Document Type

Thesis - Open Access

Award Date

2023

Degree Name

Master of Science (MS)

Department / School

Natural Resource Management

First Advisor

Alison Coulter

Abstract

Fish require a variety of resources including prey, thermal refugia, and different physical habitat characteristics to grow and reproduce. All necessary resources are rarely provided by a single habitat, resulting in tradeoffs between occupying different habitats; therefore, the ability to move among heterogenous habitats is critical. These tradeoffs may occur in lakes with connected wetlands where the main lake habitats tend to be more thermally stable, but wetlands often provide more diverse and abundant prey. For my second chapter, I compared prey diversity and abundance as well as Walleye (Sander vitreus) diets and condition in a large glacial lake (Lake Kampeska, South Dakota) with a connected wetland to better understand seasonal changes in the benefits provided by each habitat. I examined seasonal differences (spring, summer, and fall) between habitats through two years (2021 and 2022). The prey fish community was more diverse and abundant in the wetland, and Walleye consumed more prey (by weight) in the wetland during all seasons except spring. In my third chapter, I documented seasonal movement patterns of wetland use for Walleye in Lake Kampeska. I used observed movements and environmental data to inform a bioenergetics model to understand the effects of wetland use on fish growth. Walleye used the wetland more when the lake was warm and similar in temperature to the wetland, and Walleye crossed between habitats more often when temperatures were similar. Bioenergetics models indicated Walleyes grew more when they spent more time in the wetland, particularly in summer and fall, but I found no energetic benefit of frequent between-habitat movements. Wetland reconnection may be an effective tool for managers to increase sportfish growth and achieve a common management objective of providing desirable-size fish to anglers. By understanding the energetic tradeoffs that seasonally alter fish habitat use, managers can prioritize the locations and timing of wetland access for fishes. However, fish species vary widely in their seasonal resource and habitat requirements, so maintaining surface water connections among a diversity of habitats may be important in supporting a diversity of fishes.

Library of Congress Subject Headings

Walleye (Fish) -- Environmental aspects.
Walleye (Fish) -- Seasonal distribution.
Walleye (Fish) -- Feeding and feeds.
Wetlands.
Glacial lakes.

Publisher

South Dakota State University

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Rights Statement

In Copyright