Golden mussel (Limnoperna fortunei) Aquatic Invasive Species: Risk Screening Summary

On November 6, 2024, California Department of Fish and Wildlife announced the discovery of golden mussels (Limnoperna fortune) in the Port of Stockton by California Department of Water resources staff while conducting routine operations. This is a rapidly developing situation and reports continue to come in and are being followed up on. These mussels were likely introduced to California by a ship traveling from an international port. This discovery is the first known occurrence of golden mussels in North America. Delineation is ongoing, with 30 known locations as of December 16, 2024 (Figure 1). Additional validated sightings will be made available on a map at the following website: Golden Mussel Sightings in California.

Classification under Washington Administrative Code (WAC) Chapter 220-640

L. fortunei is not listed as a Prohibited or Regulated type A or B aquatic invasive species under Washington Administrative Code (WAC) Chapter 220-640. Therefore, L. fortunei is classified as a Regulated Type C species under WAC 220-640-080. Per Revised Code of Washington (RCW) 77.135, Regulated Type C species may not be introduced on or into a water body or property without department authorization, a permit, or as otherwise provided by rule.

Distribution in Washington

As of 12/16/2024, there have been no recorded detections of L. fortunei in Washington.