Distribution of potential spawning habitat for sturgeon in the Lower Missouri River, 2003-06

We surveyed the Lower Missouri River downstream from Gavins Point Dam near Yankton, South Dakota, to St. Louis, Missouri, during low water conditions in 2003-06 to identify and map coarse substrate deposits and bedrock exposures that might serve as spawning areas for sturgeon and other fishes. More than 330 deposits were identified, including tributary fans, bars, and habitat-enhancement projects. The location and extent of riverside bedrock exposures immediately adjacent to the channel also were mapped. Field surveys identified 48 bedrock exposures whereas the analysis of aerial orthophotographs identified an additional 65 exposures for a total of 113. Maps illustrating the distribution of deposits and their density were developed to aid researchers studying reproductive ecology of sturgeon and other lithophilic fishes.