An Assessment of Crappie Stocks in Small Midwestern Private Impoundments

Abstract

Spring trap-netting and electrofishing samples were collected from 11 small midwestern private impoundments by the Central States Small Impoundment Work Group to describe crappie (Pomoxis spp.) population structures in such systems, particularly in relation to largemouth bass (Micropterus salmoides) and bluegill (Lepomis macrochirus). Proportional Stock Density (PSD) of crappie was found to be inversely correlated with largemouth bass PSD and Relative Stock Density of preferred-length largemouth bass (RSD-P). Crappie PSD was positively correlated with bluegill PSD and mean Relative Weight (Wr) of quality-length crappies. There was an inverse relationship between largemouth bass PSD and 8-12-in largemouth bass captured per hour of electrofishing, leading to the presumption that high densities of 15-in and smaller largemouth bass can reduce densities of small crappies and bluegills through predation such that survivors attain sizes of interest to anglers because of decreased intraspecific competition. RSD-P from spring samples was positively correlated with RSD-P according to angler catches for both crappie and largemouth bass. With high largemouth bass recruitment and little or no angler harvest of largemouth bass less than 15 in, a small private impoundment in the Midwest with good habitat and water quality would be expected to produce larger panfish than would exist in impoundments with liberal largemouth bass harvest and/or low largemouth bass recruitment. This management option is appropriate for impoundments where owners and anglers are willing to sacrifice sizes of largemouth bass caught and numbers and sizes of largemouth bass harvested to produce large panfish.