Managing Walleyes On Puckaway & Big Green

Located just a couple miles apart, Big Green Lake and Lake Puckaway couldn't be more different. Big Green, which covers 7,325 acres, is our state's deepest lake, with a maximum depth of 237 feet. Puckaway, at 5,500 acres, is one of our shallowest big lakes, with a maximum depth of only 7 or 8 feet.

Big Green is clear, cold and slow to warm up in spring. It has what biologists call a "two-story" fishery: lake trout and ciscoes in the deeper water, and walleyes, pike, bass and panfish in the shallower water. Weed growth is limited to the shallow bays and shoreline areas.

Puckaway is a wide spot in the Fox River, which enters the lake at its west end and exits at the east end. Warm, dark and fertile, Puckaway is highly productive. It supports good numbers of largemouths, northern pike, walleyes and panfish.

Carp are present in both lakes. On Puckaway, they were so numerous that they destroyed most of the aquatic vegetation and roiled the water, making life difficult for other fish species. A carp-control program was started there in 1979 when the lake was poisoned and restocked with game fish. On Big Green, carp destroyed vegetation in some shallow bays, most notably the Spring Creek inlet at the lake's east end, which was historically a walleye spawning area. Commercial fishermen are contracted to remove carp from both lakes, and barriers have been installed at both ends of Big Green to keep carp out of sensitive areas.

The outlet of Big Green is the Puchyan River, which enters the Fox well downstream of Puckaway. Department of Natural Resources fisheries biologist Dave Bartz of Montello says walleyes may have moved from one lake to the other historically, but he believes dams prevent any mixing of the two populations today. Genetic studies have confirmed that these are two distinct populations. Because of this, and because the lakes are so different, each requires a different management approach.

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Al Walker and Joel Baranowski from the Green Lake Chapter of Walleyes For Tomorrow check a fyke-net catch. (Photo by the Wisconsin DNR)

MANAGING BIG GREEN

"Big Green has always been a low-density walleye lake," said Bartz. Typical of deep, cold lakes with a two-story fishery and a ciscoe population, it produces big fish, but not great numbers of them."

Bartz says walleyes once ran up Silver Creek and spawned near Ripon, but today most walleyes spawn in the lake, which can be problematic.

"A deep lake like Big Green has wide temperature fluctuations in spring," Bartz said. "Under ideal conditions, walleye eggs hatch in seven to 10 days. If an onshore wind blows cold water into an area where walleyes have spawned, the eggs may sit on the lake bottom for three weeks or more before they hatch."

The longer incubation period can subject the eggs to greater dangers, such as predation and smothering by filamentous algae, which has covered rocks in shoreline areas in recent years. Once they hatch, the tiny fry have to contend with white bass, ciscoes, rock bass and other fish that have no trouble finding them in the clear water. As a result, Bartz said, natural reproduction is low and fry survival rates are poor.

Despite the low walleye densities, walleye fishing is popular on Big Green, although the lake has a reputation of being tough to fish. Local anglers have pushed for walleye stocking on Big Green since the early 1990s. Because this is a unique population, Bartz did not want to bring in fish from anywhere else. "We told them the only way to do it was to use the Green Lake fish as brood stock," he said.

And so the Green Lake Chapter of Walleyes For Tomorrow (WFT) stepped in to help manage walleyes there. Since 1999, the chapter has netted spawning walleyes each spring, raised up to 7.5 million fry per year in a portable hatchery and released them in the lake. In 2000, they also raised and released about 12,000 fingerlings. Bartz documented an increase in walleye numbers in 2002, but was unable to do so during spring and fall electrofishing surveys in 2003 or 2004.

The WFT chapter, under the leadership of Al Walker and Joel Baranowski, wants to keep raising fry, but Bartz would rather see them put more effort into raising fingerlings, which have a much better survival rate.

At first, the WFT volunteers simply scatter-planted fry in the open lake, where they are extremely vulnerable to predation. Now that the local sanitation district has installed carp barriers and the lake district has limited weed cutting, the chapter plants their walleye fry in the Silver Creek inlet, where they find both food and shelter from predators.

"We know something is coming from our efforts, although we can't prove it because we haven't kept an accurate record of our catch per effort," said Baranowski. "In our first two years, we handled maybe 100 or 200 fish. Last year, we handled 600. The last year there was a good natural hatch was in 1993. Those fish are now 23 inches long and longer. The fish we think we are responsible for are males under 16 inches and females between 17 and 22 inches. We've been seeing a lot more of those in the last two years."

Walleye densities are likely to remain low on Big Green, but Bartz is optimistic the lake will continue to produce big fish. He is planning to survey the walleye population there as soon as the ice goes out this spring. Until recently, the walleye season here was open year-round. Now, the season is closed in March and April to protect spawning fish.

"It's too early to tell what impact the WFT work has had," Bartz said. "But we should get an idea when we put our nets in this spring. If anything is happening on Big Green, it is just beginning. We should know more in a couple more years."

MANAGING PUCKAWAY

In recent years, walleye fishing on Lake Puckaway has been nothing short of fantastic. Walleye numbers have increased dramatically, thanks to a successful fry-stocking program and to natural reproduction. "We stock fry every year and have documented good fry survival," Bartz said. "There's a new WFT chapter there that has a portable hatchery going, and natural reproduction has taken off, too."

Lake Puckaway warms up early in spring and does not suffer the wide temperature fluctuations that play havoc with the walleye spawn on Big Green Lake. Walleye eggs hatch quickly, and fry find food and protection in the dark, nutrient-rich water.

Puckaway is part of the Winnebago Chain, and prior to the building of dams along the river over a century ago, fish likely moved freely throu

ghout the system. The DNR removed one dam upstream of Puckaway and one downstream of the lake in the last several years. More than a decade ago, the boil below the Eureka dam was filled with rock to create a riffle and a fishway was constructed. A dam near Princeton still blocks the passage of Winnebago walleyes in most years, but tag returns indicate some fish still make it from one lake to the other. The DNR is negotiating a management plan with Lake Puckaway residents that will include guidelines for regulating water levels in the lake.

Some walleyes spawn on riprap along the lakeshore. Others spawn in flooded marshes above and below the lake. Some run up as far as the Buffalo Lake dam at Montello, but the DNR has never documented any fry from those eggs making it back downstream to Puckaway. In most years, there is not enough current flow to move them down to the lake before they absorb their yolk sac, so they starve before they reach the lake.

The DNR, in conjunction with the local WFT chapter, is improving shoreline spawning habitat in the lake and river, Bartz said. "We did riprap work on the Fox near the site of the old Grand River dam, and plan to do more at the site of the White River dam," Bartz said. "We also plan to put more rock on the old dredge bank that was built when the lake was deepened for navigation."

Walleyes are doing well enough on Puckaway that crews take spawn there every year for hatcheries at Wild Rose and Lake Mills. Now that three dams have been removed or broached, walleye movement through the system should continue to improve. Bartz plans to continue work on spawning marsh habitat on the river in the next few years. A spring survey planned for 2006 should give him a good picture of how well walleyes have responded to stocking efforts and habitat work.

You'd be hard pressed to find two lakes more different than Big Green and Puckaway. Fortunately for the anglers who fish them, a group of dedicated professionals and volunteers is working hard to maintain viable walleye populations on these neighbors whose challenges differ, but whose outlooks are equally promising.