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Volunteers search 187 Minnesota lakes, find only one with invasive algae

Starry stonewort invasive algae. Forum News Service file photo1 / 2
Starry stonewort invasive algae. Forum News Service file photo2 / 2

PARK RAPIDS, Minn. —  After scouring 187 lakes in Minnesota, a team of 225 trained volunteers found only one lake that had the invasive algae called starry stonewort.

It was Wolf Lake in Hubbard County in north-central Minnesota.

During a follow-up survey in the lake, DNR invasive species specialists found a one-third-acre bed of starry stonewort at an undeveloped access off a township road.

Boat inspections have been expanded and treatment options are being considered, along with more follow-up surveys to watch for the invasive algae in other parts of the lake.

Starry stonewort has never been eradicated from any U.S. lake, but treatment can help reduce the risk of spread and provide nuisance relief for water-related recreational activities, according to the Minnesota Department of Natural Resources.

Dr. Ken Karol with the New York Botanical Garden provided scientific verification of the starry stonewort sample from Wolf Lake. Volunteers submitted samples from several other lakes during the search event that turned out to be chara, a native alga that looks similar to starry stonewort.

This year’s search results mirror the 2017 inaugural event. Last year, 200 volunteers searched 178 lakes and found starry stonewort in one. There are now 14 lakes in Minnesota where starry stonewort has been confirmed.