WE HAVE all seen images of turtle hatchlings scrabbling down a beach to the sea. But between then and their appearance at foraging grounds as adults, no one knew where they went. Now a study of ocean currents and turtle genetics suggests an answer: they go pretty much everywhere.
Tagging doesn’t work on green turtles (Chelonia mydas) – they are just too small, says Nathan Putman of Oregon State University in Corvallis. “Any tags you put on them would sink them.” To figure out where they go, Putman teamed up with geneticist Eugenia Naro-Maciel of the City University of New York. They used a model of ocean circulation to estimate where the young turtles would be carried from natal beaches in the Atlantic, Mediterranean and Indian oceans. They also compared the genetic make-up of baby turtles at those beaches with adult turtles at foraging grounds. By combining the two methods, they were able to produce maps showing where turtles go after hatching (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2013.1468).
Putman and Naro-Maciel think the turtles are found in two main areas. One covers most of the north Atlantic, plus the Caribbean and Gulf of Mexico. The other spans much of the south Atlantic and extends into the Indian Ocean south of Madagascar – a daunting challenge for conservationists hoping to preserve them, says Putman.
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