Folsom, California – A potentially devastating invasive species has made a troubling appearance in Southern California. On Tuesday, California State Parks officials at Folsom Lake State Recreation Area discovered several live golden mussels attached to a boat during an inspection at Beals Point — the first confirmed infestation at the lake. The vessel recently traveled through the Sacramento-San Joaquin Delta and was immediately quarantined for further decontamination.
The discovery marks the latest escalation in California’s battle against golden mussels (Limnoperna fortunei), a fast-spreading aquatic invader first detected in the Delta in October 2024. Native to Asia, golden mussels have proven exceptionally resilient, capable of thriving in a wide range of temperatures and salinities. Their presence now threatens California’s water infrastructure, fisheries, and economy.
“Thanks to this new program and the diligent work of our inspection team, we prevented this vessel from ever touching the water, which could have had catastrophic consequences,” said Mike Howard, Superintendent of Folsom Lake State Recreation Area. “This validates exactly why the inspection and quarantine program is critical.”
The program in question — a mandatory vessel inspection and 30-day quarantine policy — was implemented at Folsom Lake on April 14 in coordination with the Bureau of Reclamation. Since then, nearly 5,000 boats have been under inspection. Vessels that pass are sealed with a watercraft band and must remain out of the water for 30 days before being cleared for launch.
Golden mussels, which resemble the better-known zebra and quagga mussels, are notorious for clogging water pipes, damaging boats, and disrupting aquatic ecosystems. Once established, they are nearly impossible to eradicate. Their filter-feeding behavior starves native fish species, and they contribute to toxic algal blooms — often resulting in closures of recreational waterways and long-term ecological damage.
In response, the state has launched a coordinated Golden Mussel Response Framework led by a task force of agencies, including the California Department of Fish and Wildlife (CDFW), Department of Water Resources (DWR), and California State Parks. The plan focuses on prevention, containment, and public education.
“The discovery of golden mussels in California is a serious challenge that requires coordinated action and long-term commitment,” said CDFW Director Charlton Bonham.
To support local efforts, CDFW is offering $1 million in grants to boating facility operators to help expand inspections and prevention programs. Meanwhile, reservoir managers across the state are adjusting their boating rules in preparation for summer, urging boaters to “Clean, Drain, and Dry” their vessels to curb the spread.
With recreational boating season ramping up, officials warn that vigilance is key. As golden mussels tighten their grip on the state, California faces a race against time to protect its waters.
