Golden Mussels
Credit: California Department of Fish and Wildlife
What are they?
Golden mussels (Limnoperna fortunei) are invasive freshwater mussels that recently arrived in North America. First detected in California in October 2024, these mussels feature shells that range from rich gold to dark brown and grow up to 1 ¾ inches long.
Like zebra and quagga mussels, golden mussels use strong byssal threads to anchor themselves to almost any underwater surface. They begin life as microscopic larvae (veligers), which allows them to hide in standing water and be transported on boat hulls, trailers, and fishing gear.
Credit: California Department of Fish and Wildlife
Credit: California Department of Fish and Wildlife
Are they here yet?
Not yet. Currently, California is the only state with confirmed populations. They have been found in the Sacramento-San Joaquin Delta and as far south as Riverside County.
While they haven’t reached Washington, these mussels are hardy travelers. The California Department of Fish and Wildlife is actively monitoring their spread, and we are keeping a close watch on incoming watercraft to ensure they don’t make their way north to our local lakes.
Why should you care?
Golden mussels are filter feeders that can significantly alter water quality and harm our native aquatic species. They also pose a unique threat because they can survive in warmer water with lower calcium levels, and even brackish (slightly salty) conditions.
If they reach Lake Whatcom or Lake Samish, they could:
- Form dense colonies that clog drinking water intakes and pipes.
- Affect water quality, creating unpleasant tastes and odors in our local supply.
- Damage your property by attaching to boat motors, docks, and swimming areas.
- Outcompete native species, permanently altering our local ecosystem.
Because the full extent of their spread is still being determined, your help is vital. Remember to CLEAN, DRAIN, and DRY all equipment every time you leave the water.
Resources
Report sightings by calling 1-877-9-INFEST or report online.
