Prior Lake, north of Thetis Lake.

Public Service Announcement from CRD Parks

For Immediate Release   August 23, 2018

 Prior Lake Tests Positive for Blue-Green Algae

The Capital Regional District (CRD) advises that water samples taken from Prior Lake, located at the north end of Thetis Lake Regional Park, have tested positive for a type of blue-green algae that produces 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 and these compounds have been detected previously at Thetis Lake. 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.  There are no signs of blue-green algae at Upper or Lower Thetis Lake.