The Effects of the Stronach Dam Removal on Fish in the Pine River, Manistee County, Michigan

Although dam removal has been increasingly used as an option in dam management and as a river restoration tool, there are few studies providing detailed quantitative assessment of the response of fish populations to dam removal. In this study, we document the response of the fish community in the Pine River, Michigan, to the gradual removal of Stronach Dam. Ten sites were sampled annually during the course of the removal (1997-2003) and for 4 years following removal (2004-2007). Before the removal of Stronach Dam, 11 fish species were found only downstream of the dam, 1 species was found only upstream of the dam, and 19 species were captured both above and below the dam. Following removal, 8 species formerly found only below the dam utilized newly available portions of the river above the dam. Most fish species (18 of the 25 evaluated) showed an increase in abundance following removal, strongly supporting the idea that dam removal reduces multiple factors limiting riverine fishes. Brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss were the primary sport fishes present in the river, and the abundance of both species increased by more than twofold over the course of the study. The abundance of white suckers Catostomus commersonii also increased significantly due to increased reproductive success. The results of this study illustrate how dam removal is a useful tool for restoration of habitat connectivity and habitat conditions and how the fish community in a coldwater stream responded to the removal.