Gallons upon gallons of water were “vacuumed” up at Turtle Lake on Monday as part of an operation to filter out a recently discovered invasive species.
Staged near a boat access where an infestation of starry stonewort was discovered, Monday’s procedure on this lake north of Bemidji included the use of a vacuum to suck up water into a giant bag. Vegetation and mud potentially carrying the starry stonewort fragments were caught in a mesh inside the bag, while the water was allowed to flow back into the lake.
“The bag fills with water and everything flows in, like sediment and plants. All of the sediment gets caught while the water flows back into the lake,” said Mike Bolinsky, Region 1 watercraft inspection supervisor for the Minnesota Department of Natural Resources. “This is the first time it’s being used in Minnesota. Using it in other locations will be mainly dependent on what the infestation looks like on various lakes.”
The DNR has contracted Aquatic Restoration Service of Winsted for the project. Tim Smith, company co-owner, the dewatering bag process in the past has been mainly used for stormwater treatment rather than invasive species.
After the removal of the vegetation, Bolinski said a copper-based herbicide will be applied in the area in an effort to kill any of the species that may be left. The DNR said the boat access is expected to reopen before Labor Day.
The work on Turtle Lake comes after the infestation of starry stonewort was discovered earlier this month. Because of native vegetation in Turtle Lake, the species was unable to spread very far, said Bruce Anspach, Beltrami County aquatic invasive species coordinator, allowing the DNR to install a curtain around the access and for the treatment to take place.
Turtle Lake’s infestation is one of four in the state, with other cases discovered in Upper Red Lake, Cass Lake and Lake Koronis. In the northeast section of Cass Lake, the DNR has confirmed starry stonewort among heavy native growth near the Knutson Dam on the Leech Lake Reservation.
The species, native to areas spanning from Europe to China, is a grass-like algae that can produce dense mats, which are able to interfere with the use of the lake. The algae is also able to choke out native plants.
The state’s first confirmed infestation was last year in Lake Koronis near Paynesville.
According to Anspach, the stonewort may be spreading by way of watercraft trailers rather than the boats themselves.
“What we’ve been finding is it’s always appeared in shallow waters. The trailers can go into the vegetation and pull some of the vegetation back out,” Anspach said. “Most people do a good job in pulling that off, but the species is a really thin and fragile plant. It can break and a person might not get it all. When it’s in the sun, it can become powdery, too.”
“Be diligent with the trailers,” Bolinski said. “Take a little extra time when you’re pulling the boat out and look at the wheel wells and axles.”
The DNR is reminding boaters to clean all aquatic plants and animals from watercraft, drain all water by removing drain plugs and keeping the drain plugs out while transporting and disposing of unwanted bait in the trash.