DNR Research: Fish Lake Walleye Population Better Than Originally Thought

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Fish Lake’s walleye population is better than biologists thought just a few years ago. (News Tribune file photo)

 

The walleye population on Fish Lake Reservoir north of Duluth is in better shape than biologists had thought.

That’s the news that Minnesota Department of Natural Resources fisheries officials passed along to about 30 people who attended a meeting Tuesday evening at the Fredenberg Town Hall.

Back in 2010, apparent decreasing numbers from electro-fishing sampling of the lake’s young-of-the-year walleyes and historic low walleye gill-net catches had raised concerns among fisheries biologists. But after three years of research and more restrictive walleye harvest regulations on the popular lake, biologists believe Fish Lake’s walleye population is in good shape.

“Electro-fishing surveys are sending false messages about young walleye abundance in the lake,” Dan Wilfond, a DNR fisheries specialist at French River, said Wednesday. “Because of

the poor correlation to adult walleye abundance, we’re thinking about discontinuing or

modifying these electro-fishing surveys on Fish Lake.”We’re thinking about not doing these electro-fishing surveys (in the future).”

Based on concerns over electro-fishing catch rates from 2005 to 2010, along with other changes taking place in Fish Lake, the DNR formed an advisory committee to seek input. Walleye populations appeared to be decreasing. Bluegills and largemouth bass numbers were increasing. The growing season was longer. More aquatic vegetation was evident in the lake. Water levels were varying less in the reservoir.

As a result, the advisory committee recommended, and the DNR in 2012 adopted, an emergency regulation allowing anglers to keep walleyes only between 13 and 17 inches long, with one over 26 inches allowed in a limit of three fish. Before that, the limit had been six with no size restrictions.

The advisory committee also urged the DNR to do research to see if enough spawning size walleyes were present, if their eggs were hatching successfully and if angler harvest was excessive. Through research, DNR biologists found that the number of spawners was comparable to other lakes with good walleye populations (even better than on Lake Winnibigoshish near Deer River), and that egg production was sufficient.

“That told us the adult walleye abundance is pretty good and is probably not a limiting factor,” Wilfond said.

In addition, by stocking chemically-marked fry (just-hatched walleyes) for three years and comparing numbers of stocked fry to naturally produced walleyes, biologists learned that hatch rates of young walleyes were satisfactory. Combined, all of the research points to one thing, Wilfond said.

“It means there’s not a big problem out there with the adult population, egg production or

survival to the first fall,” he said.

The stocking was not done specifically to increase the walleye population but to answer research questions, Wilfond said. No more stocking is planned.

Biologists with the Fond du Lac Band of Lake Superior Chippewa, as well as the DNR, have checked stomach samples from more than 400 different fish of nine species and found no walleyes in them. That indicates, in general, that predation on walleyes likely is not a significant factor, Wilfond said.

On top of that, an excellent walleye year class in 2009 is providing “a lot of 19- to 22-inch fish,” Wilfond said.

“Our strategy is to hold our own until 2020, as anglers should experience some very good angling for walleye over the next several years,” he said.

In 2020, the DNR will perform its next scheduled gill-net survey on Fish Lake to determine walleye numbers and sizes. The agency also will conduct a creel survey in 2020, if budgets allow, to determine angling pressure and angler harvest. Meanwhile, current regulations will remain in place.

Despite being led astray by the misleading electro-fishing sampling six years ago, Wilfond does not regret the subsequent research efforts.
“It was totally reasonable to take the actions we did,” he said. “It’s better to be proactive than reactive. It turns out maybe we were a little more proactive, but that’s better than having a fishery collapse.”