Toxic Algae Persists In Fremont Lakes

FREMONT, CA — East Bay Regional Park District officials have "danger" advisories in place for several East Bay lakes due to the lingering presence of blue-green algae, aka cyanobacteria.

"The advisories typically transition up and down throughout the year based on many factors, ranging from no advisory, caution, or danger," said Dave Mason, public information supervisor of the East Bay Regional Park District.

Park officials' current danger-level advisories include Lago Los Osos and Horseshoe Lake / Niles Swim Beach at Quarry Lakes Regional Park in Fremont.

The "danger advisory" warns that "toxins from algae in this water can harm people and animals." Specifics of the advisory include staying out of the water and not touching "scum in the water or on the shore"; not drinking the water or using it for cooking; and not allowing pets to go into or drink the water, according to park officials.

"Certain conditions – low water levels, limited water circulation, increased temperature and light, among other factors – can cause blue-green algae to bloom and, in some cases, release toxins," stated park officials. "Scientists do not know what causes the blue-green algae to become toxic."

The East Bay Regional Park District had its first-ever toxic algae bloom in 2014, they said.

Red signs are posted at Quarry Lakes to alert visitors about the presence of blue-green algae.

For more information about the "Current Water Quality Conditions" of East Bay lakes, go here.

A PDF brochure about blue-green algae, courtesy of the East Bay Regional Park District, is available here.