Richness and distribution patterns of elasmobranchs in the San Andres, Providencia and Santa Catalina Archipelago: is this area a hotspot of these species in the greater Caribbean?

Abstract

Hotspots identification can be used to establish protected or priority areas for conservation at different geographic scales. We aimed to determine if San Andres, Providencia and Santa Catalina Archipelago could be considered as a hotspot of elasmobranch diversity within the Greater Caribbean. For that, we updated the elasmobranch species richness and analyze its distribution pattern, evaluated the assembly structure and composition and estimated the occurrence probability of the more abundant species of the Archipelago. A total of 46 species, 33 of sharks and 13 of batoids were recorded, with 8 categorized as threatened by IUCN. Quadrants of San Andres and Providencia islands presented the highest richness with 16 species. Oceanic environments differed significantly in composition and abundance from the other four large areas evaluated. Northern banks were the most favorable environments for large-sized pelagic sharks while San Andres and Providencia Islands were for batoids; this difference could be due to the pelagic and benthic habits, respectively, and their relation with availability of substrate, food and sheltered areas. Our study confirmed that the Archipelago has at least 21% of the total richness of the northwestern Atlantic region, 43% of that of the Greater Caribbean and 49% of that registered in the Colombian Caribbean Coast, suggesting that the Archipelago is a potential richness hotspot in the Caribbean region. This high elasmobranch diversity could be due, among others, to its status as a Biosphere Reserve, to its high diversity of habitats and more recently to the establishment of the shark fishing ban.