Disentangling the Effects of Habitat and Protection on Coral Reef Fish Communities in Long-Established Marine Reserves

Marine Protected Areas (MPA) play a central role in policies for the conservation of coastal ecosystems and resources. One of the current challenges of monitoring the effectiveness of MPAs at protecting fish assemblages is distinguishing between the influence of habitat, protection effects and anthropogenic activities. We used strongly spatially-replicated data to investigate these effects within an area comprising two no-take long-established marine reserves. Data were obtained from remote underwater video collected across all habitats in the study area. First, each station was assigned to a habitat based on a multivariate typology of biotic and abiotic cover. A number of metrics including fish abundances, assemblage composition and trophic structure were then modeled as a function of habitat and protection status. We showed that protection effects may be easily detected from a number of metrics involving fished species, but for other metrics, effect detection requires that habitat is explicitly taken into account.