Sponge (Porifera) Fauna Portrayal in the Foraging Area of the Hawksbill Turtle from Martinique: Applying Integrative Taxonomy

Martinique sponge fauna was largely undocumented until 2017, when the first inventory of Porifera colonizing coral reefs, mangroves and caves around the island was published. We performed an integrative classification of sponges in the foraging area of hawksbill turtle (Eretmochelys imbricata) in Martinique. Sponge specimens were retrieved as direct or indirect diet items consumed by hawksbill turtles after video observations, and the feeding behaviors of these predators were tracked. Morphology was supplemented with molecular identification (DNA barcoding) based on a multi-locus approach using COI, 28S and ITS genetic markers. Seventeen different species were identified, belonging to seven orders: Poecilosclerida, Dictyoceratida, Verongiida, Agelasida, Haplosclerida, Clionaida, and Tetractinellida. Haplosclerida exhibited the greatest diversity and species abundance, followed by Verongiida. The 28S marker provided the highest confidence in species identification. We provided new barcode records for Hyattella cavernosa and Amphimedon caribica. Among the cataloged sponges, only four of them had been previously reported as food items of E. imbricata (Xestospongia muta, Iotrochota birotulata, Spirastrella coccinea and Cinachyrella kuekenthali). The rest represent newly documented items that are potentially preyed upon by this turtle predator. The characterization of sponges as being part of the feeding habitat of hawksbill turtles underpins management and protection plans for this critically endangered species, and the benthic community on which they feed, by providing criteria for generating networks of Marine Protected Areas (MPAs) in the Caribbean regions.