Common Fishing Effects on Reef Fish Trophic Structure Across Diverse Coral Reef Ecosystems in the Tropical Atlantic and Pacific

One common goal of spatial management of marine resources is to create a refuge for commercially-targeted fishes, both to stabilize or enhance fisheries and help return food webs to a less impacted structure.  Studies in the least disturbed tropical reef systems have found a found remarkable food web structures with greater biomasses of apex predators than the remaining fish assemblage.  We synthesize monitoring datasets from managed areas in the Caribbean, Brazil, the Eastern Pacific and Fiji to compare the structure of fish assemblages across diverse systems and across management regimes.  Using general additive mixed models, we characterize the relationship between the biomass of piscivores and non-piscivores and examine how this relationship interacts with reef systems and management.  We find that piscivore biomass increases linearly with non-piscivore biomass at most reefs but that piscivores constitute increasingly larger portions of the fish biomass in high-biomass studies.  Very few reefs have a higher biomass of piscivores than non-piscivores (inverted trophic pyramids) suggesting that such a food web is not common or easily attained through management.  Relationships between piscivores and non-piscivores vary more across reef systems than across management regimes, suggesting that at sufficiently large scales, fish assemblage structure is more influenced by ecosystem processes than management of fishing activities.