California Floater Freshwater Mussel

California Floater Freshwater Mussel at the Malheur National Wildlife Refuge. Photo Credit: Al Smith


  • Species Common Name California Floater Freshwater Mussel
  • Species Scientific Name Anodonta californiensis
  • Federal Listing Status Species of Concern


Special needs

In Oregon, California floater freshwater mussels use speckled dace as a primary host (and likely many other fish species as well). These mussels occur in lakes, slow rivers, and some reservoirs with mud or sand substrates. They are sedentary filter feeders that consume plankton and other particulate matter suspended in the water column, thereby contributing to nutrient cycling. California floater freshwater mussels may prefer higher reaches of streams with high water quality.

Limiting factors

California floater freshwater mussels are threatened by loss of host fish and other anthropogenic impacts, including channel modifications, dredging and mining, contamination, sedimentation, nutrient enrichment, water withdrawal and diversion, poorly-managed livestock grazing in riparian areas, and the introduction of non-native fish and invertebrate species.

Conservation actions

Protect known populations of host fish. Maintain water quality.

Key reference or plan

The Xerces Society California Floater/Winged Floater Status Review