A new US Geological Survey study suggests that the threatened loggerhead sea turtle may require broader habitat protection during the nesting season.
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“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.
Satellite data and researchers observations confirm that the loggerheads nest at multiple beaches and sometimes these beaches are hundreds of miles apart.
Co-author and USGS biologist Meg Lamont stated: “On average, the tagged turtles visited areas about 33 kilometers (20 miles) from shore and moved about 28 kilometers (17 miles) to nest at another beach.” However, researchers also identified several turtles nesting both in Alabama and on the St. Joseph’s Peninsula in Florida, which is nearly 250 miles away, and these individuals were identified at both locations in a period of just two weeks!
The results of the study solved the mystery of why fewer nesting loggerheads were returning to their same nesting spot on the Peninsula. “We didn’t know whether they were dying or simply nesting elsewhere,” explained Lamont, “Now we know they aren’t as faithful to one nesting site as was once thought.”
“These data show it is not sufficient to just protect habitat around high density nesting beaches … because many turtles that nest on the Peninsula use the entire region from the eastern Florida Panhandle to Louisiana,” said Lamont.
“We are working towards defining areas where sea turtles concentrate their activities at sea, effectively building a map of in-water turtle hotspots,” said Hart. “The more we know about their habitat use, the more questions are raised about their behavior and ability to adapt.”
For more information visit the USGS Newsroom.
Loggerhead turtle image via Shutterstock.