Sea Turtles' Lost Years Revealed in New Study

By: By Laura Dattaro

Published: March 6,2014

 

 

 

 

The story of tiny sea turtles bursting from their nests in the sand and heading toward the ocean is well told. But what happens after that has long been a mystery to scientists, who call a turtle’s early life “the lost years.”
With a new study, University of Central Florida biologist Kate Mansfield has started to fill in the gap. Attaching sensors to hatchlings, which are only 3 to 4 centimeters long, has proved notoriously difficult, but Mansfield and her collaborator, Florida Atlantic University professor Jeanette Wyneken, discovered a solution capitalizing on the fact that the shells are keratin, the same material as human fingernails: They asked a manicurist.

A sensor attached to a young loggerhead sea turtle. (Jim Abernethy, NMFS permit 1551)

Using an acrylic base coat designed for fingernails, the researchers attached sensors to 17 lab-reared loggerhead turtles and sent them into the wild in batches from Florida’s east coast. The researchers tracked the turtles’ positions until the sensors stopped communicating, which took anywhere from 27 to 220 days. Scientists previously presumed that the sea turtles traveled along a giant current known as the North Atlantic gyre, which sweeps up the Gulf Stream, across to the Azores off the coast of Portugal and down to Africa and Cape Verde in a giant circular motion. But the trackers showed that the turtles, which aren’t particularly social, followed more individual paths, with some heading east into the Sargasso Sea. The researchers also confirmed that during these years, the young turtles never move back toward shore.
“We saw a lot of variation in their movements,” Mansfield told weather.com. “It wasn’t everybody hanging out in the Gulf Stream and then hanging out in the currents that make up the gyre. We had a lot more variation than we expected.”
The sensors also collected temperature data, which revealed that the young turtles spent a lot of time near the ocean’s surface, often floating among beds of Sargassum, a kind of seagrass. Because the turtles are cold-blooded, Mansfield said, it makes sense that they would linger near the surface, taking in sunlight to help them grow.

A turtle swims with a sensor on its shell. (Jim Abernethy, NMFS permit 1551)

Loggerheads are a threatened species with dwindling numbers. They eventually circle back to coastal environments and begin to reproduce when they’re about 25 to 30 years old, leaving many years during which they could be killed before adding to their population. Better understanding their movements in their early lives will ultimately aid in better protection and conservation efforts, Mansfield said.“There’s been this huge data gap for so many years,” Mansfield said. “This is kind of a first step in understanding what they’re doing and where they’re going and how they interact with the environment.”
MORE: Hundreds of Turtles Arrive on Mexican Beach

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An Olive Ridley sea turtle swims at Ixtapilla beach, in Aquila municipality on the Pacific coast of Michoacan State, Mexico, on October 13, 2013. More than 1,000 turtles are expected to arrive in the area daily this season. (HECTOR GUERRERO/AFP/Getty Images)

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