Sooke waters have taken on a tropical hue, thanks to a blue-green algae bloom in the harbour and basin.
The bloom is natural, non-toxic and poses no threat to humans, dogs or fish.
“It’s a totally harmless species,” said Nina Nemcek, phytoplankton biologist with Fisheries and Oceans Canada.
The federal department collected samples from the Sooke Harbour and Sooke Basin this week after receiving reports of turquoise waters. Nemcek identified the culprit as coccolithophore, a single-celled phytoplankton.
The milkiness of the water is caused by the phytoplankton’s calcite shell, which is similar to limestone.
It’s a common species, Nemcek said, but more commonly seen offshore or in fjords. It’s a different species from the blue-green algae that prompts health warnings in lakes during warm weather, she said.
It’s impossible to predict when a bloom will occur, but cooler, windier weather last week followed by sunny skies created the right food and light conditions for the algae to flourish, she said.
“They have the perfect combination of nutrients and light, which is what all phytoplankton want. These ones in particular are out-competing some of the other algae right now,” she said.
“They’re very happy.”
Mayor Maja Tait, who has lived in Sooke for 10 years, said it’s the first time she has seen the basin and harbour turn turquoise. But others have reported seeing the phenomenon before, she said.
It’s unknown how long the bloom will remain. “It’s unpredictable,” Nemchek said. “It will be up to the weather and the tides.”
