DAVIE, Fla.-- Threatened loggerhead sea turtles in the northern Gulf of Mexico can travel distances up to several hundred miles and visit offshore habitats between nesting events in a single season, taking them through waters impacted by oil and fishing industries.
Evidence from a U.S. Geological Survey study challenges the widely-held view that sea turtles remain near one beach throughout the nesting season and suggests the threatened species may require broader habitat protection to recover. The findings also cast new uncertainties on current estimates of the size of the species' Gulf of Mexico subpopulation.
"This is the first study to locate and quantify in-water habitat use by female loggerheads in the Northern Gulf of Mexico subpopulation during their reproductive periods," said lead author Kristen Hart, a USGS research ecologist. "Our tracking results show they depend on a much broader range of habitat during this critical part of their lives than was previously thought to be required."
The study reveals detailed loggerhead movements during "inter-nesting" periods, showing patterns that vary for individual turtles. Generally, this period begins when a female returns from open seas around May and lasts roughly until September. Up until now, efforts to protect the species generally centered on beaches with high nesting activity under the assumption that once turtles had nested on those beaches, they either remained in their immediate vicinity or migrated back out to sea.
"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 Hart. "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."'/>"/>
|Contact: Hannah Hamilton|
United States Geological Survey