There are plenty of fish to catch in area lakes. There will continue to be fish to catch in the future, but there is also concern about the one species that people seem to want to catch the most that is now showing up in recent DNR surveys.
That message was delivered by Dean Beck of the Glenwood Area DNR on Aug. 26. Beck has worked in fisheries management for more than 30 years and serves as the Glenwood Area Supervisor. His work area emcompasses Douglas, Grant, Pope and Stevens Counties.
Beck spoke at a public meeting for a crowd at the Legacy of the Lakes Museum in Alexandria where he broke down the history of fisheries management in Minnesota before looking at the current state of area lakes and what fishing might look like into the future.
“We still have pretty darn good fishing,” Beck said near the end of the presentation. “We will continue to have good fishing, but we need to slow that aging process (of the lakes).”
Beck stated that bass, sunfish and northern pike populations have been increasing, though the average size of game fish, specifically pike and bluegills, has declined. Walleye numbers have been stable until recently. That’s where his concern lies.
Beck provided data from surveys conducted by the DNR this summer on two popular fisheries in the area -- Lake Ida and Lake Miltona. Walleye catch rates were down considerably on both lakes from the last gill-net surveys done in 2015, from 14.3 to 5.3 on Miltona and from 10.1 to 3.4 on Ida.
Beck noted a handful of possible explanations for the lower catches. Clearer water caused by zebra mussels could mean walleyes are moving deeper and less vulnerable to capture. Nets might be more visible to the fish, which helps them avoid them.
Beck admitted it could be random chance. The possibility also exists that the lakes now have a diminished carrying capacity, the amount of fish a system can support based on habitat and food available, or that there is reduced survival and recruitment of young walleyes.
Where are the young walleyes?
The latter of those possibilities has shown up in the data recently.
The DNR has conducted electrofishing catches of young-of-the-year walleyes, those less than a year old, on Ida and Miltona. Beck’s numbers dated back to 2000.
Miltona had a high catch rate of 124.7 in 2009 and as high as 111.9 in 2011. Ida’s high catch rate was 125 in 2001. It was 21.9 in 2013, but since 2016 not a single young-of-the-year walleye has been caught in this survey on either lake.
“It was certainly very interesting and well organized,” Douglas County Lakes Association president Steve Henry said of Beck’s presentation. “The biggest impact and kind of the worrisome part was when he talked about the walleyes in Lake Miltona and Ida particularly, but probably in all of our lakes. The numbers they’re seeing is really pretty worrisome.”
Zebra mussels to blame?
Henry, who is also an active member of the Viking Sportsmen in Alexandria that has helped stock walleyes in area waters, believes that zebra mussels are the likely cause of the reduced numbers the DNR is starting to see in the surveys.
Zebra mussels were found in both Ida and Miltona earlier this decade and many Douglas County waters are now infested. Zebra mussels feed on plankton at a rapid pace, taking the nutrients from the lower levels of the water's food chain that other species rely on. One zebra mussel can filter one quart of water per day.
Zebra mussels were found on Lake Carlos on the Alexandria Chain of Lakes in 2009. Carlos has been part of a collaborative effort between the DNR and the Minnesota Pollution Control Agency called the Sentinel Lakes Program. The program looks at every aspect of a lake’s health on different bodies of water across the state.
“It gave us a unique window into the impacts of zebra mussels," Casey Schoenebeck, a Sentinel Lakes coordinator with the DNR, said in an interview with the Echo Press in 2018.
One area that the program tracks is the zooplankton densities. Zooplankton consists of animals at their most immature stages. Their levels have dropped considerably on Lake Carlos since 2008, down to their lowest levels ever during the 10 years of the study in 2018.
“They’re eating that phytoplankton, therefore the minnows, the little creatures don't have any food supply so the small fish don’t have anything to feed on,” Henry said. “It's a vicious cycle. I think it’s something we’re not going to solve real quickly, but I’m excited about this mapping the genome of the zebra mussels. They are looking at using the technology they used to strengthen oyster shells to turn it around and soften zebra mussel shells so the sunfish and other fish can eat them.”
Research such as that continues to be done as scientists look for ways to combat zebra mussels as they spread across parts of Minnesota. Other effects of the mussels filtering lakes are clearer waters and expanded weed growth as sunlight reaches deeper depths.
“There are certain fish species that are going to prosper in that,” Beck said. “We’re seeing that.”
Fish like bass, northern pike and panfish can thrive in those types of environments, but every lake has a certain carrying capacity overall, Beck said.
When pike numbers are high, walleye numbers tend to be lower. Fish such as northerns, walleyes and bass compete for many of the same prey. The yellow perch is a primary bait species, and Beck said their surveys show low perch numbers across the area and the state.
What the future might hold
Henry has fished around Alexandria for many years himself. He is not on the water as much now in retirement, but he knows plenty of anglers who had a pretty good open-water season.
Bass fishing continues to be spectacular in many ways. Walleye fishing often slows down by August, but it was quite good earlier this summer, Henry said.
Like Beck, he is optimistic about the future of fishing in the area for certain species, but there are concerns as it pertains to what will happen to walleye angling if a similar path continues.
“I think it is going to change. I think probably walleye fishing, you’ll maybe be able to have a few lakes, but I just don't think it’s going to be near what we’ve had,” Henry said. “We’ll still have northern pike, we’ll certainly have bass, crappie and sunfish.
“It’s multifactorial. We’ve overdeveloped the lakes, other pollutions, having green grass right to the shoreline and not wanting to have a weed in it so we fertilize it and we spray it and all that stuff washes in the lakes. We’re really putting a lot of stress on our lakes. I’m hoping that with enough education we can change habits.”