ALEXANDRIA, Minn. — Those who own lake property may sometimes wonder if an infestation of aquatic invasive species harms their property values.

Researchers at the Minnesota Aquatic Invasive Species Research Center in St. Paul wonder also, and are examining hundreds of thousands of property transactions in Minnesota to determine the answer.

One interesting phenomenon they observed was that properties along lakes infested with Eurasian watermilfoil actually have property values that are higher than lakes without that particular invasive species.

“It was surprising to us,” said Shyam Thomas, a researcher at the Research Center who is part of the team studying the link between property values and aquatic invasive species. He presented the study at the center’s Research and Management Showcase that started Tuesday, Sept. 22.

He stressed that the research remains ongoing, and that one explanation for the higher values may be that the lakes with Eurasian watermilfoil are highly sought after for recreational reasons, and that popularity keeps prices high. Lakes that see more traffic are more vulnerable to invasive species like Eurasian watermilfoil.

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Researchers aren’t yet able to determine the economic impact of invasives. Several smaller studies have found Eurasian watermilfoil could drive property values down as much as 19%.

Jim Kutzner, president of the Clearwater County Lake Property Owners, said during a session to discuss the study that he wonders if property values remain high because buyers don’t pay much attention to them.

“Maybe people don’t recognize AIS … as being very important,” he said.

Aquatic invasive species create major headaches for lakeshore groups, who often have to pay to control them. Some lakeshore groups complained during the session that lake users don’t seem to care about protecting lakes, and one said that only 30% owners on their lake belong to their association.

“Seventy percent of the people don’t care enough to participate or even pay attention,” said Jim Bartelme, president of the Stearns County Coalition of Lake Associations.

Researchers looking at the link between property values include members who study invasive species as well as economists. It will take further analysis before researchers are able to draw any conclusions from the data they have gathered.

The study’s chief goals are trying to understand what makes lakes more susceptible to Eurasian watermilfoil, what causes some infested lakes to have more of the infested plant than other lakes, and what role climate change plays in causing it to proliferate.

MnDNR/FOCUS
Even a small piece of Eurasian watermilfoil is enough to start a new plant in a previously uninfected lake.
MnDNR/FOCUS Even a small piece of Eurasian watermilfoil is enough to start a new plant in a previously uninfected lake.

In Douglas County, Lakes Carlos, Indian, Le Homme Dieu, Oscar, Round and Victoria are all infested with Eurasian watermilfoil, according to the DNR.

Also presented on Tuesday was research into non-native carp and zebra mussels.

Carp

Researcher Przemyslaw Bajer presented before-and-after aerial shots of a Minnesota lake that had been infested with invasive carp. The before shot showed a green, algae-covered surface. After the carp were removed, the aerial shot showed clear water.

That illustrates the problem with invasive carp, which nose around the lake bottom and release contaminants into the water.

Bajer’s team has been working on ways to get rid of them, which could come in handy when it comes to waters like Alexandria's Lake Winona.

One effort has been to try to herd fish by baiting them with corn and other grains during the summer. Radio transmitters allow them to track certain carp, and they’ve found that they can be trained to show up at bait piles, which could make them easy to catch. The problem? They show up at different times and don't stick around long. The next step: Train them to arrive at a particular time.

Another possible tactic is to herd them, cattle style, into a pen. Researchers strung an electric barrier across a river when the carp were swimming upstream to spawn in the spring. The fish veered away from the barrier and into a trap, where they were killed and removed.

This project, which included a conveyor belt and which Bajer said cost about $100,000, wasn’t able to be fully tested because of the pandemic. However, it shows promise, he said.

Zebra mussels

It takes a long time to track a zebra mussel infestation using current methods, either divers or underwater cameras, said researcher Jessica Kozarek.

That makes it difficult to know how the mussel population changes over time and how effective treatments are.

Kozarek is working on a way to map zebra mussels in a water body quickly, using sonar.

Sonar can map sand, rock or gravel, and can also map the location of mussels, which have a different density, she said.

When developed, this tool can allow lake associations or other monitors to track the effectiveness of treatments and also how populations change over time.

In Douglas County, dozens of lakes or water bodies have become infested with zebra mussels over the past decade, according to the DNR.