Lake sturgeon suitability modeling , and coverage generation in Pools 5 A and 8 of the Mississippi River

To increase the understanding of lake sturgeon (Acipenser fulvensens) in the upper Mississippi River a radio telemetry study was conducted in Pools 4 through 10. Currently lake sturgeon are listed as a species of concern. GIS analysis of available data was performed to determine the spatial relationships that exist between lake sturgeon and their habitat. Aquatic type, wing dam, revetted dam, and closing dam data were available for Pools 5A and 8. Pool 8 bathymetry data also existed, however interpolation of Pool 5A bathymetric data was necessary to create a bathmetry coverage for that pool. The Pool 8 bathymetry is considerably older (1989-93) than the collected lake sturgeon data used in this suitability modeling study. However, statistical analysis of coverage and field data demonstrated that Pool 8 coverage data were still useful for the purposes of analyses. After the spatial coverages were assembled (location to structure, aquatic type, and depth), habitat suitability modeling was performed to determine if these data could be used to model species habitat. After determining percent available and percent used for each coverage, percent used was divided by percent available. Suitability values were then assigned according to a ranking of these values. GIS and statistical analysis were then used to determine habitat suitability for lake sturgeon in portions of Pools 5A and 8. Stepwise linear regressions were performed on coverage data in Pools 5A and 8, and these analyses ranked the habitat factors used in the suitability model in order of importance. For the determination of spatial relationships between fish and aquatic structures (closing, revetted, and wing dams), UNIX ARC/INFO was used. Various fish species such as bass and walleye exhibit the tendency to be located near aquatic structures, but average distances to these aquatic structures suggests that lake sturgeon do not share that tendency in the Polander Lake area of Pool 5A. Finally, distances analyses to areas of highly suitable habitat were performed. Many lake sturgeon were located in areas of highly suitability. Those not located within highly suitable areas were in close spatial proximity to these areas.