Cyanobacteria makes its summer visit

Jul 24, 2017

Cyanobacteria, commonly known as blue-green algae, is once again affecting bodies of water in the area, and local Public and Environmental Health officials are advising people to avoid contact with this potentially toxic bacteria.

Warm water and abundant nutrients can cause cyanobacteria to grow more rapidly than usual causing “blooms.” Most species of cyanobacteria do not affect animals or people but some are capable of producing toxins that can be harmful. Dogs and children are especially vulnerable because of their smaller body size and tendency to stay in the water for longer periods of time.

According to a recent warning from public health agencies in Humboldt, Mendocino, and Lake Counties, the presence of cyanobacteria has been confirmed in some bodies of water bodies in Mendocino, Humboldt, and Lake counties including the South Fork of the Eel River, Van Duzen River, Trinity River, Clear Lake and Lake Pillsbury.

Officials recommend recreational users of freshwater in the region follow guidelines to prevent the harmful blooms, they include:

-being conservative with water use, fertilizers and pesticides on lawns, gardens or agricultural operations.

-Avoiding nutrient runoff by recycling any “spent” soil by tilling it back into gardens, or protecting it from rainfall.

-Creating shade and filtering out nutrients by planting or maintaining native plants around river banks.

-Inspecting and pumping out septic systems every three to four years, and preventing erosion around construction and logging operations.

Cyanobacteria looks like dark green, blue-green, black, orange or brown scum, foam or mats on the riverbed or floating on the water. To learn more about cyanobacteria and algae on the South Fork Eel River, visit