Research seeks answers to declining fishing on the Missouri River after 2011 flood

Biologists continue to tag and track walleye and wiener in the Missouri River and Lewis and Clark lakes between the Fort Randall and Gavins Point dams as part of an effort to understand declines in fishing following historic flooding in 2011.

Since 2021, 201 fish have been tagged in the river and reservoir as part of a fish movement study. The fish sport metal tags on their jaws, but they also have acoustic transmitters implanted in their abdomens. Fifteen receivers spaced every 5 miles throughout the system record any fish that pass within half a mile. So far, 44 fish have been caught and 39 harvested. Two fish have been caught three times.

A walleye with a metal tag in its jaw is being tracked as part of a study to understand declines in the walleye and sausage fisheries in the Missouri River and Lewis and Clark Lake between the Fort Randall and Gavins Point dams after floods in 2011.

The biologists hope to use this information to help determine why fishing has declined in the reservoir since 2011, when months of high flows dumped many fish through the Gavins Point Dam. The loss included emerald glitters, the main forage base in the reservoir, which has not been recovered. Neither are walleye, despite the fact that more than 100 million fingerlings and fingerlings have been stocked since 2014.

Will Radigan, the University of Nebraska-Lincoln graduate student doing fieldwork for the project, said the study so far has shown that about 25 percent of the nearly 200 fish tagged move less than a mile, while that 10% have moved more than 60 A fish tagged in May 2022 below Fort Randall Dam moved 66 miles downstream to Gavins Point Dam in September, turned around and returned upstream and was caught in April near from where it was marked.

Two walleye and two sausages have passed through the Gavins Point Dam, a fact that is suspected to be part of the problem facing the fishery. Radigan is also sampling fish larvae in the spillway below the dam and found that during peak hauling, more than 20,000 fish per hour pass through the dam. More than 90% are freshwater drums, which are now the main forage base in the reservoir, but walleye and wieners are also moving through the dam.

The biologists used nets, electric fishing, and hook and line to capture a sample of fish from different reaches of the river, the reservoir, and the delta at its upper end. They even enlisted the help of Mike Hamsa from Yutan, a fishing guide for The Walleye Guys, who helped catch 56 fish to tag.

A few more fish will be tagged next spring and monitoring will continue through 2025.

Jaw tags are stamped with a three digit number. Anglers catching these fish are asked to call their state conservation agency to report the tag number. If they catch the fish, they are asked to retrieve the transmitter and return it as well.

In Nebraska, anglers must report tag numbers to the Northeast District Office in Norfolk at 402-370-3373.

Partners in this research project include the Nebraska Park and Game Commission, South Dakota Game, Fish and Parks, and the University of Nebraska-Lincoln School of Natural Resources.