Assessment of Common Carp Biomass in Rat and Beaver Lake

The Sandhills of Nebraska are a unique ecotone that is home to hundreds of natural lakes. These water bodies are known to be productive and susceptible to inundation from non-native common carp (Cyprinus carpio). Excessive populations of common carp typically require renovation of the system; however, little background has been published on the relationship between catch rate of this species in common gear and the associated density of common carp. The objective of this article is to provide a case study relationship between sampling densities and estimated common carp biomass in hopes that improved clarity will guide future decisions on when renovation management activity may be warranted. The total abundance and biomass of common carp in Rat and Beaver Lake was among the highest reported in the literature. This study found 198.0 common carp per hour of electrofishing corresponded to 1,830 kg/ha. Common carp comprised over 93% of the available biomass in this lake and appeared to limit the other native and sportfish species present in the system. Managers should use the guidelines of this study and the others reported in this article to determine the appropriate time to renovate waters that are inundated with common carp in the Sandhills.