Assessment of Crappie Population Demographics in Three Midwestern Reserviors

Crappie provide important sport-fisheries throughout the United State.  Due to their propensity to display growth stunting, assessment of crappie population demographics is needed in Midwestern Reserviors.  We assessed the population demographics of white crappie Pomoxis annularis in three Illinois reservoirs and black crappie Pomoxis nigromaculatus in one reservoir.  Samples were collected by three-phase AC boat electrofishing in Lake Mattoon, Lake Charleston and Paradise Lake, Illinois.  All crappie were weighed (g), measured (mm), and the otolith was removed for age estimation along with scale samples.  Relative density was measured by catch per unit of effort.  Size structure of white crappie between reservoirs differed among reservoirs (p < 0.0001) with Lake Mattoon having the largest mean and Paradise Lake having the smallest mean length.  Additionally, we found crappie condition differed among reservoirs (p < 0.0001) with Lake Mattoon having the greatest mean relative weight.  Our results indicate one population of white crappie is displaying growth stunting.  Management recommendations were made to alter minimum length requirements.