Zebra mussels confirmed in Bowstring Lake in Itasca County

July 29, 2020

The Minnesota Department of Natural Resources has confirmed zebra mussels in Bowstring Lake, located mostly within the Leech Lake Reservation in Itasca County.

Itasca County invasive species staff contacted the DNR after finding two adult zebra mussels attached to old, submerged tires in separate locations outside reservation waters on the northeast side of the lake. DNR invasive species specialists determined that at least one of the mussels had likely been in the lake for more than one year.

A subsequent survey of the entire north shore of Bowstring Lake by Itasca County invasive species staff revealed a number of adult zebra mussels. Their distribution was described as “widespread but not numerous,” suggesting early detection.

Water from Bowstring Lake flows into Sand Lake and eventually into the Bigfork River and north to Hudson Bay. Zebra mussels were confirmed in Sand Lake in 2013 and have been confirmed downstream nearly 20 miles in recent years. Navigation from Sand Lake to Bowstring is not common, due to the nature of the connecting river and water levels. The DNR and Itasca County invasive species programs have paid close attention to Bowstring Lake because of its close proximity to waters where zebra mussels were previously confirmed.   

The DNR has contacted the Leech Lake Band of Ojibwe with information about the confirmed zebra mussels.

Whether or not a lake is listed as infested, Minnesota law requires boaters and anglers to:

  • Clean watercraft and trailers of aquatic plants and prohibited invasive species.
  • Drain all water by removing drain plugs and keeping them out during transport.
  • Dispose of unwanted bait in the trash.

Some invasive species are small and difficult to see at the access. To remove or kill them, take one or more of the following precautions before moving to another waterbody:     

  • Spray with high-pressure water.
  • Rinse with very hot water (120 degrees for at least two minutes or 140 degrees for at least 10 seconds).
  • Dry for at least five days.

Zebra mussels 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.

People should contact a Minnesota DNR aquatic invasive species specialist if they think they have found zebra mussels or any other invasive species.

More information is available at mndnr.gov/ais.