Imagine heading out on the Waupaca Chain O’ Lakes and finding walleye nearly 30 inches long that tip the scale at more than 9 pounds.
Al Niebur and Dan Nelson have been there and done that.
Niebur, the area’s longtime state Department of Natural Resources fisheries biologist, and Nelson, a DNR fisheries technician, spent much of April on the Chain surveying the lakes’ walleye population for the first time since 2011.
“We’re trying to get a population estimate on the walleye,” Niebur said. “The different dynamic this time around is we’ve been stocking large fingerling walleye. There are two year-classes from 2011 and 2012 that should be showing up in our survey now. We’re trying to look at the survival on those stocked fish and see how fast they’re growing.”
The DNR last year unveiled the Wisconsin Walleye Initiative as a way to increase the number of walleye by expanding production of large fingerlings at state, private and tribal fish hatcheries for stocking in waters accessible to the public.
“We’re trying to evaluate the effectiveness of that especially here, because this is kind of a stocked fishery,” Niebur said. “There’s potential here to get some natural reproduction here through the spawning areas. That’s another thing we’re going to be looking at, too.
“The other thing we’re doing with this survey is we set some nets for other fish,” he said. “We set a few nets for northern pike. We’re probably not doing a population estimate with those fish, but we’re looking at size structure and catch rates to see how it compares to the last time we did a survey. We catch a lot of bluegill, crappie, pumpkinseed, rock bass. We can look at the size of those fish as well.”
Niebur and Nelson recently headed out to check eight fyke nets placed along the shorelines on several lakes of the Chain, including Columbia, Rainbow and Beasley.
“Because of the species that we’re targeting, there are certain habitats they’re using for spawning and that’s where we’re setting these nets,” Niebur said. “For northern pike, we’re targeting the shallow, vegetated bays that warm the fastest. They like to spawn in emergent and submergent vegetation. It has to be areas that aren’t really exposed to wind action, the quieter areas.
“For walleye, we set nets on rocky shorelines, anywhere there’s cobble of gravel substrate,” he added. “Those are the areas they’re going to be spawning on. In the Chain, it’s primarily Rainbow, Sunset, Columbia (lakes) where we see the walleye spawning.”
After finding several small bluegill, a few hefty rock bass, some large painted turtles and several zebra mussels in the first net near the Wisconsin Veterans Home, Niebur and Nelson found what they were looking for at their second stop: a large female 28-inch walleye that weighed more than 9 pounds.
While Niebur collected information and wrote it down, Nelson measured and weighed a number of large walleye and removed a spine from a fin.
The pair also counted and measured other fish found in the nets.
“Why do we do these surveys?” Niebur said. “You go to the doctor and say you get a physical every year or every two or three years to see how you’re doing. It’s the same thing with our surveys. We have all our lakes that have public access on rotation. This is one of our high-use, high-profile lakes that we survey every four years.”
Walleye didn’t turn up at every stop, but Niebur and Nelson found several fish.
“I have to crunch the numbers, but I’d say I expected to see a few more walleye,” Niebur said. “I suspect that some of these fish that we stocked back in 2011 and 2012 haven’t reached maturity yet. Perhaps in our next netting cycle, we might see more of those coming in. It is going to be a low-density population because it’s a stocked fishery.”
The DNR placed the nets in early April while there while some of the Chain was still covered with ice.
Niebur and Nelson returned in late April with boom shockers.
“What we’re basically doing is checking on the size of the fish and the density of fish as far as their abundance,” Niebur said. “We do that with different techniques depending on the species of fish. Now, we’re using fyke nets to target northern pike and walleye because they’re spawning right now. It’s easy to get those fish because they’re up in the shallows. After we’re done, we’ll use a boom shocker that uses electricity. That’s very effective at targeting largemouth bass. We also use that as an index to look at our panfish population as well.”
The DNR is also looking at recently drawn-down lakes in Weyauwega, Iola and Marion this year.
“We’re going back and doing a quick one-night shocking survey just to see how they’re doing,” Niebur said.
The Chain will be surveyed again in 2019.
“We’ll be back again in four years and repeat the process,” Niebur said. “One of the interesting things about our surveys is they’re all standardized. We pretty much follow the same methodology and we can track trends in the lake itself. Other biologists do their surveys the same way, so I can compare the Chain to other lakes.”