Using Geographic Information Systems Technology to Model Relationships between Black Bass Abundance and Physicochemical Characteristics in an Oklahoma Reservoir

James M. Long and William L. Fisher
Oklahoma Coop Fish and Wildlife Research Unit, 404 Life Science West,
Oklahoma State University, Stillwater, OK 74078, 404/744-6342, longjm@okstate.edu

We used geographic information systems (GIS) technology to examine relationships between largemouth bass, smallmouth bass, and spotted bass abundance and the physicochemical characteristics of Skiatook Lake, Oklahoma. A GIS was used to generate maps of the physicochemical environment through interpolation of sample data into GIS coverages for subsequent analysis. We then used stepwise multiple regression to examine which of the physicochemical factors affected the relative abundance of each species. Largemouth bass relative abundance was weakly related to decreasing shoreline slope model (R² = 0.06). Smallmouth bass relative abundance was positively related to secchi depth (R² = 0.35). Spotted bass relative abundance was related to increasing shoreline slope and increasing water temperature (R² = 0.27). Although GIS technology enabled us to interpolate sample data to explore spatial relationships between black bass abundance and environmental characteristics in the reservoir, the low explanatory power of the regression models suggests considerable error in interpolated GIS coverages. We recommend that such error be quantified and reported when interpolating reservoir characteristics using GIS.