California Golden Mussels: New Rules & What Boaters Need To Know

As invasive golden mussels spread through California waterways, BoatUS and recreational boating advocates are pushing for effective, consistent prevention measures that protect both the environment and boating access.

BoatU.S. is lending its political muscle to address California’s growing mussel infestation as the state expands existing laws passed to halt invasive quagga and zebra mussels to now encompass all marine invasives. Whatever inspection and decontamination requirements emerge from the lawmaking, recreational boaters will need to play a critical role in combatting the invaders.

Heads up: Anyone planning to go boating next year in California needs to comply with “Clean, Drain, Dry” decontamination protocols.

“We’re trying to ensure that the boaters who do their part are not unduly burdened as we work to prevent infestations and prevent spread,” explains David Kennedy, manager of BoatU.S. Government Affairs. “Our message to lawmakers is we boaters will do our part, but the process must also address the sources of infestation, which appear to be ballast water of ships from overseas.”

What Are Golden Mussels And Why Are They A Threat?

Golden mussels are native to rivers and lakes in Southeast Asia. Although invasive mussels such as quagga and zebra are a growing problem in at least 33 states, golden mussels have so far only been reported in California. Similar in appearance to the more commonly known quagga and zebra, the 3/4- to 1-1/4-inch golden mussels are more threatening because they can establish their dense, hornet-nest-like clusters in waters with wider temperature and salinity ranges.

They were first detected in October 2024 near Stockton, some 80 nautical miles inland from the Pacific Ocean via the California Delta. Officially named the Sacramento-San Joaquin Delta, the sprawling 1,100 square-mile estuary is where five rivers merge and flow into San Francisco Bay. The voracious bivalve mollusks consume massive amounts of plankton, which starves native fish and aquatic organisms. Their nutrient-heavy excrement also encourages harmful algal blooms.

As of autumn 2026, golden mussels have been confirmed in more than 50 locations stretching hundreds of miles from Sacramento to San Diego. Zebra and quagga mussels, also native to Southeast Asia, were first discovered in state waters in 2007 and have spread to multiple Southern California rivers and lakes, where they create similar threats to native marine life and the recreational boating lifestyle.

How California Mussels Are Affecting California Boating Access

California is a large state with more than 3,000 named bodies of water. The agencies and utility companies that manage the state’s reservoirs and natural lakes have broad authority over the bodies of water – including shutting them down to recreational boating if they determine the water body is threatened. To prevent further spread of the golden mussels, that’s exactly what many managers did, to the chagrin of California’s renowned trailerboat culture that favors enjoying a variety of aquatic playgrounds.

“We saw a rapid response with a variety of actions including restrictions and bans that first year,” says Jerry Desmond, a legislative advocate working with BoatU.S. and our partner advocacy group Recreational Boaters of California to defend boater rights in this legislative mussel fight. “From there, piecemeal efforts established boat inspection and decontamination procedures. We advocate for comprehensive, uniform statewide standards and plans.”

California’s Response And BoatUS Advocacy Efforts

The California Department of Fish and Wildlife was expected this fall to revise its existing regulations established to combat quagga and zebra mussels to include golden mussels (and future aquatic invasive species, or AIS, while also expanding lake by lake enforcement and prevention measures such as mandatory watercraft inspections for vessels docked in infested waters for four or more nights.

BoatU.S. and RBOC are part of a coalition supporting the new regulations, stating in a letter to legislators the new rules will “strengthen California’s ability to rapidly prevent, mitigate, and control invasive golden mussels in water supply systems and public waterways.” The plan includes state funding for three years from $20 million appropriated to CDFW in the 2025 Budget Act.

At the federal level, California Senator Adam Schiff introduced the Golden Mussel Eradication and Control Act of 2026 (S. 4603) that would direct $15 million annually through 2030 to bolster local California task force eradication efforts, primarily targeting the Sacramento-San Joaquin Delta. That federal bill remained in limbo as this issue went to press.