Improving Indices of Abundance for Gray Snapper in Eastern Gulf of Mexico Estuaries: Results from Four Years of Habitat-Based Sampling of Polyhaline Seagrass Beds

Gray snapper support extensive recreational fisheries in estuarine and coastal waters throughout the eastern Gulf of Mexico.  Because gray snapper exhibit an estuarine-dependent life history, it is possible to estimate the relative strength of juvenile recruitment to the estuary which is critical for the effective assessment of the population. Prior evaluation of multi-year fisheries-independent monitoring data collected within Florida Gulf coast estuaries indicated that gray snapper appeared to inhabit polyhaline seagrass beds that were underrepresented in ongoing monitoring efforts. Accordingly, additional habitat-based monitoring effort, designed to target seagrass habitats, was implemented.  Shoal and deep-water polyhaline seagrass habitats were sampled with 183-m haul seines and 6.1-m otter trawls, respectively.  The frequency of occurrence, catch-per-unit-effort, and size structure of gray snapper collected from long term monitoring and new polyhaline seagrass surveys were compared.  This recent (2008 - 2011) habitat-based sampling on polyhaline seagrass habitats resulted in increased catches and reduced variability in abundance indices for gray snapper within each estuarine system, resulting in reductions in the coefficient of variation of annual recruitment indices.  Continued sampling of polyhaline seagrass habitat is recommended to improve our ability to detect changes in the relative abundance of gray snapper through time.