It has been proposed that animals migrating towards a specific destination may rely on vector navigation by maintaining a direction for a certain amount of time. In sea turtles, reliance on this strategy has been proposed especially for migrations directed towards wide targets and carried out in weak sea current flows. In the present study we tested if vector navigation could also be a feasible strategy for turtles facing dynamic oceanographic conditions by considering the case of green turtles nesting in the Comoros archipelago and migrating to their foraging grounds along the African coast. To test this hypothesis, we firstly analysed the turtles’ actual headings estimated considering the currents encountered by migrating turtles along the open sea segment of their routes. We then run individual-based models to simulate the journeys of turtles migrating in the area while relying on a vector or a true navigation strategy, and reconstructed the turtle’s water-related, i.e. motor paths, by removing the drifting effect of sea currents. Tracked turtles did not show any major change in their headings and mostly oriented towards the foraging area. While simulations did not provide homogeneous results, the turtle orientation efficiency estimated from motor paths showed that they possibly relied on a vector rather than a true navigation strategy. The present results suggest that vector navigation is a viable strategy to account for the migratory performances recorded in turtles migrating in dynamic oceanographic conditions, even if the involvement of the more sophisticated true navigation mechanism cannot be completely excluded.

有人提出，向特定目的地迁移的动物可以通过在一定时间内保持方向来依赖矢量导航。在海龟中，已经建议依赖这种策略，特别是针对广泛目标并在弱海流中进行的迁移。在本研究中，我们通过考虑在科摩罗群岛筑巢并迁移到非洲海岸觅食地的绿海龟的案例，测试了矢量导航是否也可以成为面临动态海洋条件的海龟的可行策略。为了验证这一假设，我们首先分析了海龟的实际航向，考虑了迁徙海龟沿其航线公海段遇到的水流。然后，我们运行基于个体的模型来模拟海龟在该地区迁徙的旅程，同时依靠向量或真正的导航策略，并通过消除海流的漂移效应重建海龟与水相关的运动路径。被追踪的海龟在它们的航向方面没有表现出任何重大变化，并且主要面向觅食区。虽然模拟没有提供均匀的结果，但根据运动路径估计的海龟定向效率表明它们可能依赖于向量而不是真正的导航策略。目前的结果表明，矢量导航是一种可行的策略，可以解释在动态海洋条件下迁徙的海龟的迁徙行为，