Great lake for walleye

Anglers can find plenty of keepers on Lake Koshkonong

Fort Atkinson-If you're looking for some good walleye action, try Lake Koshkonong.

"The reality is that walleye fishing in southern Wisconsin can be tough," said Gary Wroblewski, a guide who has fished Koshkonong for ten years. "This is a lake where you can catch walleyes. You're going to catch other fish, too. You never know what's at the end of your line. But every once in a while, you'll catch a nice walleye."

Lake Koshkonong is a 10,460-acre lake in southwestern Jefferson County, with a maximum depth of just seven feet.

According to Don Bush, regional fisheries supervisor with the Department of Natural Resources at Janesville, Koshkonong was transformed from a deep-water marsh to a big, shallow lake by the Indianford dam on the Rock River, which was completed in 1917.

"Walleye is probably the most highly sought-after fish," Bush said.

The state stocks walleyes in Koshkonong to supplement a natural population. "We estimate that about 25% of the walleye fishery is stocked and 75% is natural," Bush said.

Koshkonong has had a carp problem for decades, and stocking of game fish is tied to carp removal. Private contractors, supervised by the DNR, take an average of about two million pounds of carp out of the lake each year.

Carp get into the lake from the Rock River, which flows through Koshkonong. Game fish and panfish are stocked to prey on carp and occupy the habitat they would otherwise use.

"The lake, itself, is prime habitat for carp - big and shallow with a muddy bottom and abundant lake fly larvae," Bush said. "That food is also the bread and butter for walleyes, catfish, panfish and white bass."

Typically, the lake gets about three million walleye fry a year but, this year, 500,000 one-inch walleye fingerlings were stocked. "We've had enormous success with fry stocking," Bush said. "We're trying to get a cost-benefit analysis of the fingerlings."

The DNR has re-established a sauger population and is trying to do the same with yellow perch and flathead catfish. The state also stocks between 500,000 and 2 million northern pike fry a year to supplement a natural population, plus about 2,500 muskies.

In addition, the lake has naturally reproducing populations of white bass, largemouth bass, some smallmouth bass, channel catfish, bullheads, black crappies and bluegills.

Watersport Boat Rental, 723 E. Ellendale Road, Town of Newville, has two fishing boats with outboards for $65 a half-day or $85 a day, plus tax and gas. A $200 credit card security deposit is required.

Major boat landings are located off Charlie Bluff Road on the southwest side of the lake, Keuhn and Carcajou Roads on the north, North Shore Road on the northeast and Vinnie Haha Road on the southeast.

"If people have large boats, they're probably better off launching in the river," Bush advised. The DNR has free launches on the Rock River, off Groeler Road under the Highway 26 bypass, east of the lake; and about a mile downstream from I-90 in Newville, southwest of the lake.

Wroblewski, of Eagle, Larry Awe, of Wauwatosa, and I paid $4 to launch at the Riverfront tavern on Blackhawk Island - one of several additional private landings - and motored out to mid-lake on a recent cloudy evening with shifting winds and weather fronts moving through.

"Koshkonong is almost always better when it's windy," Wroblewski said. "I think wind increases the feeding activity."

Don't look for any sharp drop-offs, rock bars or other major structure.

"The lake is pretty much a big flat, so you look for changes from muck to sand bottom and subtle differences in depth," Wroblewski explained. "A foot or two change in depth can make the difference."

We set up four trolling rods with line-counter reels and eight-pound monofilament line, and tied on three-inch crank baits, which we set 10 to 12 feet behind planer boards dragged 25 to 35 yards behind the boat.

We trolled at about 2 mph and, for the next five hours, had steady action reeling in a mixed bag of fish. We caught about 25 white bass, 2 northerns, a bullhead, 2 saugers and about a dozen walleyes, up to almost 19 inches long. We released everything but a couple of the walleyes, which we kept to eat.

"You'll likely catch more undersized walleyes than 'keepers,' " Bush said. "But Koshkonong can produce trophies. I've heard of several walleyes in the 27-inch range taken this year."

Call Bob Riepenhoff at (414) 224-2313 or e-mail him at