No evidence of increased demersal fish abundance six years after creation of marine protected areas along the southeast United States Atlantic coast

Abstract

Marine protected areas (MPAs) have been used widely as a conservation and fisheries management tool to protect fish and habitats. We used a time series (2001–2014) of underwater videos from submersibles and remotely operated vehicles to determine whether a series of MPAs established in early 2009 along the southeast United States Atlantic coast has increased the number of fish species, density of fished species, or the density of Rhomboplites aurorubens (Cuvier, 1829) compared to adjacent, non-reserve areas. We used univariate and multivariate approaches at two spatial scales (region-wide and MPA-specific) to test for a change in the number or density of fish species inside compared to outside MPAs. Overall, 185 fish taxa were observed from 1021 video transects across all years of the study. We did not observe a higher number of species, density of fished species, or density of R. aurorubens inside compared to outside MPAs, either after region-wide standardization using generalized additive models or for nominal analyses focusing on two (Edisto or North Florida) MPAs. Using non-metric multidimensional scaling and analysis of similarity, we did not observe any change in community structure occurring inside the MPAs that was not simultaneously occurring outside the MPAs, both at the region-wide or MPA-level scale. We did not detect unique changes to the fish community inside MPAs after their creation, which could be due to low statistical power, not enough data post-MPA creation, low compliance rates, or suboptimal MPA shape and size, or some combination thereof. Given their current relatively low abundances, the sampling effort required to effectively assess potential MPA effects for most grouper species is well beyond current or historical levels of sampling.