ST. PAUL — The Minnesota Department of Natural Resources has confirmed the invasive algae starry stonewort in a section of the Mississippi River in Beltrami County, between Wolf Lake and Andrusia Lake.

This stretch of the Mississippi River is completely within Leech Lake Band of Ojibwe boundaries. Staff from the Leech Lake Band’s Department of Resource Management reported the potential discovery of starry stonewort at a resort on the Mississippi River. Beltrami County Environmental Services staff visited the site and verified the presence of starry stonewort by observing the distinctive star-shaped bulbils characteristic of this alga, a release said.

Starry stonewort was confirmed in Wolf Lake, upstream of this section of the Mississippi, in 2018. It was confirmed further downstream in Cass Lake in 2016.

The DNR Invasive Species Program is working with the Leech Lake Band of Ojibwe to determine the extent of the starry stonewort and pursue management options. Funds are available for an immediate response that could include hand pulling, herbicide applications and other methods as appropriate, the release said.

Starry stonewort has never been eradicated from any U.S. lake or river, but treatment or careful removal can help reduce the risk of spread and reduce adverse impacts on water-related recreational activities. Early detection is key to effective management.

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With the addition of this stretch of the Mississippi River, starry stonewort has now been confirmed in 19 water bodies in Minnesota. It was first confirmed in Minnesota in 2015.

In late summer and early fall, starry stonewort’s small white star-shaped bulbils become more visible, making it easier to distinguish from other aquatic plants. Information on how to identify starry stonewort can be found on the DNR’s website. If people think they’ve found starry stonewort or any other invasive species new to a lake or river, they should report it to the DNR by contacting the area invasive species specialist.

Starry Stonewort begins growing around mid June and can reach up to 6 inches to a foot below a lake’s water surface by late summer. (Annalise Braught | Bemidji Pioneer)
Starry Stonewort begins growing around mid June and can reach up to 6 inches to a foot below a lake’s water surface by late summer. (Annalise Braught | Bemidji Pioneer)

Starry stonewort is an alga that looks similar to native aquatic plants and can form dense mats, which can interfere with the use of a lake and compete with native plants. It is most likely spread when fragments have not been properly cleaned from trailered boats, personal watercraft, docks, boat lifts, anchors or other water-related equipment.

The DNR reminds boaters and anglers to follow Minnesota laws to prevent the spread of aquatic invasive species:

  • Clean aquatic plants and animals from watercraft.
  • Drain all water by removing drain plugs and keep drain plugs out while transporting watercraft.
  • 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, especially after leaving infested waters:

  • 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.

Details about starry stonewort and other aquatic invasive species are available at mndnr.gov/ais.