Document Type

Thesis - Open Access

Award Date

2017

Degree Name

Master of Science (MS)

Department / School

Natural Resource Management

First Advisor

Michael Brown

Second Advisor

Brian Blackwell

Keywords

fall electrofishing, recruitment, South Dakota, walleye

Abstract

Because of the popularity of Walleyes and the need for recurrent supplemental stockings, substantial resources are allocated to their management in eastern South Dakota. For nearly 20 years, fall night electrofishing has been used to monitor age-0 Walleye population parameters, and index future year-class strength in select waters but with limited evaluation. Additionally, knowledge of recruitment patterns and factors that influence those patterns were of interest. Thus, the objectives of this study were: 1) to determine the utility of fall electrofishing age-0 Walleyes to index future year-class strength; 2) to explore whether measures of fall age-0 body size or condition are related to Walleye recruitment; 3) to identify Walleye recruitment patterns and explore recruitment synchrony; and 4) to examine the influence of select abiotic and biotic variables on Walleye recruitment in eastern South Dakota natural lakes. Long-term data sets were used to assess Walleye recruitment. Spearman correlations were used to evaluate the ability of age-0 Walleye fall night electrofishing to index year-class strength (age-2 CPUE) and explore relationships between recruitment, age-0 mean TL (standardized to 15 September), and condition. While high age-0 CPUE’s did not ensure strong recruitment to age 2, positive correlations identified for most lakes suggests that fall night electrofishing provides a coarse, but useful index of recruitment in eastern South Dakota natural lakes and should be continued. Meanwhile, correlations used to examine relationships between age-0 Walleye fall size or condition and recruitment yielded few significant results, and thus provided little additional information in terms of indexed year-class strength. In a subset of lakes, Walleye recruitment patterns were assessed and an information-theoretic approach was used to evaluate the influence of select abiotic and biotic predictor variables on recruitment. Walleye recruitment was highly variable within and among lakes from 1998-2013 and fluctuations in recruitment were generally nonsynchronous. While much of the variation in Walleye recruitment remained unexplained, model selection results supported adult Northern Pike Esox lucius relative abundance and reduced models that included winter severity. Although relationships were weak, lower Walleye recruitment was generally associated with higher Northern Pike relative abundance and increased winter severity.

Library of Congress Subject Headings

Walleye (Fish) -- South Dakota.
Recruitment (Population biology) -- South Dakota.
Electric fishing.

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

128

Publisher

South Dakota State University

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Rights Statement

In Copyright