Nearly 20 Beltrami County lakes infested with invasive species pose environmental problems – Bemidji Pioneer

BEMIDJI – There are 19 bodies of water in Beltrami County infested with three aquatic invasive species, which have likely bred in the millions.

Since 2014, zebra mussels and snail snails, as well as the starry stonewort plant, have been found throughout the county. The latest discovery, announced by the Minnesota Department of Natural Resources on Friday, June 25, was a Starstone found in Lake Pimushe.

The full list of infested water bodies in the county is as follows:

  • Lake Andrusia, infested with zebra mussels since 2014.
  • Beltrami Lake, infested with starstone since 2019.
  • Lac Bemidji, infested with zebra mussels since 2018.
  • Big Rice Lake, infested with zebra mussels since 2014.
  • Blackduck Lake, infested with tap snails since 2018.
  • Cass Lake, infested with zebra mussels since 2014 and starstone since 2016.
  • Carr Lake, infested with zebra mussels since 2018.
  • Lake Irving, infested with zebra mussels since 2018.
  • Kitchi Lake, infested with zebra mussels since 2014.
  • Little Rice Lake, infested with zebra mussels since 2014.
  • Lac Marquette, infested with zebra mussels since 2018.
  • The Mississippi River, infested with zebra mussels since 2018.
  • Moose Lake, infested with starstone since 2016.
  • Pimushe Lake, infested with zebra mussels since 2019 and starry stonewort in 2021.
  • Pug Hole Lake, infested with zebra mussels since 2014.
  • Upper Red Lake, infested with starry stonewort since 2016 and zebra mussels since 2018.
  • Turtle Lake, infested with starry stonewort since 2016.
  • Wolf Lake, infested with zebra mussels since 2014 and starry stonewort since 2018.
  • A creek connecting Big Rice, Cass, Kitchi, Little Rice and Pug Hole lakes, which have been infested with zebra mussels since 2014.

Starry Stonewort starts growing around mid-June and can grow up to 6 inches to a foot below a lake’s water surface. (Annalize Braught / Bemidji Pioneer)

A lake determined to be infested begins with the county. Beltrami County Aquatic Invasive Species Lake Technician Bruce Anspach said when an infestation is discovered, a report should be sent to the DNR.

The DNR will then send an official to visit the site with Anspach for confirmation before listing it as an infested body of water.

RELATED: Search for Starry Stonewort: County continues to monitor invasive algae found in five lakes

“We have started in-water searches for invasive species as part of our early detection program,” Anspach said. “When we come out with the DNR, we’ll see if it’s widespread or small. That’s our goal with early detection, so maybe we can do something about that.”

Of the three, MNR aquatic invasive species specialist Nicole Kovar said zebra mussels are the most damaging. The mussels, which measure no more than two inches, consume by attracting anything nearby.

“He goes through what he wants and spits out what he doesn’t want,” Kovar said. “Most of the time what he spits out is what nothing else will eat either, which increases the toxicity around him. By eating all the plankton in their area which are larvae including our native fish and clams need to survive, it also takes in the lower part of the food web.”


Zebra mussels encrust clam shells in Cass Lake in 2016. (File photo from Forum News Service)

According to Kovar, an adult female mussel can lay up to a million eggs per summer. Early in their life, mussels are microscopic for nearly three weeks while the shells are forming.

“Not all of them survive, but even if 100,000 out of that million survive, it causes a very steep growth curve,” Kovar said. “It’s the most detrimental species in the United States for its effect on the ecosystem. But now with the ecosystem there can be economic impacts because they can also clog water supply lines. They prefer shaded areas, so they can colonize these pipes.

“It makes a difference in bait harvesting and water usage for everything in your home,” Anspach said. “Let’s say a person pumps water from a lake to water his garden. If she’s by a lake, she can do that, but she also has to do something about her water usage. On Lake Bemidji, with water intake pipes, we are already seeing them starting to get clogged with zebra mussels.”

Kovar said there was no way to eliminate the molds and instead people had to adapt to their current presence.

Other species infesting some of the county’s waters are the hard-to-find snail snails.

“Unless you know what you’re looking for, it can be hard to tell they’re snails,” Kovar said. “They breed a lot and they compete with our native species for the same resources.”

The most widespread ecological problem with snails, however, is how they act as hosts for parasites.

“These parasites can cause waterfowl stomach hemorrhages and death,” Kovar said. “Thousands of deaths are attributed to them and our native snails do not harbor these parasites.”

The other species of concern, star stonewort, is a micro-algae. Each strand of algae is its own individual cell, and the species is known for these pieces to stick together, forming chains and mats.


Signs near the Nymore water access alert boaters to invasive species in the lake and remind them to help stop their spread. (Jillian Gandsey / Bemidji Pioneer)

A critical issue with algae was how natural resource officials were to learn about the plant on the fly.

“We don’t know much about the Starstone because it hasn’t been well studied before,” Kovar said. “When we were looking at how to handle it before and stop it, only one article even referred to it. More research is being done on its phenology, reproductive ability and how long it can survive out of water.”

What is known is that it can reach 10 feet in the water and have negative effects on recreation and ecology.

“It has a recreational impact because it can get tangled up and then come to the surface,” Kovar said. “In a lake, it makes boating difficult. Even if you manage to cross it with a boat, you also cause more spread, because you can cut off a section and those viable cells can still take root.”

Environmental impacts, meanwhile, concern other native species.

“In Beltrami County, we have more lakes than any other in Minnesota and we monitor its behavior from lake to lake,” Kovar said. “When we find it, it is quite abundant and grows very quickly. We are concerned that it will compete with native plants and loss of diversity with native species.”

The most noticeable way it affects native vegetation is how its growth can shade out other plants, which need the sun to germinate.

In ongoing prevention efforts, Anspach said his office’s biggest concern is boaters traveling from one body of water to another within five days.


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“It is suggested that you dry your craft for five days or have it decontaminated,” Anspach said. “Last year we had 23.8% of our boaters going to a different body of water within five days. If they go to Lake Bemidji and then come back to that lake, that doesn’t count, it is only if they go to a different one.”

To help in that effort, Anspach said after a boater empties their craft, they should also empty their livewell and bait.

“Sometimes not all the water is drained out when the plug is removed,” Anspach said. “We focus on this behavior and it’s easy to fix. Even if you can’t find any plants or animals, it’s easy to throw hot water into your tank because you’re dealing with very small mussels. or plants.”

For already infested water bodies, Kovar said the DNR effort is a mix of continued research into management methods and educating the public about more prevention. As part of this latest work, Kovar said the agency is working across state lines and with Canadian authorities to prevent the species from entering Minnesota from outside water sources.

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