The Topeka shiner (Notropis topeka) is Minnesota's only federally endangered fish species, listed in 1999. A species of special concern in Minnesota, it has only been found in the Rock River Watershed. Reasons for its decline are not fully understood and basic understanding of habitat needs and life history have been lacking. This study was initiated to gain a better understanding of this species and factors affecting its status. Objectives of the study were to develop habitat suitability curves (HSC) and habitat versus discharge models for Topeka shiners in the Rock River Watershed. Results from this study will be incorporated into recommendations for streamflow and habitat protection for the Rock River Watershed. The Minnesota Department of Natural Resources (MNDNR) Stream Habitat Program is developing recommendations for streamflow and habitat protection for each of Minnesota's 39 major watersheds. These recommendations are being developed using the Instream Flow Incremental Methodology (IFIM) (Bovee et al. 1998). The IFIM, developed by the U.S. Fish and Wildlife Service, is the most widely used method for addressing instream flow issues (Reiser et al. 1989). The Physical Habitat Simulation System (PHABSIM), a group of computer programs within the IFIM, combines hydraulic simulation procedures with species-specific habitat suitability criteria to predict changes in available physical habitat with changes in flow (Milhous et al. 1981; Milhous et al. 1989). Habitat suitability criteria describe the preference of an aquatic organism for the variables water depth, mean column water velocity, substrate, and cover. These flow dependent physical habitat features play a vital role in governing the distribution and abundance of stream fishes and macroinvertebrates (Hynes 1970; Aadland 1993; Hart 1995). Because changes in flow translate into changes in these habitat features, stream flow regulation can adversely affect the structure, function, and composition of stream communities by altering the availability of various habitat types on both spatial and temporal scales (Cushman 1985; Bain et al. 1988; Sparks 1992).
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Minnesota Water Research Digital Library