Small-scale patterns of nekton use among marsh and adjacent shallow nonvegetated areas of the Galveston Bay Estuary, Texas (USA)

Rozas, L.P.
Zimmerman, R.J.
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Nekton and infaunal densities were quantified and compared among vegetated and shallow nonvegetated areas of upper Galveston Bay and East Bay, Texas during 1993 and 1994. The vegetated marsh surface consistently contained more species and total numbers of decapod crustaceans than nonvegetated areas. In contrast, fish species richness and densities of total fishes on the marsh and in nonvegetated areas were not significantly different in most comparisons. Most numerically dominant species of nekton seemed to exhibit at least some degree of habitat selection. Within vegetation, elevation and proximity to open water, were most important in influencing the distribution of nekton. Overall, marsh-surface and adjacent nonvegetated habitat types contained much higher densities of most nekton than the shallow bay. Infaunal densities were estimated from sediment cores, and taxa were most abundant in nonvegetaed areas contiguous with marsh in the spring. Factors that influenced infaunal abundance are complex and may include predation, flooding patterns, elevation, and distance to edge. This study has important implications for designing marsh-creation projects. Based on the results, it is recommended creating a variety of marsh and contiguous shallow-water areas to enhance nekton biodiversity. To maximize fishery habitat, priority should be given to constructing low marsh edge by creating large areas of low marsh interspersed with a dense network of shallow channels and interconnected ponds.

p. 217-239
nekton, marshes, habitat improvements