Officials in San Joaquin County declared an emergency on Wednesday due to an infestation of an invasive species of mussels, which are clogging infrastructure and damaging the environment.
In a unanimous vote, all five of the San Joaquin County supervisors voted in favor of declaring a “local emergency” over the rising number of golden mussels found in the delta.
The small bivalves appeared in the region just two years ago, marking the first time they were discovered in North America. Originally from Asia, the mussels with brown and golden shells grow up to 1.75 inches long and can reproduce at an exponential rate. The sea creatures are tenacious and can survive in both fresh and brackish waters.
Hilary Crowley, a legislative officer for San Joaquin County and member of the ad hoc committee on golden mussels, said a $100 million floodgate completed in 2024 has been infested with the invading species, requiring a expensive removal.
“A single female mussel can produce over 1 million offspring in a single year,” she said in a presentation to the supervisors.
Crowley said the mussels not only damage water infrastructure but also threaten endangered species in the region such as the delta smelt. The mussels have also reportedly started to show up in irrigation equipment that bring water from the delta to farmland, according to CalMatters.
Supervisor Paul Canepa said the problem isn’t contained to just the delta, but “anywhere the water from the Delta goes,” including holding ponds.
“This is out of control,” he said during the meeting. “And our delta being ground zero … first we thought it was just a boating issue, but it became way more than a boating issue.”
Since being discovered in the delta, the mussels have spread throughout the state, including down to the Los Angeles and San Diego area, according to a map from the California Department of Fish and Wildlife.