Predictive habitat suitability models to aid the conservation of elasmobranchs in Isla del Coco National Park (Costa Rica)

Abstract

Worldwide there is increasing concern for elasmobranch species given that their biological and ecological characteristics make them highly vulnerable to fishing pressure. The disappearance of these species could affect the structure and function of marine ecosystems, which would induce changes in trophic interactions at the community level. For effective conservation and management of elasmobranchs detailed knowledge of their habitat preferences is essential. Yet, there is a poor understanding of their spatial ecology. Isla del Coco National Park is an oceanic island in Pacific Costa Rica and renowned for being a sanctuary for migratory pelagic species, such as elasmobranchs and other non-migratory species. However, the abundance of many of these species has been rapidly declining over the last decades as a result of overexploitation (legal and illegal fishing). Within this context, Generalized Additive Models were performed to investigate the environmental preferences of eight elasmobranch species in Isla del Coco National Park using six predictors (i.e., sea surface temperature, salinity, chlorophyll-a concentration, bathymetry, distance from the coast and slope). Results demonstrate similar habitat preferences based on distance from the coast, slope and chlorophyll, which indicates that elasmobranchs prefer shallow waters near the island with varying degrees of slope. This study helps to identify both some of the hotspots for elasmobranchs biodiversity in Isla del Coco National Park. This approach provides an essential and relatively easy tool, such as predictive distribution maps, to increase our knowledge of marine habitats in Isla del Coco to better manage them and other offshore marine protected areas.