Date Approved


Graduate Degree Type


Degree Name

Biology (M.S.)

Degree Program


First Advisor

Dr. Mark Luttenton

Second Advisor

Dr. Carl Ruetz

Third Advisor

Joseph Feldhaus


The lower Muskegon River is one of the most heavily fished rivers in the state of Michigan and is a valuable component of the multi-billion dollar sport fishery in the Great Lakes. Although significant stocking effort has been invested to maintain and improve the steelhead (Oncorhynchus mykiss) fishery in the Muskegon River, natural recruitment has been severely limited due to high summer water temperatures. The goal of this research project was to evaluate the success of a diffuser system installed in 2008 at Croton Dam to moderate high summer water temperatures in the lower Muskegon River. I estimated natural juvenile steelhead abundance, survival, and production in the Muskegon River and compare that with previous work to see if there has been a population level response to the installation of the diffuser. In addition, I used heat shock protein analysis to confirm whether juvenile steelhead are experiencing thermal stress in the Muskegon River.

First, I used water temperature data from the USGS gauging station on the Muskegon River from 2006-2008 and 2010-2012 to compare stream temperatures before and after the installation of the diffuser. Based on the summary of the mean monthly average temperature, temperatures in August remained similar before and after the installation of the diffuser even though temperatures in July 2010-2012 were 0.8⁰C higher than July 2006-2008. Based on the results from this study, stream temperatures in the Muskegon River do not appear to have improved since the installation of the diffuser.

Pass depletion surveys were used to estimate parr survival, production and growth in the Muskegon River and Bigelow Creek during 2011-2013. Average fall density of parr in Bigelow Creek was 48-fold higher than in the Muskegon River. Average summer daily mortality rate of parr in the Muskegon River was nearly six-fold higher than in Bigelow Creek. High mortality rates in the Muskegon River corresponded to average summer water temperatures exceeding 21⁰C. My results were similar to previous work completed on the Muskegon River and suggest that natural steelhead production in the Muskegon River is still severely limited due to high summer water temperatures.

The final object of this study was to investigate whether juvenile steelhead in the Muskegon River and Bigelow Creek are experiencing thermal stress as a result of high summer water temperature using fin tissue to conduct heat shock protein analysis. I found that there were significant differences in fin heat shock protein 70 (hsp70) levels across sites and seasons. Relative hsp70 levels for each site in August varied significantly from June and October at all of my sites, except for one site in Bigelow Creek, which had lower summer water temperatures. Collectively, these results suggest that juvenile steelhead in the Muskegon River are still experiencing prolonged exposure to elevated temperatures and thermal stress, which result in physiological consequences that could ultimately affect the survival of naturally reproducing steelhead in the Muskegon River.

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