About Golden Mussels

Background:

• Discovery in California: In October 2024, golden mussels were first identified in the Port of Stockton by the California Department of Water Resources. Subsequent findings at O’Neill Forebay in Merced County are pending genetic confirmation. This marks the first known occurrence of golden mussels in North America. 

• Origin and Spread: Native to rivers and creeks in China and Southeast Asia, golden mussels have established populations in regions including Hong Kong, Japan, Taiwan, Brazil, Uruguay, Paraguay, and Argentina. Their introduction to new areas is often attributed to biofouling on ship hulls or ballast water discharge. 

 

Ecological and Infrastructure Impact:

• Ecosystem Disruption: Golden mussels can form dense colonies that outcompete native species, leading to significant alterations in local biodiversity. Their filter-feeding behavior increases water clarity, which can disrupt existing aquatic ecosystems.

• Infrastructure Challenges: These mussels are known to clog water intake structures, affecting municipal and industrial water systems. The resultant biofouling necessitates frequent and costly maintenance. 

 

Preventative Measures:

• Mandatory Vessel Inspections: Starting April 14, 2025, all trailered or motorized vessels aiming to launch at Folsom Lake and Lake Clementine must undergo a mandatory 30-day quarantine with a red cable seal applied. From May 14, 2025, vessels can opt for decontamination to receive a green cable seal, allowing immediate launch. 

• Clean, Drain, Dry Protocol: Boaters are urged to meticulously clean, drain, and dry their vessels after each use to prevent the spread of golden mussels. This protocol is crucial in minimizing the risk of transferring invasive species between water bodies. 

 

Reporting and Resources:

• Sightings: If golden mussels are observed, it’s imperative to report them promptly. 

• Further Information: For comprehensive details on identification, impacts, and prevention strategies, refer to the California Department of Fish and Wildlife’s dedicated page on golden mussels. 

 

Implementing these measures is vital to curbing the spread of golden mussels and safeguarding California’s aquatic environments and infrastructure.