hold many dangers, such as flipper-trapping fishing nets, speeding boats and toxic oil spills. As females move from one site to the other, it increases the chances of a tragic interaction with humans.
“These data show it is not sufficient to just protect habitat around high-density nesting beaches, such as the St. Joseph Peninsula, because many turtles that nest on the Peninsula use the entire region from the eastern Florida Panhandle to Louisiana,” said co-author and USGS biologist Meg Lamont in a press release.
Earlier this year, the U.S. Fish and Wildlife service proposed the protection of 739 square miles of loggerhead nesting beaches, according to the Office of the Federal Register. The proposed protected beaches stretch across six states and includes 36 distinct sites.
In at least one area, loggerheads nesting season 2013 has been a success, reported the French Tribune. Along a 35-mile stretch of Florida beach, 1,365 turtle nests have been counted so far this year by the Mote Marine Laboratories Sea Turtle Patrol. Although nesting numbers decreased from last years record of 2,462, nest sites have still increased compared to 2010.
However, that doesn’t necessarily mean 1,365 individual turtle mothers visited the Florida beaches. The news USGS study suggests population estimates based on nest counts may not be completely accurate, since some of those nests might have been made by the same mother.
IMAGE: A loggerhead sea turtle (ukanda, Wikimedia Commons)