Spatial Distribution and Trends in Abundance Of Fishes Residing in Seagrass Meadows on Florida Bay Mudbanks

Fishes inhabiting seagrass beds on shallow mudbanks in Florida Bay were sampled with throw traps, to capture the relatively sedentary, epibenthic species, and gillnets, to capture the more mobile species occupying the overlying water column. There was a strong heterogeneity in species composition and abundances of both components across different subenvironments of the Bay. The Interior section, characterized by a low tidal range and hypersaline conditions, harbored few epibenthic species relative to sites on the periphery of the Bay. Densities of Lucania parva, however, reached outstanding values, with a mean of 39 fish per m² at a West Interior site. Species richness of the water column component was also low in the Interior subenvironment, but a few species had high capture rates, despite salinities of up to 50 ppt. Three years of sampling in the northeast subenvironment indicated a trend from estuarine to marine conditions in salinity regime, seagrass growth, and densities of epibenthic fishes. A conceptual model was developed to aid in understanding the potential role of various biotic and abiotic factors in structuring fish communities on the banks. The distinctiveness of different subenvironments suggests that physical factors of water circulation and salinity patterns play a more influential role in Florida Bay than in more congruous seagrass ecosystems.