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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Wildlife and Fisheries Science

First Advisor

David W. Willis


The relationships between year-class strength of walleye Stizostedion vitreum and sauger s. canadense, as indexed by age-0 seine catch per unit effort (CPUE) , and environmental variables were assessed in Lewis and Clark Lake, South Dakota, from 1985 through 1994. Significant (P≤0. 10) correlations between log10 (n+l) age-0 walleye seine CPUE and environmental variables indicated that some annual and monthly mean daily high and low air temperatures measured at both Gavins Point Dam and Fort Randall Dam, as well as the annual mean daily evaporation from Lewis and Clark Lake were related to age-0 walleye abundance for 1985- 1994. The log10 (n+l) age-0 seine CPUE of sauger was significantly (Ps0. 10) correlated with some annual and monthly mean daily values of discharge out of both dams, storage ratio of Lewis and Clark Lake, mean daily precipitation at both dams, mean daily high and low air temperatures at both dams, and mean daily evaporation from Lewis and Clark Lake. Significant (Ps0. 017) one, two, three, and four variable multiple regression models for both species indicated that air temperature and precipitation likely influenced walleye and sauger year-class strength in Lewis and Clark Lake. This information can be used by biologists to better understand why fluctuations in the year-class strengths of walleye and sauger occur in Lewis and Clark Lake. Cellulose acetate electrophoresis was used to screen muscle and liver samples from 50 Stizostedion individuals collected from Lewis and Clark Lake, South Dakota to determine the extent of hybridization between walleye and sauger and to assess the accuracy of morphological identification. Electrophoretically, 40 fish were identified as sauger, five as walleye, and five as hybrids. Thus, there was a 10% hybridization rate for this sample from Lewis and Clark Lake. Identification based on morphological characteristics significantly (P<0. 05) overestimated the percentage of hybrids compared to the electrophoretic analysis. Morphologically, 34 fish were identified as sauger, seven as walleye, and nine as hybrids. Eight fish (16%) were incorrectly identified using external traits. Because electrophoretic and morphological identification differed, biologists should be cautious when monitoring these fishes or when using wild broodstock from systems in which both species are present. Largemouth Micropterus salmoides and smallmouth M. dolomieu bass sampling data from Lewis and Clark Lake, South Dakota, was assessed to determine if there were spatial, diel, or seasonal differences in CPUE, size structure, condition, and growth. The only significant differences in CPUE occurred for substock-length largemouth bass among reservoir strata (P=0. 002) and stock-length smallmouth bass among months (P=0. 0001). Stock density indices, used to assess the size structure of the largemouth and smallmouth bass populations, did not differ significantly among reservoir strata or diel periods. However, largemouth bass PSD, RSD-P, RSD S-Q, and RSD P-M all varied significantly among months (P<0.001) . Smallmouth bass PSD, RSD S-Q, and RSD Q-P also differed significantly among months (P<0.01). Condition was only found to differ significantly among months for largemouth bass (P=0.03) and smallmouth bass (P≤0.01). Finally, growth rates were only found to be significantly different among strata for age-1 and age-3 smallmouth bass (P≤0.04). This information will help the South Dakota Department of Game, Fish, and Parks design a reliable sampling protocol for these two species.

Library of Congress Subject Headings

Walleye (Fish) -- Lewis and Clark Lake (S.D. and Neb.)
Sauger -- Lewis and Clark Lake (S.D. and Neb.)
Black bass -- Lewis and Clark Lake (S.D.and Neb.)


Includes bibliographical references (page 88-96)



Number of Pages



South Dakota State University


Copyright © 1996 Brian E. Van Zee. All rights reserved.