Invasive Mussel Found In CA Poses Immediate Threat To All State Waters

SACRAMENTO, CA — Golden mussels, an invasive species that poses a significant immediate threat to the ecological health of the Sacramento-San Joaquin Delta and all waters of the state, water conveyance systems, infrastructure and water quality, were recently discovered in the Port of Stockton, the California Department of Parks and Recreation said Thursday.

The mussels were found during routine inspections by California Department of Water Resources and are likely to spread throughout the Delta and through the water conveyance systems associated with it, officials said.

Suspected golden mussels (Limnoperna fortunei) were also identified at O’Neill Forebay in Merced County and were being tested for confirmation.

It is the first known occurrence of golden mussels in North America. The species is native to the rivers and creeks of China and Southeast Asia. State officials believe the mussels were likely introduced to California by a ship traveling from an international port.

Species confirmation was pending Thursday on additional golden mussels found downstream from the Port of Stockton.

Without containment, they are likely to spread to other freshwater bodies in California, and to other ports and inland waters of North America and abroad, state officials said.

"In waterways where this species is present, heavy encrustations of golden mussels have blocked municipal and industrial water intakes, necessitated ongoing biofouling removal, harmed native species in the ecosystem, increased water clarity due to intense filter feeding, and diminished water quality," state officials said.

The Department of Water Resources is now conducting boat inspections at O’Neill Forebay to reduce the spread of the aquatic invasive species which are similar in appearance to quagga and zebra mussels — still considered a serious threat to California's waters and fisheries.

The California Department of Fish and Wildlife continued to work with state, local and federal agencies to enhance monitoring efforts, communicate additional detection and response information, and coordinate potential next steps.

"The California Natural Resources Agency and its partners call upon everyone working and recreating in waters of the state to clean, drain and dry watercraft and equipment every time it is removed from a waterbody," state officials said. "This simple measure has served to prevent spreading quagga and zebra mussels and is equally effective in stopping the overland spread of golden mussels."

The public is asked to report organisms observed in California suspected to be golden mussels to CDFW’s Invasive Species Program through an online form, via email to invasives@wildlife.ca.gov or by calling the hotline at 866-440-9530.

"Include the specific location of the observation, and at least one clear close-up photograph of the organism, and your contact information."