DNR To Eliminate Injurious Fish At 3 Area Lakes

The Iowa Department of Natural Resources (DNR) has announced its plan to eliminate injurious fish species at Folsom Lake in Mills County and Scott Lake B and Lake Virginia in Fremont County.

The DNR plans to treat water in the three lakes with Rotenone, a botanical pesticide, in an effort to kill the fish population.
Two of the lakes - Folsom and Scott B - are so-called “borrow lakes” created more than 50 years ago during the construction of Interstate 29. Missouri River flooding in 2019 introduced rough fish into the two lakes, displacing nearly all sport fish. The most recent fishery survey indicates the lakes are now inhabited by common carp, silver carp, shortnose gar and black bullhead.

DNR Fisheries Management Biologist Bryan Hayes said these injurious fish species reduce water clarity, destroy aquatic plants and prevent the fishery from reaching its full potential.

Lake Viriginia, located in Waubonsie State Park, suffered winter kill earlier this year. Winter kill, similar to what happened at Glenwood Lake Park, occurs during prolonged periods of ice and snow cover that depletes oxygen from the water.

“Surviving fish, including black bullheads and common carp have gained the upper hand at Lake Virginia,” Hayes said.

Rotenone has been commonly used for nearly a century to manage fish populations and improve water quality.

Hayes said after the fish populations have been eliminated, the DNR will stock the three lakes with largemouth bass, bluegill and channel catfish - probably in the spring of 2022. Catchable-size fish are expected to be in the lakes by 2023.