Zebra mussels have been found in the Minnesota River, adding yet another major waterway to the state Department of Natural Resources' infested-waters list.
The invasive species can compete with native species for food and habitat, cut the feet of swimmers, reduce the performance of boat motors and cause expensive damage to water intake pipes.
To reduce the risk of spreading invasive species, activities such as bait harvest, commercial fishing and water use are managed differently in waters that have been declared infested.
Last September, the DNR confirmed zebra mussels in Lac qui Parle, a Minnesota River reservoir, the agency said in a news release Thursday. Recent surveys confirmed adult zebra mussels behind the Granite Falls dam and zebra mussel larvae at four of seven sites on the Minnesota River, from Montevideo to near New Ulm.
No larvae were detected at survey sites near St. Peter, Chaska, or Minneapolis and St. Paul.
Based on individual captures in 2016 and 2017, the Minnesota River also is being added to the infested-waters list for bighead carp and grass carp from Granite Falls to the confluence with the Mississippi River.
The DNR already has been in contact with businesses such as commercial anglers and bait harvesters that will be affected by the designation.
To protect the state's waterways, Minnesota law requires boaters and anglers to clean watercraft of aquatic plants and prohibited invasive species; drain all water by removing drain plugs and keeping them out during transport; and dispose of unwanted bait in the trash.