Following a warning from California water quality officials to avoid the Klamath River due to toxic algal blooms, the Yurok Tribe on Monday said contamination levels exceed standard health thresholds by up to 30 times.

During its weekly water quality tests Sept. 12-13, the Yurok Tribe Environmental Program detected Microcystis aeruginosa, or blue-green algae, levels that were 10 to 30 times greater than common health standards deem safe, according to a press release from the Yurok Tribe. Algal levels were at their highest since the tribe began testing in 2006, according to the press release.

According to Tribal Chairman Thomas P. O’Rourke Sr., algae indicates poor water quality, negatively affecting the salmon population and the whole Klamath River ecosystem.

“It’s frustrating that even with this year’s above-average rainfall and snowpack, the river conditions are still compromised,” O’Rourke said in a written statement Monday.

This year the toxin first showed up in late August, prompting tribal and public health officials to warn residents to avoid a 200 mile stretch of river below the lower Klamath dams.

Cyanobacteria appears as bright green in the water and can accumulate on shore. It can cause eye irritation, allergic skin rash, mouth ulcers, vomiting, diarrhea and cold-like symptoms as well as liver failure, nerve damage and death in rare situations, according to the California Water Quality Control Board.

People should avoid swimming or wading in water containing algae blooms, scums or mats. Untreated water from those areas should not be used for drinking, cooking or washing dishes — common water purification methods do not remove toxins.

People should not consume mussels or other bivalves collected from contaminated water and limit or avoid eating fish.

Pets and livestock should avoid drinking the water, swimming through algae scums or mats or licking their fur after going in the water. People should rinse their pets in clean water to remove algae from fur.

For more information about algae contamination on the Klamath River, visit