Facing Invasive Species, Lake Groups Struggle With Decisions About Chemical Treatment
During the first week of June, a boat sprayed chemicals into the waters of Anvil Lake in Vilas County for the first time.
It was applying an herbicide called 2,4D, targeting Eurasian watermilfoil, an aquatic invasive species whose presence in the lake has grown and grown.
The decision to use chemicals in treating the problem was difficult and often controversial for lake leaders.
But it’s a decision more and more lake groups in the Northwoods are forced to consider as invasive species spread.
In many ways, Anvil Lake is where Dr. Amy Kuhns grew up.
“I learned how to swim, how to fish, how to waterski all on Anvil Lake,” she said.
Kuhns is now a physician and President of the Anvil Lake Association. She calls the 377-acre lake “the jewel of the Northwoods.”
But in 2012, it started becoming a little less pristine when Eurasian watermilfoil showed up and started expanding in acreage.
“[It became] very difficult to swim or fish or boat in a significant area of our lake,” Kuhns said.
Invasive species infestations have hit lakes across the Northwoods, and Anvil Lake responded by sending divers to hand-pull the weeds.
Soon after, it bought its own Diver Assisted Suction Harvest (DASH) unit, a boat that works with divers to clear the plants. That quickly became a major operation.
“It literally is like running a small business, hiring the personnel, making sure we have a properly functioning DASH unit,” Kuhns said.
In each of the last three years, workers removed 20,000 pounds of milfoil from the lake.
Gene Welhoefer, a lake association member, was one of those divers. He described the hundreds of hours he’s spent in a SCUBA suit, pulling milfoil from Anvil Lake.
“I did it because I love the lake and I think that it was a good management technique,” he said. “I would have loved it if I could have pulled every single plant out of the lake that was going to be the invasive, but that’s not a reality.”
Gene and his wife Donna have had lake property since 2006.
But despite tireless work, the milfoil cover was relentless, said Kuhns, the lake association president. Hand-pulling and the DASH boat weren’t enough, she said.
“It’s been very frustrating to see this effort fail," Kuhns said. “It’s not for a lack of trying or lack of funding. This is just our reality.”
Last fall, the Anvil Lake Association took a survey of interested parties.
Should it take an even more aggressive step and start chemical treatment?
Fifty-nine percent said yes and 23 percent said no, with 18 percent undecided.
Kuhns, a physician, wanted to know about the health and safety of putting the chemical 2,4D in the lake. She and the board set up informational meetings and reviewed study after study.
Kuhns left convinced.
“All of the research that I’ve been analyzing, I’ve become comfortable myself that this herbicide treatment could be conducted in a safe way for public health,” she said.
In her interpretation of the data, the lake will remain “absolutely safe” for human use, including swimming, boating, and fish consumption.
That’s where Gene Welhoefer’s path diverged.
Also a lake association board member, he voted against chemical treatment, fearing too many unknowns about human health.
After the board supported the move, he resigned.
Soon after, he saw an herbicide sprayer hit the lake.
“It kind of ruined my morning. My plan was to go catch a few fish, drink a nice cup of coffee on the lake, watch the sun come up. It made me sick to my stomach almost,” he said.
Welhoefer argues there’s not enough evidence showing 2,4D is safe and poses no risk to human health now or in the future.
“You can’t take your footprint back. With decisions that were made, we made a footprint, and it’s going to lead us down a path,” he said. “We don’t want to be the guinea pig. We don’t want our neighbors to be the guinea pigs. I don’t want to drink this.”
DNR Invasive Species Specialist Carol Warden, who works out of the UW-Madison Trout Lake Station in
Boulder Junction, agrees there’s more to know about the chemical, its effectiveness, and its impacts on the lake around it.
“Some of those studies are eye-opening on how we’re being judicious about using this form of control,” Warden said.
She’s seen debates over chemical treatment get tense, like at Anvil Lake, but views them as an opportunity to learn, educate, and discuss.
“All of those things are super challenging, but that is so important,” Warden said. “It’s the best kind of challenge.”
Thirteen years ago, people on the Eagle River Chain of Lakes had the same debate about its own abundant milfoil.
Almost 280 acres of milfoil were in the water in 2007.
The next year, the Unified Lower Eagle River Chain of Lakes Commission started using chemical treatment.
By 2019, the acreage had shrunk to just four percent of its original extent. The group no longer uses chemicals.
“It’s a huge success,” said Carole Linn, a commission member.
Linn sees what was done on her chain as a statewide model for EWM management and reduction.
She said studies have shown there has been no negative effect on native plants, either.
On Anvil Lake, Welhoefer hopes the chemical treatment goes well, even though he’s opposed to it.
“I hope I’m wrong. I would love it if in 30 years people could say, ‘This is safe. This is the best thing we’ve ever done for the lake,’” he said.
But Welhoefer feels he can’t say that just yet.