Population Demographics Of White Crappie In Three Illinois Reservoirs

Abstract

Crappie provide important sport-fisheries throughout the United States. Because
of the propensity of this species to display growth stunting, an assessment of crappie
population demographics is needed in Midwestern reservoirs. I assessed the population
demographics of white crappie, Pomoxis annularis, in three Illinois reservoirs. Samples
were collected by three-phase AC boat electrofishing. All crappie were weighed,
measured, and the otolith and scale samples were removed for age estimation. Relative
density, as measured by catch per unit of effort (CPUE; fish/hour), was different at Lake
Mattoon (0.53±0.15), Lake Charleston Side Channel Reservoir (1.17±0.15), and Paradise
Lake (1.04±0.18). Size structure of white crappie differed among reservoirs (KS=0.199,
p<0.001) with Lake Mattoon having the largest mean length and Lake Paradise having
the smallest mean length. Additionally, I found that crappie condition differed among
reservoirs (F=33.54; p<0.001) with Lake Mattoon having the greatest mean relative
weight. When modeling growth using von Bertalanffy models, Lake Charleston Side
Channel Reservoir exhibits the lowest theoretical maximum length (Loo) when aged with
both otoliths (241.2 mm) and scales (239.7 mm) while Lake Paradise exhibited the
highest Loow hen aged with both otoliths (431.5 mm) and scales (413.1 mm). Lake
Charleston Side Channel Reservoir also exhibits the lowest annualized mortality rate at
13%. Because Lake Charleston Side Channel Reservoir exhibits the lowest growth rate,
lowest mortality rate, and highest CPUE, it can be concluded that Lake Charleston Side
Channel Reservoir is displaying growth stunting.

Date of Award	2012
Original language	American English
Awarding Institution	Eastern Illinois University
Supervisor	Robert E. Colombo II (Supervisor)