Northern Prairie Wildlife Research Center
The Red River basin lies roughly in the geographic center of the North American continent, and its fishes have been investigated for more than a century (Woolman 1896). Surveys by several agencies are still being conducted (Goldstein et al. 1994, Topp et al. 1994). Most surveys of fish distribution have focused on only North Dakota streams or only Minnesota streams, and there has never been a comprehensive site-specific study of Red River basin fishes. A study is required because streams within the Red River basin in both states form a common drainage unit and are separated from other streams in both states by drainage basin divides. Further, two published lists of fish species present in the Red River basin do not agree. In their study of the zoogeography of fishes of the Hudson Bay drainage, Crossman and McAllister (1986) listed 75 fish species for the Red River basin in the United States, while Underhill (1989), in his discussion of fish distribution related to Pleistocene glaciation, listed 80 species. Documentation to rectify the discrepancy between the two lists could not be obtained through correspondence by letter with E.J. Crossman, Curator of Fishes, Royal Ontario Museum, Toronto, or personal visits with J.C. Underhill, Curator of Fishes, Bell Museum of Natural History (BMNH), University of Minnesota (UMN), St. Paul.
Warren and Burr (1994) indicated imperilment of several native North American fish species and "widespread and pervasive degredation of aquatic habitats" in the United States. Because of the apparent lack of information regarding factors controlling stream fish distribution in the midwest region and a lack of any comprehensive distributional studies for the Red River basin, the overall purpose of this study was to determine the distribution of stream fishes in the Red River basin based on multivariate environmental gradients of water quality and flow. The specific objectives of the study were to determine 1) the total number of fish species either currently or historically present in the Red River basin; 2) the site-specific distribution of each stream fish species; 3) any significant changes in the distribution of each stream fish species over time; 4) any similarity among streams in the Red River basin based upon fish species assemblages; 5) common species associations of fishes as found in streams in different regions of the Red River basin; 6) the relationship between sub-basin drainage area, stream length, and average annual discharge and species richness of streams; 7) levels of several water quality and flow variables for stream reaches in the Red River basin; and 8) which environmental variables are most important in explaining the distributions of stream fishes in the Red River basin.
Methods of analysis included an extensive review of the literature regarding fish surveys for all streams in the Red River basin in North Dakota and Minnesota, plotting the distribution of each species using a geographic information system (GIS); an extensive review of the literature regarding water quality and flow for sites throughout the Red River basin; and a statistical analysis which directly relates species to environmental characteristics of stream reaches (direct gradient analysis).