More changes are coming to regulations for Lake Mille Lacs in an effort to restore a healthy walleye fishery, according to DNR Fisheries Chief Don Pereira, who delved into the issue during the DNR Roundtable last Friday.

The lake is flush with larger walleyes, but missing are strong younger year-classes of the species, a required ingredient to ensure balance and the future of the fishery.

“There seems to be not as many of them surviving to age one,” said DNR researcher Melissa Drake.

Pereira said figuring out why is the key to fixing the problem. The DNR is committed to finding a solution, he said.

“It’s a very special place, but it’s a bit beleaguered now,” said Pereira, who has a cabin not far from the lake. “We’re in a tough spot.”

Pereira acknowledged that past DNR walleye regulations, namely the size selectivity of both the state and tribal fisheries, have contributed to the problem.

“Fisheries management certainly has had something to do with this,” Pereira said. “When we, way back in the 1990s, developed the very first control rules for managing both the state fishery and the band’s fishery, we used the best available information … and we went forward in a very uncertain world and put our best foot forward. We’re finding out now that wasn’t the best way to do it.”

Pereira said it initially was believed that the fishery could sustain a 24-percent annual harvest of walleyes, but emerging evidence suggests that number is likely too high.

Pereira declined to discuss what this spring’s Mille Lacs walleye regulations might look like, as meetings that determine them have yet to occur.

Last year, drastic changes were put in place, dropping the bag limit from four walleyes to two, and only allowing fish between 18 and 20 inches to be kept, though one could be over 28 inches. Previously, the slot protected fish between 17 and 28 inches, with one fish allowed over 28 inches.

Pereira said the DNR is forming a “blue ribbon committee” of walleye experts to work at bringing back the walleye fishery. He’s already contracted experts from Michigan State University’s Quantitative Fisheries Center to sit on the committee, as well as Paul Venturelli, who is now a faculty member at the University of Minnesota and completed noted research on walleyes at the University of Toronto. There’s also Nigel Lester, of the Ontario Ministry of Natural Resources, who has agreed to join the panel.

“It’s going to take a while to get the system back in a good spot, and the system is very complex,” Pereira said.

Part of the complexity involves a number of factors, such as what role other predators are having, and the lakes increasing water clarity. Clearer water generally is associated with lower production.

And while zebra mussels, which have been in the lake for a numbers of years and are also known for filtering water and increased water clarity, Pereira noted that Mille Lacs was beginning to become clearer before zebra mussels arrived, likely what he called, the “unintended consequences” of the federal Clean Water Act of 1972.

On the table are not just walleye regulations, but also potentially further loosening of the regulations regarding Mille Lacs’ other game fish species, such as smallmouth bass and northern pike, which have been flourishing in recent years and could be partly responsible for the low survival rates of young walleyes. Last year, the lake’s northern pike protected slot was narrowed to 33 to 40 inches (it was 27 to 40 inches the year before), and a 17- to 20-inch protected slot was created for smallmouth bass, with a possession limit of six. Before, all smallmouths under 21 inches had to be released, and only one could be kept.

Pereira said there may be further room to increase harvest of northern pike, but more intensive field work has been started to try to figure out how culpable those other predators may or may not be, he said. Aside from a tagging study of these species, there’s also an intensive diet study under way, looking at what these fish are actually eating.

“If you like walleyes, but you don’t like smallmouth bass, right away you want to think, ‘Oh, the juvenile mortality problem is because there are too many smallmouth bass in the system,’” Pereira said. “We don’t really know that. We’ve got to get the information. If we want to move forward with the best information, we have to go out and get it.”

The DNR also has hired a new Brainerd-based biologist to try to figure out which predators are eating walleyes and how many they’re eating.

That will include walleyes, which some believe has created “a buildup of eating machines.”

But Pereira said other lakes, such as Winnibigoshish, have shown an ability to maintain good numbers of young walleyes while protecting the larger, trophy-sized walleyes.

He also said that just stocking more walleyes was not a solution, since reproduction of walleyes is not really the problem. It’s that the young walleyes aren’t surviving the juvenile stage at a high enough rate.

“Stocking more fish on top of those will not benefit the population,” he said.

“The goal is to improve the Mille Lacs walleye fishery as expediently as possible with as little negative impact to the community as possible,” Pereira said.

So why are we, NAs included, all

targeting the same year class?

 

Photo courtesy of the Wisconsin Department of Natural Resources