Algae warning at Fernan Lake

People recreating at Fernan Lake east of downtown Coeur d’Alene are being advised to avoid a bloom of blue-green algae. The naturally occurring bacteria can produce toxins harmful to humans and animals.

The Panhandle Health District and the Idaho Department of Environmental Quality issued a health advisory for the lake Wednesday. People should avoid swallowing or inhaling water and avoid direct contact with water containing visible algae, the agencies said. Children and pets are particularly susceptible.

The toxins can’t be removed by boiling or filtering water. Anyone who drinks or swims in water containing high concentrations of the cyanobacteria or cyanobacterial toxins may experience gastroenteritis, skin irritation, allergic responses or liver damage, according to the Centers for Disease Control and Prevention.

Fish caught for consumption should first have all fat, skin and organs removed before cooking, as toxins are most likely to collect in those tissues, health officials said.

Algae blooms can occur in waters with high levels of nutrients, such as phosphorus and nitrogen. Above-average rain in June and rapid warming of the lake water recently created favorable bloom conditions, officials said.

Blue-green algae blooms often cause thick green mats along shorelines.