GAINESVILLE, Fla. --- With loggerhead sea turtle nests in dramatic decline, researchers would love to know more about where the turtles go, and what they eat, so they can better protect the creatures' habitat.
Now, a team of University of Florida biologists from the Archie Carr Center for Sea Turtle Research teasing that information from the turtles' shells is reporting some surprising findings.
Doctoral student Hannah Vander Zanden writes in Tuesday's online edition of the journal Biology Letters that analyses of the chemical elements in the shells of 15 living female loggerheads suggests the turtles are remarkably individualistic in their range, diet, or both. The findings are unexpected because loggerheads -- named for their large heads -- are known to swim thousands of miles and eat 80 types of prey, often including crabs, whelks and many other ocean-bottom-dwelling creatures.
"The fact is, you have this big range of potential things they can eat, and potential places they can go, and it seems that individuals are not using that whole range," Vander Zanden said.
Although the findings need to be refined, the research could one day help scientists and public policy makers find and protect areas of the open ocean or coastal waters where loggerheads congregate or feed heavily. Such protection may be more and more urgent: On March 10, federal agencies proposed upgrading the turtle's status from "threatened" to "endangered" among seven Atlantic and Pacific populations.
Vander Zanden's findings also shed light on the turtles' habits over a span of 12 years, at least three times as long as the longest study involving satellite-tagged turtles -- proving the worth of analyzing shells, or similar tissues in other animals, that contain forms of elements known as stable isotopes.
"It really revolutionizes our way of looking at these animals that have this kind of tissue," said Karen Bjorndal, UF professor
|Contact: Hannah Vander Zanden|
University of Florida