Dynamics of a Black Crappie Population in a Heterogeneous Cooling Reservoir

Abstract

Abstract Spatial and annual variation in density, growth, and size structure of black crappies Pomoxis nigromaculatus in Lake Wylie, North Carolina-South Carolina, were determined during a 5-year study. Water temperature, turbidity, total phosphorus, and nitrate+nitrite-nitrogen in Lake Wylie varied across zones and years. Significant (P < 0.0001) year or year-class × zone interactions were detected in catch rates, first-year growth, and second-year growth. Significant (P ≤ 0.0002) spatial and year-class effects on first-, second-, and third-year growth were also observed. Black crappies were attracted to the heated effluent of a power plant. First-year growth was correlated (r = 0.55; P < 0.05) with average water temperature during the growing season (April through October). Second- and third-year growth were among the fastest reported in the literature. Second-year growth was faster in areas with higher densities of threadfin shad Dorosoma petenense, which appeared to concentrate in the more nutrient-ri...