Abstract
Hard bottom habitats (e.g., corals, sponges, limestone ledges, artificial reefs) are known to support diverse nekton (fish and macroinvertebrate) communities in offshore areas of the Gulf of Mexico, but less is known about the function of these habitats in estuarine systems. Baited remote underwater video (BRUV) systems were developed for and used in seasonal surveys of nekton communities associated with natural and artificial hard bottom in Tampa Bay (2017-2019). Estuarine hard bottom habitats supported unique nekton assemblages that were a mixture of species found among estuarine seagrasses and associated with offshore reefs. Differences in community structure were significant among structured habitats (artificial, natural, and bridge), seasons, and, marginally, by year; these differences were driven by abundance patterns in a few frequently observed forage fishes (e.g., Lagodon rhomboides. Diplectrum formosum) as well as economically important reef fishes (e.g., Lutjanus griseus, Haemulon plumierii) dependent on estuaries in their early life history. Species rarely collected by capture gear during long-term fishery-independent monitoring in the estuary were also documented, including some economically important reef fishes not typically considered estuarine-dependent (e.g., Epinephelus morio). Estuarine hard bottom may provide transitional habitat for reef fishes that are estuary-dependent in their early life history and emigrate to offshore reefs as adults. Results from this study should aid resource managers in prioritizing habitat for conservation and serve as a model for monitoring these habitats in other estuarine systems that have good visibility. Augmenting existing multigear, multihabitat fish surveys to include sampling over estuarine hard bottom would improve the ability to document changes in nekton assemblages, including economically important reef fishes, especially in relation to environmental perturbations.