Exelon’s nuclear power station in Cordova, Illinois, has conducted a fisheries monitoring program since 1973 to identify any potential measurable impact that the Quad-Cities Generating Station cooling water intake and discharge may have on the fishery of Mississippi River Pool 14.
Their program has evolved into a comprehensive assessment of the Pool 14 fishery population and has become an important source for fish and mussel stocking operations.
Exelon’s monitoring program includes a study of the life history and population dynamics of several sport and commercial fish species including freshwater drum, channel catfish, flathead catfish, walleye and sauger. Ninety-four fish species have been collected in Pool 14 during the 41-year monitoring program.
Different species are captured depending upon the technique used. Those species caught most abundant by electro-shocking were bluegill, largemouth bass, freshwater drum and gizzard shad. Channel and flathead catfish were collected by hoop nets while bluegill, black crappie and white crappie were collected in haul seines. Unusual fish species collected included American eel, lake sturgeon, brook trout, lake trout and the only recorded long-nosed sucker ever caught in the Upper Mississippi River.
Exelon’s fish stocking program began in 1987 with a total of 4.2 million stocked in Pool 14 and 1.2 million stocked in Pool 13. In 2013, there were 164,134 walleye stocked in Pool 14 and 34,152 walleye stocked in Pool 13. Fish also are stocked into Pool 12, the Rock River, and multiple other sites throughout the greater Quad-Cities area.
Each spring hatchery personnel collects up to 15 pounds of local walleyes. After the fish spawn at the hatchery, all are returned to the river. And there are pictures, so those 12 to 15 pound walleyes aren’t fish stories.
Based on the numbers of marked fish collected in population surveys, 33 percent of walleye collected at Lock and Dam 13 and 38 percent of walleye collected at Lock and Dam 14 were attributed to the Quad-Cities station supplemental walleye stocking program in 2013. Most years the survey shows somewhere between 25 and 35 percent of the walleye are hatchery fish. These high numbers of walleye provide excellent sport fishing opportunities and attract many tournaments.
The hatchery also produces alligator gar, blue catfish and Higgins-eye mussels for other conservation projects with partners including the Illinois Department of Natural Resources and U.S. Fish and Wildlife Service. The mussels are a federally endangered species and are being placed in Pool 15 for a restoration project. The alligator gars are released into Illinois River backwaters between Havana and Beardstown. Blue catfish are released in other Illinois power plant lakes.
The fish stocking program was developed to supplement those fish killed by impingement in the nuclear power station’s water intake. Impingement is when fish cannot swim away from the screens and become pinned to the screens due to the current pushing against them. Most fish impinged are small and not able to swim against the current or are dead or dying. The water intake is like a small vacuum and also collects fishing lures, swimsuits and other debris.
During 2013, there were 52 species of fish impinged totaling an estimated 509,907 individuals. Gizzard shad account for about 80 percent, followed by freshwater drum at 8 percent, channel catfish at about 5 percent, and 3 percent bluegill.
Jeremiah Hass, fish biologist for Exelon, will conduct a presentation detailing the walleye, mussel and other species propagation and stocking programs. An electro-shocking demonstration will show how brood stock fish are collected. The presentation will occur at 1 p.m. today at the Rock Creek EcoTourism Center.
Ed Britton is a wildlife refuge manager for the Upper Mississippi River National Wildlife and Fish Refuge and a volunteer at the Bickelhaupt Arboretum.