Date of Award

6-12-2023

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Melissa Wuellner

Committee Members

Keith D Koupal, Paul R Burger, Melissa R Wuellner

Keywords

fingerling;stocking;stocking map;stocking model;walleye;white bass

Abstract

Fish stocking continues to be an important and often-used tool in fisheries management. However, hatchery resources are often limited by funding and space. Therefore, survival of stocked fish is important to improve efficiencies and support important fisheries resources. Various strategies to improve survival have been examined over time, whether in the hatchery or in the waterbody. To improve stocking efficiency, managers should consider potential bottlenecks that could limit the survival of stocked products. To date, previous studies that have considered stocking in relation to these bottlenecks have only considered single factors at one time; however, multiple bottlenecks may be acting within a short time frame post-stocking. To my knowledge, no study has combined potential limiting factors to try to predict where to stock fish in order to support greater survival of stocked products. This study was designed to combine three factors – predator risk, zooplankton (food) availability, and measures of habitat – that could be important to the survival of stocked Walleye and White Bass fingerlings (25 – 50 mm total length) in Lake McConaughy, Nebraska, to create a predictive surface to identify optimum stocking locations. The spatial distribution of each factor was modelled using ArcMap 10.7.1 separately. Then, the three layers were combined into a final stocking layer that identified the best 12.8 and 13.9% of the predicted area of Lake McConaughy for stocking Walleye and White Bass, respectively. Both final stocking layers predicted that locations along the southcentral shoreline of Lake McConaughy were optimal for both stocked species. I hypothesized that predicted stocking locations would change between stocking events but found only subtle differences in predicted stocking locations between the two. Implementation of the conceptual model when making stocking decisions has the potential to increase survival of stocked products and help managers reach population objectives more effectively.

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