ECOLOGY OF AEROMONAS-HYDROPHILA IN A SOUTH-CAROLINA COOLING RESERVOIR

Densities of Aeromonas hydrophila were determined monthly from December 1975 to December 1977 in a South Carolina cooling reservoir which receives heated effluent from a single nuclear production reactor. Selected water quality parameters and prevalence of red-sore disease among largemouth bass were monitored simultaneously. Higher densities of A. hydrophila were observed in areas of the reservoir receiving effluent from the reactor. Densities of A. hydrophila generally were heterogeneous in the water column. The sediments had lower densities of A. hydrophila than water immediately above. A. hydrophila could not be isolated from sediments greater than 1 cm from the water interface. Temperature, redox potential, pH, and conductivity were all significantly correlated with densities of A. hydrophila in the water column. The temporal and spatial distribution and abundance of A. hydrophila in water were not related to total organic carbon, dissolved organic carbon, particulate organic carbon, inorganic carbon, or dissolved oxygen. High densities of A. hydrophila were observed in mats of decomposing Myriophyllum spicatum and, enterically, in largemouth bass, several other species of fish, turtles, alligators, and snails. The greatest densities of A. hydrophila in water occurred during March and June with a second peak in October. The mean monthly densities of A. hydrophila were positively correlated with the incidence of infection in largemouth bass. Largemouth bass from thermally altered parts of the reservoir had a significantly higher incidence of infection. It is concluded that thermal effluent significantly affects the ecology of A. hydrophila and the epizootiology of red-sore disease within Par Pond. © 1979 Springer-Verlag New York Inc.