(Radio Iowa) – The Iowa Department of Natural Resources is nearly ready to start a project to get rid of an invasive species of fish in an 830 acre lake in northwest Iowa. Mike Hawkins, a fisheries biologist with the D-N-R, says weather over the past two years delayed the effort to rid West Swan Lake in Emmet County of common carp.

“Both of those winters we tried to draw the lake down, get it to winter kill,” Hawkins says. “Last winter we tried to help a little bit with a chemical that helps renovate fisheries. We were not successful. We had the warmest winter on record last winter. We had a very short window for pulling that project off.” Common carp feed on the bottom of lakes, make the water murky and cause problems for other species of fish.

“We’re going to try this one last time this fall,” Hawkins says. “We’re going to do an open water treatment if we can get the water levels down far enough and kill off those carp.” West Swan Lake levels were elevated by this year’s flooding.  “We need the lake down about three, three-and-a-half feet,” Hawkins says. “It’s all just mathematics and how much of the chemical we have available and the logistics and the expense of doing that.”

Hawkins says one side of the lake has dropped enough and they’re waiting for the water level on the other side to fall and match it. West Swan Lake is the last in a small chain of natural lakes and marshes that eventually flows into the west fork of the Des Moines River. Hawkins says regardless of the outcome of the carp eradication effort, West Swan Lake will be restocked in the spring with Northern Pike, Yellow Perch, Blue Gills and Largemouth Bass.