VANCOUVER -- Officials in B.C.'s capital region are warning residents of a blue-green algae bloom at a lake in a regional park.

The Capital Regional District issued the warning for Elk Lake on Saturday, urging visitors to Elk/Beaver Lake Regional Park not to swim in or - more importantly given that it's January - allow pets to enter or drink from the lake, until the advisory is lifted. 

Blue-green algae can produce cyanotoxins, which can cause a range of symptoms, including headaches and abdominal pain in humans and potentially lethal liver damage in dogs, according to the CRD.

"The algae usually produce a visible blue-green sheen, which appears as surface scum on the water," the district says in its announcement. "Not all blooms are easy to see and toxins can still be present in the water even if you cannot see a bloom."

The CRD advises keeping animals on-leash when visiting the park while the advisory is in place.