DNR to install carp fence on lake

(Published Saturday, February 26, 2000)

The Janesville Gazette Staff


The Wisconsin Department of Natural Resources plans to install a fence to prevent carp from migrating from Lake Koshkonong to a marsh known as Mud Lake.

Each spring, marauding schools of carp leave Koshkonong and move into Mud Lake, fisheries biologist Don Bush explained in a news release.

In a typical year, several hundred thousand pounds of the exotic fish will wallow in the shallow waters of the marsh on Koshkonong's north end, Bush said. Their rooting activity destroys vegetation, increases siltation and releases phosphorus from the sediments. Precious habitat for small game fish as well as waterfowl is destroyed.

This winter's low water level has left much of Mud Lake dry, and the rest has frozen to the bottom, killing any fish left in the marsh, Bush said.

The DNR intends to construct a 45-foot long fence across the outlet of Mud Lake. The one-inch spacing between the bars in the fence will prevent game fish from entering the marsh, as well, but game-fish fry and fingerlings can be stocked in the lake.

"The expected explosion of vegetation in the marsh should be beautiful nursery habitat for panfish and game fish," Bush says. "During late summer, the grate will be opened to allow fish to move back down out of the marsh and to allow small boats to enter the area."

The project also will involve installing rock riprap on the banks to restore Mud Lake's outlet channel, known as Twin Island Creek. The riprap will repair the channel sides and help confine carp to the stream so commercial fishers can harvest them.

However, poor ice will prevent the riprap from being installed before next winter, Bush said.

Money for the project is coming from the Twin Island Gun Club, The Rock River Koshkonong Association and the Lake Koshkonong Recreation Association. The Mud Lake Sportsman's Club and a small army of volunteers will be installing the barrier.

For more information about this project, contact fisheries biologist Don Bush at the DNR's Janesville Service Center, (608) 743-4823.

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