From: http://www.ouramazingplanet.com/3515-tracking-loggerhead-sea-turtles.html
Blood Tests Show Where Loggerhead Turtles Go
OurAmazingPlanet Staff -
Sep 21, 2012
11:34 AM ET
Every year, thousands of endangered loggerhead sea turtles crawl
ashore at Florida's Archie Carr National Wildlife Refuge to lay
eggs before dragging their leathery bodies back into the sea. But
where they go after their trek isn't well-known.
Scientists can
use GPS devices to record turtles' travels, but these
geolocator tags are expensive, and may be lost if turtles die. A
group of researchers has come up with a less expensive, easier
way to
find out where loggerheads voyage : testing their blood. A new
study, published Sept. 20 in the journal PLoS ONE, found that
this technique is just as accurate as using GPS tags.
The technique examines carbon isotopes in the turtles' blood,
which come from the food the animals eat. Carbon has different
isotopes, or variants, present in all living things, and the
exact mix of isotopes varies by region; for example, the mixture
in the mid-Atlantic is different from that of the Caribbean. By
examining the mixture of carbon isotopes in the turtles' blood,
scientists could determine the region to which the turtles
migrated.
The study found that 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 also stay nearby, off Florida's
coasts. Previously, scientists thought that the majority of the
loggerheads headed south, according to a release from the
University of Central Florida.
"Think of these turtles as Florida tourists and snowbirds,"
Simona Ceriani, a University of Central Florida graduate student
and study co-author, said in a statement. "They 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."
While there are efforts to protect the turtle nests on the
beaches, protecting the foraging grounds of this
endangered species is also important, the release noted.
Many turtles die because they get tangled in fishing nets
or encounter other dangers while out at sea.
"This 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," said Daniel R. Evans, a researcher at the Sea
Turtle Conservancy and study co-author, in a statement.
The Archie Carr National Wildlife Refuge 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 populations of other turtles have increased in the
refuge, loggerhead numbers there have declined for unknown
reasons.
