Eight species of bacteria, 8 genera of parasites, and I species of virus were found infecting rainbow trout (Salrno gairdnen), brown trout (S. trutta), brook trout (Salvelinus jontinalis) and yellow perch (Perca jlavescens) from 2 locations in the Chattahoochee River below Buford Dam. There were no clinical signs ofdiseases caused by these potentially pathogenic organisms. Microscopic lesions were present in some of the fish, and the gill was the organ most often affected. These lesions were probably caused by a chemical in the water, but it was not possible to identify the chemical with the results of this study. There were fewer lesions in the fish collected at the downstream station compared to the fish collected near the dam, possibly a result of higher dissolved oxygen concentrations downstream. Lesions were more common following increases in iron and manganese concentrations in the water, but additional water quality data and information on fish diseases in the Buford Dam tailwaters must be obtained before reasons for the poor fish health can be determined.
