Nebraska Game and Parks Commission and University of Nebraska-Lincoln biologists are starting a five-year study of juvenile fish survival in irrigation reservoirs to improve fishing.
The study includes Swanson Reservoir near Trenton, Enders Reservoir near Imperial, Red Willow near McCook, Medicine Creek Reservoir near Cambridge, and Harlan County Reservoir near Alma and Republican City, which are all within the Republican River watershed. They were built primarily for flood control and irrigation, and are characterized by large fluctuations in water levels.
The reservoirs also provide important fisheries for anglers in southwest Nebraska. Walleye and white bass are especially important sport fish in these reservoirs. However, annual stockings of walleyes have been necessary because natural production has been low. Further, white bass natural production has been extremely variable.
“We believe that a bottleneck exists for production of walleye and perhaps white bass in these irrigation reservoirs,” says Dr. Kevin L. Pope, assistant leader of the Nebraska Cooperative Fish and Wildlife Research Unit housed at the University of Nebraska- Lincoln who heads up the study. “The purpose of this project is to gain an understanding of the factors affecting natural production of walleye and white bass.”
This study has several components. The first component will be documenting the relative importance of spawning habitats for walleye and white bass in the southwest Nebraska reservoirs. To accomplish this task, researchers will surgically implant adult fish with tracking devices this fall. In spring, researchers will follow these fish to their spawning grounds. If an angler catches a fish with a wire protruding from its body it is an indication that the fish is carrying an internal transmitter and biologists ask that the fish be returned unharmed to the water. If for some reason the fish dies, the angler is asked to return the transmitter to the nearest Commission district office.
The information that will be gained through this study is vital to biologists understanding fish ecology in irrigation reservoirs.
