Benthic and Nektonic Studies of Winyah Bay for the Proposed Channel Deepening Project and Dredging of the Western Channel Turning Basin

摘要

Benthic and nektonic studies of lower Winyah Bay and its entrance channel were conducted during October 1980 in order to determine the composition of the Fauna and to assess the potential impacts of proposed dredging operations on the biota. Three replicate grab samples were taken at each of 12 benthic sampling sites located either within, or adjacent to, the existing channel to Georgetown. In addition, qualitative samples of the epibenthos were taken with a modified oyster dredge. Hydrogaphic analyses of bottom water samples indicated that salinities ranged from mesohaline to euhaline. Salinities in the former two reaches fluctuated considerably between tidal stages, ranging from mesohaline at low tide to euhaline at high tide. The natural stress imposed by such a highly variable salinity regime accounts for the low species richness and faunal abundances. The occurrence of oyster shell rocks at certain stations in lower Winyah Bay provided a number of microhabitats for a variety of sessile and motile epifaunal species. The only differences in faunal composition between channel and bank stations which could reasonably be ascribed to an impact from previous dredging operations, was found at channel station CW03. A temporary reduction in fishes and crustoceans may result form the removal of benthic organisms which constitute the major food resource for demersal fish and crustaceans. Abundance would be expected to return to pre-dredging levels as the benthos recolonized denuded substrates.