RESOLVED: Blue-Green Algae Bloom at Thetis Lake Regional Park

Nov 04, 2019 (updated Dec 05, 2019, 10:11am)

As of Dec 5, the advisory has been lifted at Thetis Lake. However, blue-green algae blooms are unpredictable and may occur at any time.

The CRD, in consultation with Island Health, has lifted the blue-green algae advisory at Thetis Lake, located in Thetis Lake Regional Park. Water samples collected indicated a “below detection limit” result for cyanotoxins. The extended absence of blue-green scum combined with test results are good indicators that the bloom is over. 

Park users are reminded to watch for the distinctive blue-green sheen that can appear on the lake surface at any time. These blue-green algae are known toxin producers. Ingesting water containing the blue-green algae 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 active alerts. To learn more about blue-green algae visit these sites:

• Healthlink BC

• Health Canada

Thetis Lake Regional Park map (PDF)