SMDHU Cautions Residents And Visitors To Ten Mile Bay After Blue-Green Algae Bloom Is Confirmed

Blue-green algae in Sullivans Creek, Canberra. Photo by Gregory Heath, CSIRO

An update from the Simcoe Muskoka District Health Unit:

A confirmed blue-green algae bloom is impacting a shallow bay on the eastern end of Ten Mile Bay, in the Township of Lake of Bays, and residents and visitors are being reminded to take precautions.

The Simcoe Muskoka District Health Unit is asking residents and visitors to exercise care where blue-green algae is visible and to take the following measures:

  • Do not use the lake water for the preparation of infant formula
  • Do not allow pets or livestock to drink or swim in the water where an algae bloom is visible
  • Be cautious about eating fish caught in water where blue-green algae blooms occur
  • Do not use herbicides, copper sulphate or other algaecides that may break open algae cells and release toxins into the water
  • Avoid swimming and other water sport activities where an algae bloom is visible.

Blooms may make the water look bluish-green, or like pea soup or turquoise paint. Many species of blue-green algae (also called cyanobacteria) have the potential to produce toxins that are harmful to the health of humans and animals. Symptoms from consuming toxins from a blue-green algae bloom can include headaches, fever, diarrhea, abdominal pain, nausea and vomiting, and can be more serious if water is swallowed in large quantities.

The health unit and the Ministry of Environment, Conservation and Parks will continue to work together to monitor the algal bloom and updates will be provided on our website ( as we receive new information.

To learn more about blue-green algae visit the health unit website at, or call Health Connection weekdays from 8:30 a.m. to 4:30 p.m. at 705-721-7520 or 1-877-721-7520.


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