Shifting elasmobranch community assemblage at Cocos Island—an isolated marine protected area

A significant decline in the relative abundance of eight elasmobranch species, including iconic sharks and rays such as scalloped hammerhead sharks (−45%), whitetip reef sharks (−77%), mobula rays (−78%), and manta rays (−89%), has been documented over 21 years at Cocos Island National Park. Conversely, the probability of occurrence for tiger, Galapagos, blacktip, and whale sharks increased significantly during this period. The study used mixed effects models to analyze data collected by divers, accounting for observer variation and abiotic factors. These findings highlight that marine protected areas (MPAs) may not effectively protect elasmobranch species unless enforcement efforts against fishing are strengthened. The research underscores the importance of tailored conservation strategies that consider life history traits and vulnerability to fishing pressure.

White, E. R., Myers, M. C., Flemming, J. M., & Baum, J. K. (2015). Shifting elasmobranch community assemblage at Cocos Island—an isolated marine protected area. Conservation Biology, 29(4), 1186–1197. Portico. https://doi.org/10.1111/cobi.12478