Species associations and community structure in an oceanic elasmobranch assemblage

A 26-year underwater visual survey of elasmobranchs at Cocos Island National Park reveals significant shifts in community structure and species associations, highlighting the dynamic nature of marine predator assemblages. The study identified a transition from a sparse, low-diversity network in the early 1990s to a more densely connected assemblage by 2014, with distinct seasonal sub-communities: migratory oceanic species during the wet season and resident coastal species in the dry season. Scalloped hammerhead (Sphyrna lewini) and whitetip reef sharks (Triaenodon obesus) were key drivers of these changes. Negative associations among species suggest complex predator-prey dynamics and intraguild competition, with three distinct patterns—competition, predation, and environmental preference—explaining interspecific interactions. This research advances understanding of elasmobranch community evolution in oceanic ecosystems.

Gómez García, M. d. J., Moll, R. J., Hearn, A. R., Espinoza, M., & White, E. R. (2026). Species associations and community structure in an oceanic elasmobranch assemblage. Marine Ecology Progress Series, 779, 1–13. CLOCKSS. https://doi.org/10.3354/meps15053