Napa supervisors signal intent to adopt ordinance to inspect boats for invasive mussels at Lake Berryessa

The Napa County Board of Supervisors on June 24 signaled its intent to adopt an ordinance authorizing inspections of watercraft at Lake Berryessa to prevent the spread of invasive golden mussels.

The effort follows a technical presentation by Martin Peralez, a PhD aquatic ecologist with the Napa County Resource Conservation District, who told the board the golden mussel has been newly detected in California's Sacramento–San Joaquin Delta and poses both ecological and infrastructure risks. "These mussels are relatively small. They're in the inch to inch and a half range," Peralez said, adding that researchers detected the species in the Delta "near Stockton at Ruffin Ready Island." He warned the mussels reproduce quickly, can spread as attached adults or as microscopic free‑swimming larvae called veligers, and can survive out of water for weeks.

The ordinance would add a chapter to the county code (chapter 6.02) authorizing county inspectors, concession staff and law enforcement to stop and inspect boats, trailers and other watercraft entering Lake Berryessa, improve tag and decontamination tracking and create enforcement tools including fines and a misdemeanor for deliberately avoiding inspections.

Why it matters: Golden…