Midwest Fish & Wildlife Conference 2018

AUTHORS. Ridge Sliger, Lee University; Brandan Ward, Point Loma Nazarene University; Cameron Goble, Michigan Technological University; Nancy Auer, Michigan Technological University; Troy Zorn, Michigan Department of Natural Resources; Fred Van Dyke, Au Sable Institute; Marty Holtgren, Encompass Socio-ecological Consulting

ABSTRACT. While the relationships between physical and biological stream conditions and the abundance of popular sportfish such as trout and salmon are extensively studied, the habitat associations and biotic interactions of the small-bodied, non-game species with which they co-occur are often not as well studied or understood. One such species in the Great Lakes basin, the Blacknose Dace Rhinichthys atratulus, has not been widely studied despite being an important species that is often considered an indicator of stream habitat quality. We performed habitat and electrofishing surveys in 21 study sites in the Upper Manistee River watershed located in Michigan’s Lower Peninsula to determine habitat associations of Blacknose Dace. Stepwise multiple regression analyses were performed to determine whether Blacknose Dace abundance correlates with abiotic variables such as water temperature, dissolved oxygen, stream depth, undercut banks, stream velocity, substrate composition, and large woody debris; and biotic variables including Brook Trout Salvelinus fontinalis, and Brown Trout Salmo trutta densities. We hypothesized that Blacknose Dace abundance would be independent of these variables. We found that Blacknose Dace Catch Per Unit Effort (CPUE = number of Dace caught per meter of stream during the first electrofishing pass) was negatively associated with woody substrate and Brook Trout density (fish/m2); and Blacknose Dace density was positively associated with in-stream plant cover, and thalweg depth. These results suggest Blacknose Dace will be more abundant in the Upper Manistee River watershed in areas with little wood cover, low densities of Brook Trout, large amounts of plant cover, and high ratios of pools relative to other geomorphic channel units. Greater understanding of the physical and biological relationships of non-game species such as Blacknose Dace provides insight on frequently overlooked members that play important roles in the trophic structure of the stream community and can serve as indicators of overall stream health.