Feeding Ecology and Activity Rhythms of the Critically Endangered Hawksbill Turtle

The critically endangered hawksbill turtle (_Eretmochelys imbricata_) is a keystone species that, through its decline, has a profound effect on marine ecosystems such as coral reefs. This study aimed to characterize the activity rhythm and dietary preferences of hawksbill turtles in Martinique to develop appropriate conservation strategies at both local and global scales. Six individuals (one female and five males) were monitored using on-board cameras. Findings show that hawksbills spend more than half of their time feeding at a depth of 14.43 ± 9.72 m, especially in the morning. Video recordings revealed consumed prey, including plants and animals, and these were identified to the family level. Habitat sampling revealed potential prey from six distinct families. Video recordings (selected prey) and habitat samples (potential prey) were compared to indicate prey selection. Aplysinidae was the most frequently observed family both as consumed and potential prey. Aplysinidae and Irciniidae, both marine sponge families, represent new records in the hawksbill diet. Spongin content and brominated metabolites are proposed among the plausible factors that could define turtle food preferences and strategies. Further combined analyses could help to better define feeding strategies as an integrative and collaborative approach, which is essential for the long-term protection of this critically endangered species.