The golden mussel arrived in California without warning. The first confirmed North American detection of Limnoperna fortunei came in October 2024, when specimens were found in the Sacramento-San Joaquin Delta near Stockton and at O’Neill Forebay.
Within a year, reporting said the species had spread throughout the entire distribution system of the Arvin-Edison Water Storage District in Kern County. The response was a 30-day chemical treatment costing about $3 million.
That is the compressed version of the story. The longer version is a case study in how quickly a freshwater bivalve the size of a fingernail can alter the operating budget of a water utility.
What the mussel is, and what it does
The golden mussel is a small freshwater mollusk native to Asia. It reproduces rapidly, tolerates a wider range of temperatures and salinity than zebra and quagga mussels, and attaches itself with byssal threads to submerged hard surfaces…