Largemouth Bass Response to Habitat and Water Quality Rehabilitation in a Backwater of the Upper Mississippi River

Abstract

Abstract Severe sedimentation since lock and dam construction in the 1930s has reduced water depth in Upper and Lower Brown's lakes, a backwater complex in Pool 13 of the upper Mississippi River, and resulted in periods of chronic anoxia. This backwater complex was rehabilitated by construction of a deflection levee, installation of a water control structure, and excavation of canals through the area. Water quality variables inside and outside the project area, movement of radio-tagged largemouth bass in response to changing oxygen concentrations, and creel statistics were used to evaluate the success of the improvements. Turbidity was significantly less in the Brown's Lake complex than in the main channel. Oxygen concentrations were allowed to deteriorate to 3 ppm before the water control structures were opened during the winter; within 7 d, oxygen concentrations as high as 10 ppm were found in the top strata in most of the Brown's Lake complex. Chemical and thermal stratification observed in the dredge ...