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California county declares emergency over 'out of control' invasive species

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Published  April 30, 2026 11:28am PDT
Wild Nature
FOX 11
article

Golden Mussel shells collected in October 2024 at a water quality station at Rough and Ready Island near Stockton in San Joaquin County, California. (Photo courtesy Elizabeth Wells, Ph. D. (DWR) via California Department of Fish and Wildlife)

The Brief

    • San Joaquin County has declared a local state of emergency to combat an infestation of invasive golden mussels that have spread rapidly across the Delta since their 2024 discovery.
    • The infestation threatens critical infrastructure, already fouling a $100 million floodgate and irrigation equipment, while posing a severe risk to the region's $3 billion agricultural industry.
    • Emergency measures prioritize funding and mitigation, including a proposal for $7.5 million to build five decontamination stations and a streamlined permitting process for faster boat inspections.

SAN JOAQUIN COUNTY, Calif. - San Joaquin County supervisors took unanimous action Tuesday to address a "local emergency" caused by the rapid proliferation of golden mussels in the Delta. 

What we know:

The invasive bivalves, first detected in North America just two years ago, are now disrupting water conveyance, farming, and natural ecosystems, according to the California Department of Fish and Wildlife.

The golden mussel is a tenacious species from Asia that survives in both fresh and brackish water. 

A single female can produce over 1 million offspring annually, leading to exponential growth that clogs pipelines and restricts water flow. 

Officials confirmed that a $100 million floodgate completed in 2024 is already infested, requiring expensive removal efforts. 

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The emergency declaration, which will be reviewed every 60 days, aims to strengthen state partnerships and protect freshwater systems, public infrastructure, and local farms.

Assemblymember Rhodesia Ransom is currently pushing a proposal to allocate $1.5 million for each of five new decontamination stations.

What's next:

The county will work with the California Department of Fish and Wildlife to implement targeted mitigation strategies. 

A key focus will be Assemblymember Ransom’s bill, which seeks to streamline the permitting process to allow water agencies to conduct faster inspections. 

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Mandates remain in effect at Northern California lakes, including Lake Tahoe, requiring strict inspection and quarantine protocols for all watercraft to prevent further inland spread.

The Source: This report is based on information from the San Joaquin County Board of Supervisors and the California Department of Fish and Wildlife. 

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