Noxious algae prompts warnings for visitors to stay out of water at Central Valley reservoir

Shae Hammond/Bay Area News Group
·2 min read

California officials warned of dangerous algae growing in a central San Joaquin Valley waterway on Friday just days before people head out to play in the water on the Fourth of July.

The Department of Water Resources said people should avoid contact with water at San Luis Reservoir in Merced County until further notice after the discovery of blue-green algae.

People should also avoid eating fish or shellfish from the lake, officials said. Pets should also be kept away from the water.

The lake, the O’Neill Forebay and other water in the area can attract people from Merced, Fresno, Madera and multiple other counties who may be looking to fish or cool off.

Officials said the blue-green algae warning is in place for the lake, but the O’Neill Forebay is considered safe.

Boating will be allowed, but swimming and other activity in the lake are not considered safe, officials said in a news release.

Exposure to toxic blue-green algae — known as cyanobacteria — can cause eye irritation, allergic skin rash, mouth ulcers, vomiting, diarrhea, and cold- and flu-like symptoms.

Pets are especially in danger because they are more likely to drink the water or lick it off of their fur, officials said.

The algae can be blown around the waterway by changes in the wind, the release said. The algal bloom can also take different forms, like mats, scum or foam at the surface and along the shoreline. It can be blue, green, white or brown.

  • Keep pets and livestock away from the water. Rinse pets in clean water to remove algae from fur.

  • Avoid wading, swimming or skiing in water with blooms.

  • Do not drink, cook or wash dishes with untreated surface water.

  • Do not eat mussels, other bivalves or fish collected from these areas.

  • Get medical treatment immediately if you think that you, others or pets and livestock might have been poisoned.