| In Bowman-Haley Reservoir, North Dakota, the fish community became increasingly dominated by large, old, common carp during the first 25 years of impoundment. During this period, submerged vegetation became rare and water quality deteriorated. Despite fisheries management efforts, fishing quality declined. This study was conducted to evaluate methods of carp removal and determine the effects of carp removal on reservoir ecology. Spot-rotenone applications in areas of spawning carp proved to be the most efficient method of removing carp. In 1994 and 1995, approximately 70% of the adult carp were removed from the reservoir. Effects of carp removal on water quality, submerged vegetation, benthic invertebrates, and zooplankton were monitored in areas where carp were eradicated and in areas where carp remained. In areas where carp were eradicated, water clarity, submerged vegetation abundance, benthic invertebrate abundance and richness, and zooplankton abundance increased. In areas where carp were allowed to repopulate, water clarity decreased, submerged vegetation remained absent, and benthic invertebrate abundance remained low. This study showed that high densities of common carp can adversely affect reservoir ecology, impair fisheries management efforts, and impede lake restoration efforts. In lakes and reservoirs with high carp densities, carp removal may be necessary to improve habitat conditions and water quality. |
