Food, Growth, and Reproduction of White Crappies (Pomixis Annularis) and Black Crappies (P. Nigromaculatus) in Lake Poinsett, South Dakota

The food habits, food selectivity, growth, condition, and population structures of the white crappies (Pomoxis annularis) and black crappies (P. nigromaculatus) in Lake Poinsett, South Dakota, were studied from May, 1975, to May, 1976. The total food volume of 173 adult white crappies consisted of 59.0% plankton1o crustaceans, 25.2 % insects, 14.5 % fish, and 1.3 % miscellaneous organisms. The food volume of 39 adult black crappies consisted of 39.0 % planktonic crustaceans, 3.5 % insects, 57.8 % fish, and 0.7 % miscellaneous organisms. Both species selected Daphnia pulex over other zooplankton and probably contributed to its decline from 193.8/l on June 27 to 0.0/1 on August 21. Both species preyed indiscriminately on forage fish. Growth rates were comparable to those found in similar temperate lakes. The growth rates of the crappies increased while their population densities declined. The population decline appeared to be due to a lack of spawning habitat caused by low water levels