Robert Fisher

Date of Graduation

Summer 2013

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Daniel Beckman

Abstract

The main objective of this thesis project was to determine if there was an effect of habitat on centrarchid species population density. Seven sites on the James River, Missouri were sampled two times each using a backpack electroshocker. Centrarchids were identified and measured. Habitat was measured. Macroinvertebrates were collected. Catch per unit effort (CPUE) was calculated for each centrarchid species, and principal component analysis (PCA) was performed on the habitat data. An index of biotic integrity (IBI) was calculated from the macroinvertebrates collected. The Kolmogorov-Smirnov two-sample test was used to test for differences in length-frequency distributions and χ2 test was used to test for differences in fish species abundance. The CPUE for centrarchid species varied among species and among sites with longear sunfish Lepomis megalotis having the highest CPUE. The PCA identified two components, bank vegetation and substrate complexity, that accounted for most of the habitat variation. Most sites with high fish density were sites with higher bank vegetation and substrate complexity; however, in general, habitat measures did not provide a reliable predictor of fish density. No significant differences were found in centrarchid length-frequency distributions among sites. The χ2 test results indicated a trend in differences in fish abundance among sites with greatest differences in sites separated by greater distances. The IBI results placed 3 sites in the non-biologically supporting category and the other 4 in the partially biologically supporting category. The change in centrachid species abundance changed between sites could be from the changes in habitat.

Keywords

CPUE, habitat, centrarchid, IBI, population

Subject Categories

Biology

Copyright

© Robert Fisher

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