A physical fish barrier fence, made of horizontal bars, was installed in 2012 at the Big Creek spillway to reduce adult walleye and muskellunge escapement from Big Creek Lake. The barrier was a collaborative project between the Central Iowa Anglers, Recycled Fish, the U.S. Army Corps of Engineers and Iowa Department of Natural Resources.
“We observed a substantial loss in muskellunge abundance in Big Creek Lake from 2007 to 2010. This loss coincided with flood events over several years,” said Ben Dodd, Iowa DNR fisheries biologist. “We were studying walleye during that time frame and were also interested in increasing the walleye density in Big Creek.”
Fish escapement increases costs and makes it difficult to maintain fish populations through stockings, like walleye and muskellunge at Big Creek Lake. Escapement also makes it difficult for biologists to manage a lake for a certain density or population size.
“A combination of increased stocking rates and the barrier have allowed walleye and muskellunge populations to rebound at Big Creek Lake. Biologists across the state have expressed interest in installing this style of barrier at other lakes; however, we lack data on the barrier’s effectiveness,” said Dodd. “We’re fairly confident that older, larger fish are not leaving the system but we’re not sure about the younger fish. We’re also interested in testing alternative barrier designs to ensure we are constructing the most effective barrier. “
A collaborative research project between the Iowa Department of Natural Resources, U.S. Army Corps of Engineers and Iowa State University has begun to evaluate the barrier at Big Creek Lake. Iowa DNR Fisheries staff has been installing automated readers at the Big Creek Lake and Brushy Creek Lake spillways. The automated readers will detect tagged fish as they pass over the spillways. The Brushy Creek Lake spillway does not have a barrier, but will serve as a control lake since it is similar to Big Creek Lake.