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Document Type

Thesis - University Access Only

Award Date

2015

Degree Name

Master of Science (MS)

Department

Natural Resource Management

First Advisor

Melissa R. Wuellner

Abstract

Walleye Sander vitreus is the most popular game fish among South Dakota anglers. Accordingly, substantial resources are invested in walleye management. However, recruitment of walleyes to the recreational fishery is often unpredictable due to various biotic and abiotic factors. In addition to knowing what factors can promote or inhibit recruitment, it is also important to have a reliable index of young-of-the-year walleye that may help predict adult recruitment. Therefore, the objectives of my study were to: 1) Determine the optimum stocking rate of fry and small fingerling walleye for South Dakota natural lakes and examine whether extrinsic factors influence variability in adult walleye recruitment; 2) Determine which sampling methods may be used to reliably index spring age-1 walleye relative abundance; and 3) Determine whether size selective overwinter mortality is occurring by examining pre- and post- winter walleye body size and condition. Age-2 walleye recruitment was highest at stocking densities of 2,040 fry/ha and 191 small fingerling/ha. Stock-recruitment models without the addition of environmental variables were the most supported candidate models for both stocking products, but candidate models that also included adult yellow perch Perca flavescens relative abundance or an index of winter severity showed substantial support. During spring age-1 walleye gear testing, precision of nighttime electrofishing xi (CV = 216.6) was greater than that estimated for mini-fyke nets (CV = 338.5). No differences in length-frequency distributions of spring age-1 walleye gear were detected between the two gears. Age-0 fall relative abundance indices from electrofishing were significantly greater (P < 0.01) than spring age-1 nighttime electrofishing indices of relative abundance on all four study lakes, indicating overwinter mortality. Quantilequantile regression plots showed evidence of size-selective mortality in three of the four lakes sampled. However, no evidence was shown to indicate that body condition of age-0 walleye influenced mortality. Overall, results of this study provided important insight into optimal stocking rates and factors that affect walleye recruitment and highlighted the complexities of recruitment in South Dakota natural lakes. Ultimately, these results may be used to refine management strategies to enhance walleye recruitment to benefit both anglers and fisheries managers.

Library of Congress Subject Headings

Walleye (Fish)--South Dakota
Recruitment (Population biology )-- South Dakota
Fish stocking -- South Dakota

Description

References on pages 41-45

Format

application/pdf

Number of Pages

69

Publisher

South Dakota State University

Rights

In Copyright - Educational Use Permitted
http://rightsstatements.org/vocab/InC-EDU/1.0/

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