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DNR: Invasive starry stonewort confirmed in Pokegama Lake

Starry stonewort is a bushy, bright green algae that produces star-shaped bulbils.
U.S. Geological Survey
Starry stonewort is a bushy, bright green algae that produces star-shaped bulbils.

The invasive algae was confirmed by the Department of Natural Resources after a report from Itasca County staff.

GRAND RAPIDS — The Minnesota Department of Natural Resources confirmed the presence of starry stonewort in Pokegama Lake.

Specialists from Itasca County and the DNR found the invasive algae interspersed with native plants on and around a boat ramp on the southwest end of the lake while investigating a report from Itasca County staff, according to a June 7 news release.

Follow-up surveys are being conducted to determine the species distribution.

Starry stonewort is usually identified by its star-shaped white bulbils, which are visible earlier than usual this year, possibly due to the warm winter. It can form dense mats, which interfere with recreational uses of lakes and compete with native plants. Starry stonewort is most likely spread by fragments that have not been properly cleaned from trailers, boats, docks, anchors or other water-related equipment.

Last month the invasive algae was also found in Middle Cullen Lake near Nisswa. It has now been confirmed in 30 Minnesota water bodies since 2015. Other infested waters in Northern Minnesota include Lake Bemidji, Cass Lake, Leech Lake, Upper Red Lake, Blackduck Lake, Turtle (Big Turtle) Lake and Lake Winnibigoshish.

Starry stonewort has never been eradicated from a U.S. lake or river, but treatment or careful removal can help reduce the risk of spread and alleviate the impact on recreational activities. The DNR said early detection is key to effective management.

The algae looks like some native aquatic plants, and the DNR has information on identifying it. If you think you've found starry stonewort or another new invasive species, report it to the DNR

To help prevent the spread of aquatic invasive species, remember to clean, drain, dry and dispose, even when leaving or entering waters that are not known to have invasive species. The DNR says to:

  • Clean watercraft, trailers and gear to remove aquatic plants and prohibited invasive species.
  • Drain all water and leave drain plugs out during transport.
  • Dispose of unwanted bait in the trash.
  • Never release bait, plants or aquarium pets into Minnesota waters.
  • Dry docks, lifts and rafts for 21 days before moving them from one water body to another.

These additional steps reduce the risk of spreading aquatic invasive species:

  • Decontaminate watercraft, trailers and gear at free decontamination stations.
  • Spray watercraft, trailers and gear with high-pressure water or rinse with very hot water.
  • Dry watercraft, trailers and gear for at least five days before using in another water body.