6 March 2026 | 13:00 - 14:00
Philippe Gaspar (Mercator Ocean, France) will give this seminar, organized by the ELI-E department.
As soon as they leave the nest, the little turtles enter the sea. We then lose sight of them for several years until the day when, as adults, they return to lay their eggs on the beach where they were born.
It was long believed that during these lost years, juvenile turtles drifted with the ocean currents. To test this hypothesis, we analyzed the trajectories of more than 200 loggerhead turtles tracked by satellite in the North Pacific and compared them to the trajectories of surface buoys deployed as part of the Global Drifter Program.
Our results reveal that these turtles behave very differently from drifting buoys. They undertake extensive seasonal migrations and then, as they approach sexual maturity, swim against the current back to their birthplace.
Our analyses suggest that they use their perception of daylight hours and the Earth's magnetic field to navigate. These results should ultimately enable us to model, and therefore predict, the distribution of juvenile turtles at sea in order to better protect them.