In the ebb and flow of blue-green algae in regional lakes Thetis, Durrance, Beaver and Prior lakes are all unsafe for swimming, according to the Capital Regional District that routinely tests water quality.

The CRD, in consultation with Island Health, issued an advisory for blue-green algae blooms in Thetis Lake, located in Thetis Lake Regional Park on Oct. 1.

There were already warnings in place for nearby Prior Lake, Durrance Lake in Mount Work Regional Park and Beaver Lake located in Elk/Beaver Lake Regional Park.

Visitors are advised to avoid contact with blue green algae and to keep animals on a leash to prevent them from drinking or swimming in the lakes until the advisory is lifted. The algae can produce cyanotoxins and ingesting them can cause a range of symptoms, including headaches and abdominal pain in humans, and can lead to lethal liver damage in dogs.

The algae usually produce a visible blue-green sheen, which appears as surface scum on the water. Not all blooms are easy to see and toxins can still be present in the water even if the bloom isnB次元官网网址檛 visible.

Blooms are known to be unpredictable. Visit  for updates.