Foraging selectivity of the Hawksbill Sea Turtle (Eretmochelys imbricata) in the Culebra Archipelago, Puerto Rico

摘要

Recent literature on foraging in Hawksbill Sea Turtles in the Caribbean region concludes that prey selectivity is a combination of preference for certain prey species and their local abundance. In this study, prey selectivity patterns were measured in five juvenile Hawksbill Sea Turtle (Eretmochelys imbricata) aggregations in the Culebra Archipelago, Puerto Rico, and the hypothesis that juvenile Hawksbill Sea Turtles exhibit selectivity for certain prey items independent of their environmental availability was tested. Hawksbill Sea Turtles showed positive selection for the corallimorph Ricordea florida, which was rare in all four study sites, and for the alga Lobophora variegata, that was abundant in one site. Turtles exhibited low preference for the sponge Chondrilla nucula, the most common prey item in both diet samples and the environment at all study sites. Low preference for this sponge corresponds to its high availability in the environment. Turtles also exhibited low preference for the sponge Cinacyrella sp. and the branching anemone Lebrunia danae. That juvenile hawksbills exhibited strong positive selectivity for rare items indicates that diet selection is not necessarily related to the abundance of the items in the environment. In addition, spatial variability in diet composition among Hawksbill Sea Turtles in the Culebra Archipelago indicates plasticity in their foraging habits.