Blue-Green Algae Bloom at Prior Lake (Thetis Lake Regional Park)

Aug 29, 2019

There is a visible blue-green algae bloom at Prior Lake. People and pets should avoid swimming in the lake.

The Capital Regional District (CRD) advises, in consultation with Island Health, that there is a visible blue-green algae bloom at Prior Lake, located at the north end of Thetis Lake Regional Park. Blue-green algae can produce cyanotoxins. Visitors are advised to avoid swimming at Prior Lake and to keep animals on a leash to prevent them from drinking or swimming in the lake until the advisory has been lifted.

The algae usually produce a visible blue-green sheen, which appears as surface scum. Not all blooms are easy to see and toxins can still be present in the water even if you cannot see the blooms. Blooms are unpredictable and may occur at any time.

These algae are known toxin producers. Ingesting water containing these cyanotoxins may cause a range of symptoms, including headaches and abdominal pain in humans, and can lead to lethal liver damage in dogs.

Please visit and Twitter @crd_bc for updates on the status of the algae bloom. To learn more about blue-green algae visit these sites:

Healthlink BC

Health Canada

Thetis Lake Regional Park map (PDF)