North American Journal of Fisheries Management 15:754-765, 1995 © Copyright by che American Fisheries Society 1995 Population Characteristics of Black Crappies in South Dakota Waters: A Case for Ecosystem-Specific Management

Abstract.—We sampled 22 populations of black crappie Pomoxis nigromaculatus from three ecosystem types (large impoundments,>40 ha; small impoundments, <40 ha; natural lakes) to determine the factors that influence population characteristics (recruitment, growth, size structure, and condition) in South Dakota. Recruitment variability was best correlated with the logio of the shoreline development index (r = 0.63, df = 16) and the log to of the watershed: lake area ratio (r- 0.89, df = 12). Mean back-calculated length at age was highly variable among ecosystems and was inversely correlated with the log!0 of the catch per unit effort (CPUE; r =-0.35 to-0.69). Mean back-calculated length for all ages was positively correlated with mean relative weight (r = 0.48-0.78, df = 18-21). Proportional stock density and relative stock density of preferred-length fish were inversely correlated with Iog10 CPUE (Spearman correlation, rs =-0.31 to-0.83, df = 21) and were positively correlated with growth of black crappies (rv = 0.55-0.73, df = 18-21). Bivariate centroids differed significantly (P ̂ 0.05) among ecosystems for canonical analysis; canonical factor scores were derived from growth, recruitment, CPUE, and condition. These data suggest that black crappie population characteristics differ among ecosystems. Natural lakes typically had black crappie populations with low density, unstable recruitment, fast growth rates, and high condition factors. Conversely, small impoundments had black crappie population