Influence of Gizzard Shad on Fish Community Ecology in Northeastern South Dakota Glacial Lakes

<p>Walleye Sander vitreus are the most popular sport fish in South Dakota, while yellow perch Perca flavescens are important both ecologically as prey for walleye and economically as an important sport fish themselves. Gizzard shad Dorosoma cepedianum are also an ecologically important species in many of the systems in which they occur. South Dakota is at the northwestern edge of the native range of gizzard shad and overwinter survival of shad is often limited. However, with recent climate warming gizzard shad have been experiencing overwinter survival in some South Dakota systems where it had not been previously documented. This overwinter survival could allow for a natural range expansion of gizzard shad in South Dakota. A resulting range expansion could have a variety of effects on the invaded systems. Walleye would likely prey on gizzard shad, which could increase their growth, condition and abundance. If sufficient gizzard shad are present they may even buffer yellow perch from predation by walleye potentially increasing perch survival and recruitment. However, the extent of competition between gizzard shad and yellow perch is unknown. The objectives of this study were to 1) estimate survival, reproduction and recruitment of gizzard shad in two northeastern South Dakota glacial lakes and 2) determine the impacts gizzard shad on the population dynamic rates and seasonal diets of both walleye and yellow perch in northeastern South Dakota glacial lakes. To determine the effects that gizzard shad had on walleye and yellow perch in northeastern South Dakota glacial lakes I performed whole lake manipulations on two northeastern South Dakota glacial lakes by introducing adult, pre-spawn gizzard shad in two subsequent years. Adult, pre-spawn gizzard shad were collected from Lake Sharpe, South Dakota and transported to East Krause and Middle Lynn lakes, Day County, South Dakota where they were stocked in May of 2008 and 2009. Both lakes are located in drainages where gizzard shad are native. Using a before-after-control-impact study design I monitored a total of three lakes (two treatments, one control; Lardy Lake) over a 4-year time period; 1 year pre-gizzard shad, 2 years with shad, and 1 year post-shad. Survival, reproduction and recruitment were assessed for all three species and growth, relative abundance, condition, size structure, seasonal diets and stable isotope signatures were assessed for both walleye and yellow perch throughout the study. For my first objective, gizzard shad reproduction was estimated through ichthyoplankton surface trawling to develop an index of abundance (number/100 m3). An index of juvenile abundance was developed by estimating the number of autumn age-0 gizzard shad collected during nighttime electrofishing (number of fish/h). Additionally, overwinter survival of adults was assessed by marking all adult gizzard shad stocked in 2009 to differentiate them from adult shad stocked in 2008. Adults were sampled simultaneously with walleye and yellow perch using both graded mesh gill nets and boat electrofishing. Additionally, as no adults were stocked in 2010, any adult or juvenile gizzard shad captured during 2010 would indicate at least some overwinter survival had occurred.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation - University Access Only

Discipline thesis:degree_discipline

Wildlife and Fisheries Science

Year

2011

Author dc:creator

• VanDeHey, Justin Allen

Contributors dc:contributor

• David W. Willis

• Natural Resources and Conservation

Statement dc:rights

• Copyright © 2011 Justin Allen VanDeHey. All rights reserved.

Language dc:language

en

Repository record dc:identifier

https://openprairie.sdstate.edu/etd/586

OAI identifier oai:identifier

oai:openprairie.sdstate.edu:etd-1586