DNR addresses declining walleye population in Crescent Lake

Last week, the Department of Natural Resources (DNR) held an informational session regarding the declining walleye population in Crescent Lake near Rhinelander. The session included an announcement that the agency is considering adding Crescent to its list of “lakes of concern.”

James Yach, DNR Secretary’s director for Northern Wisconsin, stated that the department was looking for information from stakeholders regarding the walleye issue. Management options and partner engagement would be the next steps, he explained.

According to DNR treaty fisheries supervisor John Kubisiak, the Walleye Lakes of Concern project was developed as a result of concerns about walleye recruitment in some lakes across the northern region. Since the early 2000s, recruitment has been slowly declining, he noted.

Walleye are cool water species. As the climate warms, and with predictions of continued warming, coupled with the fact that Wisconsin is already at the southern end of walleye range, populations here will continue to struggle, he explained.

 Warm water species such as bass will continue to thrive under that same scenario. he added. When one species is harmed another is benefited, he explained.

“When we start talking about rehabilitating these walleye populations that are struggling, we need to realize that we can’t fix maybe everything or every single spot,” he said. “We need to prioritize.” 

He also stressed that it’s important to manage expectations and realize that things may not remain the same across all of the walleye range. There are still “bright spot” lakes where walleyes continue to do well, he added.

The Lakes of Concern process is a collaborative effort. It is driven by stakeholder engagement with clear objectives. Those objectives then inform management decisions. The process also involves routine monitoring and regular reporting. 

Other projects

Kubisiak spoke about three recent rehabilitation projects. One of those was on the Minocqua Chain. Young of the year numbers in the Chain started to drop off in the early 2000s and there was significant concern regarding poor recruitment numbers. That concern was such that, by 2011, rule changes went into effect, which included removal of the bass size limit. 

In 2012, changes were made to stocking efforts. Large fingerlings, measuring 6 to 8 inches, were stocked in September. These larger fingerlings have a higher survival rate than their smaller counterparts, although they are costlier to produce.

In 2014-2015, a partner group was created to study the recruitment issue  in the Minocqua Chain, Kubisiak continued. In 2024, he said, the Chain was reopened to restricted harvest. He did not mention that the restricted harvest for tribal anglers took place one year earlier than planned, and was a result of a tribal harvest that took place this spring. The early opening took place under the same regulation under which the Chain was to open next year, a one-fish limit with a minimum length of 18 inches and a protected slot between 22 and 28 inches.

He said the goal for that rehabilitation was to have three adult fish per acre and to have multiple year classes present and a system that would support natural reproduction.

Kubisiak then spoke about Lac Vieux Desert (LVD) and the recruitment failures found there starting in 2006. This was another lake where walleye recruitment went from good to mediocre and then dropped to near zero. In 2013 LVD voluntarily suspended harvest. The Mole Lake Tribe followed suit shortly after. 

By 2017, Kubisiak said, a plan was put in place to rehabilitate LVD. That plan had a goal of 2.5 adult walleye per acre. The plan also had a goal of restoring natural reproduction in that lake. 

When the same problem was found on Lac du Flambeau lakes, where recruitment was found to be falling in four lakes from 2012-14, Kubisiak said they got onto the problem faster, having seen it before. In 2018, annual meetings started with Lac du Flambeau, the Great Lakes Indian Fish and Wildlife Commission (GLIFWC) and the DNR. This, Kubisiak said, was where the term Walleyes Lakes of Concern originated.

By 2020 the partners started working on a plan. That plan was finalized in 2022, and became the prototype for the idea behind the Crescent Lake meeting, Kubisiak said. 

In these three projects he said, the large fingerling stocking is working well and there are more fish per acre, but still recruitment is not where it needs to be, so the goal has not been achieved yet.

Crescent Lake specifics

DNR Oneida County fisheries biologist Nathan Leaderman addressed the issues specific to Crescent Lake. He described it as a 616-acre lake with cool, clear water. There are a wide variety of fish in the lake and are all interacting within the lake, he added.

The current walleye regulation on Crescent Lake is set up for a slow-growing, well-reproducing system with no minimum but only one fish over 14 inches with a three-bag limit, he added.

Muskies are being stocked and starting in 2021, small fingerling walleyes have also been stocked. In 2023, a change was made to large fingerlings.

In Crescent Lake, walleye populations have fluctuated through time. However, in 2022, those populations fell to the lowest ever, at 2.9 per acre. Right now, Leaderman said, there are approximately three adult fish per acre. While the situation is not dire, there is concern over lack of reproduction and of age-0 walleyes. Somewhere from 2017 to 2018, natural reproduction stopped occurring, he reported. While there had been years in the past with little to no production of age-0 fish, there have never been so many of those years in a row, he added.

 There are various ways the problem can be addressed, he said. With that amount of pressure the fishery receives from hook and line anglers as well as tribal members, he said it was important to consider options.

Mike Meuhring from GLIWC spoke about how GLIFWC has been involved in walleye restoration and the ins and outs of tribal harvest. One of the main purposes of GLIFWC, he said, is to help tribes exercise their treaty rights and to help protect those resources in the longer term. Tribes, Meuhring said, look at resources in a much longer term than he did when he first came to the area. Tribes, he said, think about the seventh generation, and believe those are the people for whom they should be looking out. 

GLIFWC, too, has seen the decline in walleye fisheries in lakes such as Crescent. He said the commission has an interest in collaborating with others, as they have in the past in many projects.

Meuhring also explained how the tribal harvest is monitored. Tribal harvest is regulated by a safe harvest level and a quota system for each lake. Walleye population estimates are done in the spring every year. The total allowable catch is the number of fish that could be caught out of a population without negatively affecting walleye numbers. In the 1990s, the number agreed to was approximately 35%. For instance, if a walleye population was estimated to be 10,000, safe harvest would be 3,500 fish. The quota for tribal harvest from the lake is then set as a percentage of the allowable catch. The safe harvest is sent out to tribes, which then declare their quota for each lake, which is usually 10% of safe harvest or less for each lake. Each lake is then opened on a nightly basis.

 In the case of Crescent Lake, that number is somewhere around 200 fish. The tribe then issues permits for tribal harvest and creel surveys are completed at the landing at the end of the night(s) on which tribal harvesting takes place. Between 1999 and 2023, almost all of the fish caught have been sexed and measured on Crescent Lake, and average tribal harvest has been 204 walleyes per year. In 2024, even though the original tribal quota stayed at around 200 fish, the tribe decided to reduce its take to 90 in recognition of the decline in population.

The average length of fish that are speared, he said, is 14.5 inches. Males are more vulnerable to spearing as they are up in the shallows for a much longer time than female fish, he added.

Citizen concerns

At that point, the meeting was opened to questions and observations from others in the room. 

There was significant discussion about the increase in bass populations in Crescent Lake, especially in the last 10-15 years. Some were concerned that the lake would turn into a “bass factory,” and that there is a continued interest in catching walleyes out of the lake as well.

Some residents were concerned about invasive species in the lake as well as the fish populations in the lake. One resident had divided into five-year increments the number of fish that were speared in the lake on average for those periods from 1990 which, in his mind, would make it more digestible. 

In the first 15 years 2,335 walleyes were taken from tribal harvest, he said. In the most recent 15 years, that number was 3,820 fish. Over the years, he said this showed the number of walleyes taken from the lake at the same time the population had been decreasing. 

DNR fisheries supervisor Royce Zehr said the walleye population decrease was not noticed until 2018. Leaderman noted it was at its lowest ever in 2022, but its population had always remained at what he called a “functional” level.

There was also a concern expressed by some lake residents that the DNR had not allowed them to fight the invasive species issue. In their estimation, the situation is partially the result of the department denying their chemical treatment permit applications. More native plant growth would provide a better habitat for walleyes, they asserted.

Others suggested the walleye decline is the result of an increase in spearing pressure. The lake district was spending money to create an aquatic plant management plan and had asked for tribal input so everyone involved could be on the same page. There was some anger over the fact that the district had applied for a permit, which was originally approved, but then they were told their permit would not be approved, which they felt was due to the tribes not agreeing to the plan.

“I want to make a point of clarity here,” Leaderman said. “Yes, there were parts of the aquatic plant management plan that were not approved due to concerns of the walleye recruitment issue.” 

Looking at the graphs showing the decline in walleye recruitment, the department’s intent is to look for causal factors of that decline, one of which may be the affects of ProcellaCor treatments on the lake, he explained.

 He said it had nothing to do with tribal harvest, but was only concerned with walleye recruitment. Zehr shut down further comment from those intent on discussing that point further and asked that the discussion move on as others had concerns to share.

The discussion turned to the timing of tribal spearing. Kubisiak stated that no matter when fish were taken during the year, whether through tribal spearing, open water anglings, or through the ice, those fish would still not be available to spawn the next year. The point, he said, would be to control mortality, no matter what time of the year it might take place. 

That said, there was little concern about when tribal harvest occurred, as there was a quota for that activity. When it came to hook and line anglers, Kubisiak said, the state could not issue walleye tags, for example. 

The management options are season length, fish length and bag limits. Yet, when asked why sturgeon were protected during spawning, yet walleye were not, he responded that the hook and line season was not open at that time for that reason, and that there were firm quotas for tribal take.

The conversation then turned to what might be happening that is causing these declines. It was explained that the DNR office of applied science had taken up a study on Escanaba Lake to look into some of those issues.

To date, the findings have shown that habitat is likely the main driver and the fact that things in some lakes are changing in ways that favor warm water species of fish.

Kubisiak said walleye declines are being seen in places across this part of their range and that this is a broad-based phenomenon. For that reason, the thought is that climate change is the underlying issue. While water temperature may or may not be the direct driver, there may be more weed growth and other conditions precipitated by these changes that simply favor warm water species. 

There is also ongoing research at UW-Stevens Point focused on what some of those drivers might be, where recruitment bottlenecks are occurring and why fry are not making it past June or July.

Development, too, is a big issue for walleyes, which Meuhring referred to as “wilderness fish.” Human populations are a stressor for walleye populations. With habitat likely being a big driver of walleye populations, changes in habitat that come with development around a lake could also be having an impact — with all of the factors being a piece of the puzzle in each lake.

“To be completely open and honest about this, sometimes harvest can be too high on these systems,” he said. “While it is not necessarily one group or another, and it can vary by lake, but when harvest is all added together, and recruitment falls off, declines should be less of a surprise than it has been.”

Looking forward

Leaderman said there are some tools available to address the concerns about Crescent Lake. Those would include stocking, harvest changes and habitat protection and enhancements. Stocking will continue as well as spring monitoring.

The key is to set up specific and measurable objectives and to take specific management actions. Partners in the effort will include DNR, the Mole Lake Band, GLIFWC, the lake association and district as well as other stakeholders.

The recommendation the department is currently looking at, should the lake be formally named a Walleye Lake of Concern, would involve a restrictive walleye harvest, much like the Minocqua Chain, and a liberalized bass take with no size limit on bass. 

This would be a big swing, as the current regulation on bass on the lake is one fish over 18 inches, as it has been managed under the trophy bass fishery regulation for a number of years. 

However, the changes would not be put into place until 2027, as rule making through the department process takes 30 months after the scope statement comes to the Natural Resources Board.

There would also be several opportunities throughout the process for continued public input. 

Beckie Gaskill may be reached via email at [email protected].