The fish population of Lake Columbia, a 36.42 ha Mississippi impoundment, was estimated by shoreline seining, mark and recapture, rotenone sampling and gill netting. The impoundment was then drained to evaluate results. Shoreline seining provided an excellent estimate of population balance. Mark and recapture oflargemouth bass (Micropterus salmoides) gave a statistically valid estimate and was the only method to which statistics could be applied. Length-frequency data of bass from rotenone samples were stable and appear useful, although large bass were underestimated. Rotenone samples gave stable balance ratios, but standing crop varied greatly. Gill nets captured all major species and provided useful data on species not adequately represented in rotenone samples.
