Unlocking the secrets of sea turtle migration

"We're starting to realize that developmental migrations -- ones that sea turtles make before they mature -- are even more amazing," says Dr. Peter Meylan, professor of natural sciences at Eckerd College in St. Petersburg, Florida. "They only do it one time, but it can be much longer than the reproductive migrations they do as adults and may involve tens of thousands of kilometers."

Meylan has been tagging and tracking sea turtles with his wife, Anne Meylan of the Florida Fish & Wildlife Research Institute, and Jennifer Gray and other colleagues from the Bermuda Aquarium. They have compiled the results of long-term capture programs in Caribbean Panama (17 years) and Bermuda (37 years) in a summary paper, "The Ecology and Migrations of Sea Turtles: Tests of the Developmental Habitat Hypothesis," in the Bulletin of the American Museum of Natural History.

"Bermuda is a place where young turtles go to grow up," Meylan says. "They arrive there after living out in the ocean. In Bermuda waters they grow from about the size of a dinner plate to the size of a wash tub, and then move on to different, adult habitats."

For example, some green turtles hatched in Costa Rica were spending their "growing up" years thousands of kilometers away in Barbados, North Carolina and Bermuda before heading off to spend their adulthoods near Nicaragua.

Young turtles have already survived hatching from their untended eggs, escaped hungry predators on their rush to the ocean, and have avoided marine predators once there. This research points to developmental migrations as another vulnerable time for sea turtles.

"Tag-return data from this study suggest that this may be another dangerous time for these turtles, and protection as they move into their adult foraging ranges could be a productive objective of policy change for effective marine turtle conservation," says Meylan.