Baby Sea Turtles Go Rogue, Satellite Shows

Image: Baby loggerhead turtle.
Satellite data shows that loggerhead sea turtles spend lots of time on the surface.Jim Abernethy

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/ Source: Live Science

Baby sea turtles may not all follow the path scientists suspected the animals would travel. In fact, new satellite tracking shows that at least some turtles drop out and head for browner — and warmer — pastures.

Scientists have long suspected that young sea turtles ride a large current called the North Atlantic Subtropical Gyre all the way around the ocean, popping back out on their original coastline after a year or two of growth. The first long-term satellite surveillance of young turtles, however, finds that many of the animals drop out of this current, perhaps following brown, floating seaweed called Sargassum that provides them with warmth, shelter and food.

We saw that a lot of the turtles had a similar movement pattern to what we expect Sargassum to do," said study researcher Kate Mansfield, a marine biologist at the University of Central Florida. [ Images: Tagging Baby Sea Turtles ]

Marine biologists track seagoing creatures, including adult loggerheads, with satellite tags that transmit information such as location, depth and temperature. But hatchlings are too small to tag — affix a tag with heavy batteries to these turtles, and they'll sink, Mansfield said.

Tagging turtles

Advances in tag technology have started to change all that. New tags are smaller and solar-powered (no heavy batteries needed), Mansfield said. They're still too large to affix to a newborn loggerhead, but they fit on young turtles. Mansfield and her colleagues lab-reared 17 loggerhead turtles to the age of 3.5 to 9 months, waiting until the turtles had reached between 4 inches and 7 inches (11 to 18 cm) in length before tagging them and releasing them into the Atlantic Ocean.

The long-standing expectation was that baby turtles hatch off the East Coast of the United States, launch into the Gulf Stream that carries them north up the coast and then ride into the North Atlantic Subtropical Gyre. This system of currents takes the turtles past the Azores off the coast of Western Europe and down the coast of Africa, before the animals pop back out on the East Coast again. [ The 10 Most Incredible Animal Journeys ]

—Stephanie Pappas, Live Science

This is a condensed version of a report from LiveScience. Read the full report.

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