Sunday, February 5th, 2023
Sunday, February 5th, 2023

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Northwest conference takes peek at muskie, walleye survival

Hayward, Wis. — A varied group of lake advocates from northwest Wisconsin met recently in Hayward to talk about walleye and muskie management while celebrating the Northwest Wisconsin Lakes Conference, one of the state’s premier lake education events.

The annual NWLC represents the counties of Douglas, Bayfield, Washburn, Sawyer, and Burnett counties – and the 3,361 lakes within their boundaries – and offers interested citizens information on lake-related topics.

John Gozdzialski, the DNR’s Northern Region director, headlined this year’s agenda.  The 35-year DNR veteran began his career as a field biologist. He spoke about the people, their passion, and partnerships. 

“ ‘Up north’ is a state of mind,” Gozdzialski said. “Surveys have shown 90 percent of the public is concerned about what’s happening to the north. We’ve seen cabins fall and mansions rise on our lakes beginning years ago, which is why we began the Northern Initiatives where the motto was ‘Keeping the North the North’ in 1996.”

Gozdzialski, after showing slides of lakeshore development changes since 1960, urged attendees to support local units of government that support lakes, saying, “Development and lake protection can continue to work together.”

During a question-and-answer session, one attendee asked Gozdzialski about the proposed changes to lake-protection laws.

“There are zoning proposals in the (current) budget proposed that will affect the future of the lakes. What is the DNR going to do about talking to legislators about what to do about this?” the attendee asked. 

“The DNR is not in the lobby business, but must implement what’s in the budget. You folks need to have your voices heard and you can do that by reaching out to your legislators,” Gozdzialski said.

Another question fielded by Gozdzialski referenced a reduction in positions in the DNR’s Science Bureau that were part of the budget.

“We currently have 60 researcher positions and 20 will be gone with this proposal. If it’s the will of the legislators, we will have to implement whatever comes out of it,” he said. 

Jeff Kampa, of the Spooner office, worked in the DNR’s Bureau of Science Services for years until the current disruption of the program. The bureau consists of “researchers, analysts, and other critical thinkers who provide the expertise and foundation of all science-based decision making of the DNR,” according to the DNR website. Kampa now works in the DNR’s Bureau of Fisheries Management. While in research, he specialized in muskies. His presentation dealt with the muskie’s life history and key habitat requirements.

“Our goal for muskie management is to maintain habitat so the population is self-sustaining,” Kampa said.

He said muskies spawn later than most other game fish, when the water temperature is between 49 and 60 degrees in depths less than 10 feet.

“They seem to prefer bulrushes to spawn in and it takes 8 to 14 days for the eggs to hatch. We’ll supplement lakes with stocked fish if needed and then determine if the stocking is contributing to the population,” Kampa said.

Kampa used Sawyer County’s Sand Lake as an example of where studies have been conducted to monitor muskie growth and survival.

“Sand Lake muskies were 31.4 inches long at age 6, although when they reach maturation they add body depth. The energy doesn’t go into body growth,” he said.

Female muskies are bigger, as a rule, since males grow slowly as they mature. One example Kampa used was of a male caught in 2013 and 2014 that remained at 36.5 inches. When asked what the biggest muskie he’s ever handled was and where he thinks the biggest muskie in Wisconsin is, his answers were a mid-50-inch fish (from northwestern Wisconsin). “The state’s biggest muskie is probably in Green Bay,” he said.

Gretchen Hansen is a DNR fisheries research scientist. Her research examines how food web interactions and environmental drivers shape aquatic communities, with a more recent focus on walleyes. 

On many inland lakes, walleyes are failing to regenerate their numbers, which scientists call recruitment failure.

“Walleye recruitment has been declining since the early 1990s, about 6.6 percent on average. Adult walleye density is declining also, but not as much as juveniles,” Hansen said. 

Largemouth bass numbers, on the other hand, have been rising in some lakes.

“The density is increasing about 4 percent per year, and there has been a gradual change to more liberal rules concerning them,” Hansen said. “There has been a lot of speculation as to whether largemouth bass are impacting walleye numbers, but there are many factors that may have contributed to this change in bass and walleye populations. Water temperature, shoreline development, and stocking are some of them.

“I want to emphasize the idea that correlation (decrease in walleyes and increase in bass) does not mean causation. Many, many things have changed over the past several decades, so pulling apart cause and effect is difficult. So far, direct predation by bass on walleyes does not appear to explain the walleye decline,” Hansen said.

Although walleye numbers appear to be declining across Wisconsin, Hansen said there are exceptions.

“Lake-specific trends in walleye recruitment are variable. Most lakes where we have enough data to look for a trend show declining recruitment, but in some places recruitment is holding steady or even increasing. Understanding the differences between these lakes is important,” she said.

Hansen also shed some light on a popular theory among many state residents. “When people hear about walleye declines, they immediately ask whether tribal spearing is the cause. In fact, both adult walleye density and walleye recruitment are higher in lakes that have been speared than lakes that have never been speared. Perhaps more importantly, the frequency with which a lake has been speared since 1990 is not at all related to the lakes-specific trend in walleye. Lakes that are speared every year show a mix of walleye declines and walleye increases, and walleyes are declining in lakes that have never been speared. Therefore, something else besides spearing must be responsible for these declines,” she said.

The jury is still out on why Wisconsin walleye numbers on inland lakes are declining, but it’s a trend seen throughout the Upper Midwest and, to some extent, Canada. Some still think adult largemouth bass are a factor, although researchers from UW-Stevens Point pumped the bellies of bass in one study and found no walleyes in those fish. Another suspicious factor is climate change, but there is no obvious correlation, although while it has affected all lakes, walleye numbers haven’t declined in all of them. What has been documented is that walleyes do better in cooler water and bass find warmer water more suitable.

Those attending the conference gave it good reviews. The question now is, with the reduced number of research scientists in the DNR, who will make these determinations so fisheries managers can develop strategies to address them?

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