Complexity in a facilitative behavior web of piscivores and associated species at Isla del Coco National Park (Eastern Tropical Pacific)

Discerning the role that facilitative behavioral interactions in mixed species groups of hunting piscivores play in growth and survivorship is important both in our fundamental understanding of fish community dynamics and for developing conservation strategies. In this study we collected data on mixed-species hunting groups (species composition, numbers, behavioral interactions) and used both multivariate and network analyses to quantify pair-wise and guild level behavioral relationships. Our results demonstrate that collective behaviors in mixed species hunting groups exhibit consistent patterns of associations within a set of dominant species (10 of 32 species within the network) and are a common attribute of this functional guild within the shallow fish community at Isla del Coco (to 80 m depth), Pacific Costa Rica. Indeed the removal of only a few dominant species from the behavior web model, to simulate overfishing, reduced the number of pair-wise linkages by 57% (32 species with 282 pair-wise links to 28 species with 122 links). The identification of these patterns, assuming they are persistent features of these communities, can be used as a foundation for time-series monitoring to assess status and change in ecological interactions within the higher trophic level guild of fishes. That said, more work is needed to understand the temporal dynamics of network linkages and intensity of interactions as prey resources vary in distribution and abundance. Such information could be used to interpret the nature of multispecies interactions within predator communities and serve as an aid in conservation and management.