An 'out of control' species of mussel is threatening California's water infrastructure

An invasive species of mussel is becoming more of a concern in California as it overtakes ecosystems and impacts infrastructure, according to officials.

Golden mussels, native to China and Southeastern Asia, were first detected in October 2024 by California Department of Water Resources staff who were conducting routine operations in the Port of Stockton, a CDWR spokesperson told ABC News. The discovery was the first known occurrence of golden mussels in North America.

Since then, the mussels have spread quickly up and down the West Coast -- to the north, in the Bay Area, and to the south down to Los Angeles and San Diego, according to a map from the California Department of Fish and Wildlife. The species are highly efficient filter feeders and form dense colonies, according to the CDWF.