BEMIDJI, Minn. -- There are 19 bodies of water in Beltrami County infested with three aquatic invasive species, which have likely reproduced in the millions.
Since 2014, zebra mussels and faucet snails, as well as the plant starry stonewort, have been found across the county. The latest discovery, announced by the Minnesota Department of Natural Resources on June 25, was starry stonewort being found in Lake Pimushe.
The complete list of water bodies with infestations in the county are:
- Andrusia Lake, infested with zebra mussels since 2014.
- Lake Beltrami, infested with starry stonewort since 2019.
- Lake Bemidji, infested with zebra mussels since 2018.
- Big Rice Lake, infested with zebra mussels since 2014.
- Blackduck Lake, infested with faucet snails since 2018.
- Cass Lake, infested with zebra mussels since 2014 and starry stonewort 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.
- Lake Marquette, infested with zebra mussels since 2018.
- The Mississippi River, infested with zebra mussels since 2018.
- Moose Lake, infested with starry stonewort since 2016.
- Lake Pimushe, 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 stream connecting Big Rice, Cass, Kitchi, Little Rice and Pug Hole Lakes, infested with zebra mussels since 2014.
A lake being determined as infested starts with the county. Bruce Anspach, Beltrami County aquatic invasive species lake technician, said when an infestation is found, a report has to 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 water body.
"We've started some in-water searches for invasive species as part of our early detection program," Anspach said. "When we go out with the DNR we'll see if it's widespread or small. That's our goal with early detection, so we might be able to do something about it."
Of the three, DNR aquatic invasive species specialist Nicole Kovar said zebra mussels are the most detrimental. The mussels, which grow to no more than two inches in size, consume by drawing up everything nearby.
"It goes through what it wants and spits out what it doesn't," Kovar said. "A lot of the time, what it spits out is what nothing else will eat either, increasing the toxicity around itself. By eating all of the plankton in their area that are larval that our native fish and clams need to survive, it's also taking out the lower portion of the food web."
According to Kovar, an adult female mussel can put up to one million eggs out per summer. Early on in their life, the mussels are microscopic for nearly three weeks while the shells are built.
"Not all of them survive, but even if 100,000 survive out of that million, it causes a very steep growth curve," Kovar said. "It's the most detrimental species across the United States for its ecosystem effect. But now, along with the ecosystem, there can be economic impacts, as they can also clog water supply pipes. They prefer shady areas, so they can colonize in those pipes."
"It makes a difference in bait harvesting and using water for anything at your home," Anspach said. "Let's say a person is pumping water from a lake to water their garden. If they're on a lakeshore, they can do that, but they also have to do something about their water intake. On Lake Bemidji, with water intake pipes, we're already seeing them start to get clogged by zebra mussels."
Kovar said there's no way to eliminate the mussels and instead, people have to adapt to them being there now.
The other species infesting some of the county's waters are faucet snails, which are hard to discover.
"Unless you know what you're looking for, it can be hard to know they're faucet snails," Kovar said. "They reproduce quite a lot and they compete with our native species for the same resources."
The most prevalent ecological problem with the snails, though, is how they act as a host to parasites.
"Those parasites can cause hemorrhaging in the stomach of waterfowl and death," Kovar said. "Many thousands of deaths are attributed to those and our native snails don't host these parasites."
The other species of concern, starry stonewort, is a micro-algae. Each strand of the algae is its own individual cell, and the species is known for those pieces to stick together, forming chains and mats.
A critical issue with the algae was how DNR officials had to learn about the plant on the fly.
"We don't know a ton about starry stonewort, because it wasn't studied well before," Kovar said. "When we were looking at how to manage it before and stop it, only one article out there even referenced it. More research is being done now on its phenology, its reproduction ability and how long it can survive out of water."
What is known is that it can grow to 10 feet in the water and causes negative impacts on recreation and ecology.
"It has a recreational impact because it can mat and then come all the way to the surface," Kovar said. "In a lake, that makes it difficult for boating. Even if you do manage to get through it with a boat, you're causing more spread, too, because you can chop off a section and those viable cells can still take root."
The environmental impacts, meanwhile, are toward other native species.
"In Beltrami County, we have more lakes with it than any other in Minnesota and we're watching how it behaves from lake to lake," Kovar said. "When we find it, it is pretty abundant and expands very quickly. We're worried about it out-competing native plants and the loss of diversity with native species."
The most notable way it impacts native vegetation is how its growth can shade out other plants, which need the sun to germinate.
In the ongoing prevention efforts, Anspach said the biggest concern for his office is boaters traveling from one body of water to another within five days.
"It's suggested to dry your watercraft for five days, or get it decontaminated," Anspach said. "Last year, we had 23.8% of our boaters going to a different water body within five days. If they're going to Lake Bemidji and then back to that lake it doesn't count, it's only if they're going to a different one."
To help in that effort, Anspach said after a boater drains their craft, they should flush out their livewell and baitwell, too.
"Sometimes all the water doesn't get drained when the plug is pulled," Anspach said. "We're focused on that behavior and it's easy to solve. Even if you don't find plants or animals, it's easy to throw some hot water through your livewell, because what you're dealing with are very small mussels or plants."
For water bodies already infested, Kovar said the DNR's effort is a mix of continuing research on management methods and educating the public on more prevention. As part of the latter work, Kovar said the agency is working across state lines and with Canadian officials to prevent species from flowing into Minnesota from outside water sources.