Document Type

Thesis - Open Access

Award Date

2021

Degree Name

Master of Science (MS)

Department / School

Natural Resource Management

First Advisor

Steven Chipps

Keywords

harvest regulations, hooking mortality, mark-recapture, walleye

Abstract

Harvest regulations are commonly implemented to manipulate fisheries stocks. By regulating the size and number of fish that are harvested by anglers, managers are able to meet the goals and needs of regions. However, these management actions come with the potential for negative consequences. Overexploitation due to less restrictive harvest regulations can cause collapses in fisheries populations. In addition, indirect consequences such as hooking mortality brought on by length-based regulations can also be detrimental to populations. In this study, I investigated the effects of various harvest regulations on Walleye populations in three western South Dakota irrigation reservoirs: Angostura, Belle Fourche, and Shadehill. A jaw-tagging study was initiated to estimate angler exploitation in each reservoir. Shadehill had the highest exploitation in 2018 and Angostura had the highest exploitation in 2019. Sagittal otoliths were sampled from Walleye to estimate growth and mortality in each reservoir. Walleye in Angostura exhibited the highest growth rates and highest estimates of mortality. From Fisheries Analysis and Modelling Simulator (FAMS) simulations, yield (kg) was highest for every reservoir when modeled with a 381 mm minimum length limit (MLL). Results from this study reveal that Angostura Reservoir contains a highly productive Walleye population that experiences significant angler exploitation. I also evaluated the effects of capture depth and water temperature on Walleye hooking mortality. The study was split into two angling seasons: an ice fishing season that was conducted on Lake Sharpe and Lake Oahe in February of 2020, and an open water season on Belle Fourche Reservoir in July of 2020. After angling, Walleye were placed into holding pens to monitor post-release mortality. During the ice fishing season, hooking mortality of Walleye was 20%. No mortalities occurred during the open water season. The variables capture depth, fishing season, and air exposure were the most influential variables on mortality. Walleye were generally caught from deeper depths and exposed to air for longer periods of time in winter compared to summer. Results from this study indicate that hooking mortality needs to be considered when implementing length-based regulations, especially in lakes where Walleye angling occurs at depths greater than 10 m.

Library of Congress Subject Headings

Walleye (Fish) -- South Dakota.
Walleye fishing -- South Dakota.
Walleye (Fish) -- Mortality -- South Dakota.
Fishery management -- South Dakota.
Fish populations -- South Dakota.

Number of Pages

81

Publisher

South Dakota State University

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Rights Statement

In Copyright