Smallmouth Bass Long-Term Assessment

We are currently monitoring Smallmouth Bass populations in several Illinois rivers, with a focus on providing information needed to address low abundances in the Mackinaw River following a decline circa 2000.

Our objective is to evaluate the status of wild and stocked Smallmouth Bass in the Mackinaw and Vermilion rivers, map substrate throughout their lengths, and track the movement of Smallmouth Bass in the Mackinaw River. Analyses based on these three types of data will allow us to;

1) assess the abundance and condition of the native and stocked population within the rivers,

2) provide detailed underwater habitat mapping based on side-scanning image data in both rivers, and

3) assess movement and habitat utilization in the Mackinaw River.

Together these analyses can identify potential factors limiting population abundance in the Mackinaw River. Results of our studies will be shared with the Illinois Department of Natural Resources to improve management of Smallmouth Bass fisheries in these rivers and rivers throughout the state.

Region map displaying the watershed boundaries of the two river basins being studied for smallmouth bass populations, the Mackinaw River (blue) and Vermillion River (green). Both rivers are tributaries to the Illinois River.