In Beltrami County, Minnesota, infested lakes pose environmental problems


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

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

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

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A lake determined to be infested begins with the county. Bruce Anspach, Lake Invasive Species Technician for Beltrami County, said that in the event of an infestation, a report should be sent to MNR.

The DNR will then send a manager to visit the site with Anspach for confirmation before classifying it as an infested water body.

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

Of the three, Nicole Kovar, MNR’s aquatic invasive species specialist, said zebra mussels are the most harmful. Mussels, which are no more than two inches in size, consume by attracting whatever is nearby.

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


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

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

According to Kovar, an adult female mussel can lay up to a million eggs per summer. At the start of their life, mussels are microscopic for almost three weeks while the shells are being 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 is the most harmful species in the United States for its effect on the ecosystem. But now with the ecosystem there can be economic impacts, as they can also clog the water supply pipes. They prefer shaded areas, in order to be able to colonize these pipes. . “

“It makes a difference in harvesting the bait and using the water for whatever is in your house,” Anspach said. “Let’s say a person pumps water from a lake to water their garden. If she’s by a lake, she can do it, but she also has to do something about her water intake. On Lake Bemidji, with water intake pipes, we can already see them starting to get clogged with zebra mussels. “

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

The other species that infest some of the county’s waters are tap snails, which are difficult to find.

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

The most common ecological problem with snails, however, is how they act as host to parasites.

“These parasites can cause bleeding in the stomachs of waterfowl and death,” Kovar said. “Thousands of deaths are attributed to it and our native snails do not harbor these pests.”

The other species of concern, the stellate strophée, is a microalgae. 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 Nymore's water access alert boaters to invasive species in the lake and remind them to help stop their spread.  (Jillian Gandsey / Bemidji Pioneer)

Signs near Nymore’s 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 MNR officials should learn about the plant on the fly.

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

What we do know is that it can reach 10 feet in the water and have negative impacts on recreation and ecology.

“It has a recreational impact because it can line and then rise to the surface,” Kovar said. “In a lake, that makes it difficult to navigate. Even if you manage to cross it with a boat, you also cause more spread, as you can cut a section and those viable cells can still take root. “

The environmental impacts concern other native species.

“In Beltrami County we have more lakes than any other in Minnesota and we are watching how it behaves 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 impact on native vegetation is how its growth can shade other plants, which need sunlight to germinate.

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

“It is suggested that you dry your boat for five days or have it decontaminated,” Anspach said. “Last year, we had 23.8% of our boaters who went to another body of water in five days. If they go to Lake Bemidji and then return to that lake, that doesn’t matter, c It’s only if they go different. “

To help with that effort, Anspach said after a boater empties his boat, he should also empty his fishpond and bait.

“Sometimes all the water doesn’t drain out when the cap 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 fish tank because you are dealing with very small mussels or plants. “

For already infested water bodies, Kovar said the DNR effort is a mixture of continued research into management methods and educating the public on further prevention. As part of the latter work, Kovar said the agency was working across state borders and with Canadian officials to prevent species from entering Minnesota from outside water sources.

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