Prey resource use by bluegill and channel catfish in small impoundments

Abstract  Channel catfish, Ictalurus punctatus (Rafinesque), are commonly stocked into small impoundments that contain bluegill, Lepomis macrochirus Rafinesque, and these species may compete for food resources because both prey on macroinvertebrates. Prey selectivity and diet overlap of sympatric bluegill and channel catfish were evaluated in two small impoundments. Both fish species fed primarily on macroinvertebrates; but diet overlap between the species generally was not extensive because channel catfish consumed a more diverse array of foods, including more crayfish, fish and plant material. The use of foods other than macroinvertebrates increased as channel catfish grew larger. Bluegill also ingested large quantities of plant material at times, and ingestion of plants increased with fish size. Results of this study suggest that food competition between bluegill and channel catfish may occur when small channel catfish are abundant because, like bluegill, they feed almost entirely on macroinvertebrates and may reduce macroinvertebrate abundance. Thus, overstocking channel catfish in small impoundments managed for bluegill should be avoided.