Yolo County declares local emergency over threat of invasive golden mussels

Yolo County’s Board of Supervisors declared a local emergency Tuesday in response to the threat of invasive golden mussels spreading through the county’s waterways, officials announced.

Yolo County authorities confirmed June 25 that the invasive freshwater mollusk, native to Asia, had been found in county waterways connected to the Sacramento-San Joaquin Delta, according to the California Department of Fish and Wildlife. The bivalve species was first detected in the Delta on Oct. 17, 2024, and has rapidly proliferated since, prompting emergency declarations last month in Sacramento, Kern and San Joaquin counties.

“Golden mussels pose a serious long-term threat to the water systems and natural resources that support communities across Yolo County and the Delta region,” Sheila Allen, Chair of the Yolo County Board of Supervisors, said in a statement. “This proclamation gives the County a stronger footing to work with our partners and seek the resources needed to protect public infrastructure, agriculture and the environment.”

Golden mussels reproduce rapidly, forming dense colonies on underwater surfaces that can clog pipes, pumps and critical water infrastructure while disrupting local ecosystems. The mollusk’s larvae are also invisible to the naked eye and can be easily transported in standing water if watercraft and equipment are not properly cleaned and drained.

How can I check my watercraft for golden mussels?

As state and local officials work to contain the spread of the mussels, they are urging boaters to follow the “Clean, Drain and Dry” procedure:

• Clean off visible aquatic plants, animals and mud from equipment before leaving the water.
• Drain all water-containing devices before leaving the water.
• Dry everything for at least five days or wipe equipment with a towel before reuse.
• Dispose of unwanted bait, worms and fish parts in the trash, and use spring or dechlorinated tap water to store live bait.

AAnyone who spots a golden mussel should report it to the California Department of Fish and Wildlife through its online Report an Invasive Species Sighting, by emailing [email protected], or by calling 866-440-9530.