E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Anodonta kennerlyi Lea, 1860
Western Floater
Family: Unionidae
Species account authors: Ethan Jay Nedeau, Allan K. Smith, Jen Stone, and Sarina Jepsen.
Extracted from Freshwater Mussels of the Pacific Northwest, 2nd Edition (2009)
© Xerces Society for Invertebrate Conservation.

© Ian Gardiner  Email the photographer   (Photo ID #78246)

E-Fauna BC Static Map
Distribution of Anodonta kennerlyi in British Columbia
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Species Information

Size: Adult size from 4.75 to 7.25 inches.

Shape: Elliptical; L:H ratio close to, or exceeding, 2.0. Dorsal posterior mar­gin may be compressed and formed into slight wing, but this trait is variable. Valves laterally inflated, thin, and fragile.

Beaks: Low; rarely project above the hinge line.

Periostracum: Yellowish, yellowish-brown, brown, or black. Some specimens may have a tinge of green. Periostracum is usually shiny, and growth lines are usually evident.

Hinge Teeth: None.

Nacre: White or bluish-white, sometimes pinkish toward the central portion of the nacre and iridescent toward the posterior end.

For a discussion on Anodonta taxomony, please refer to the original publication, The Freshwater Mussels of the Pacific Northwest.


Like other Anodonta, this is thought to be a fast-growing species that reaches sexual maturity in four to five years and lives only ten to 15 years. Host fish are unknown. Like other Anodonta, this species is likely a likely long-term brooder that breeds in the summer and spawns in the fall or spring. In lake populations of A. kennerlyi, gravid females were observed from late summer to the following spring, and glochidia were found on fish from fall through the spring but peaked in the spring. Very little is known about host fish relationships. In lakes on Vancouver Island, British Columbia, glochidia of A. kennerlyi were found on all fish species examined (four species) but prickly sculpin and three-spine stickleback were more important hosts than the two trout species (Dolly Varden trout and cutthroat trout), possibly because the sculpin and stickleback were more prevalent in areas of the lakes were mussels were concentrated.


A. oregonensis and A. kennerly inhabit low gradient rivers, lakes, and reservoirs. They often share habitat with A. californiensis where their ranges overlap.


Global Distribution

The geographic range of this clade is in question because of the taxonomic uncertainty that has plagued these “species.” A. oregonensis were confused with A. beringiana in the northern part of their range and confused with A. californiensis in the southern part of their range. Currently, A. oregonensis and A. kennerlyiare thought to belong to a lineage that is distinct from the other western Anodonta. A. oregonensis is thought to range as far north as southern British Columbia. A. kennerlyi has been considered a more northern species found in watersheds of Oregon, Washington, Alaska, British Columbia, Alberta, and northern Saskatchewan. It is found in the Peace River in British Columbia, which is part of the Arctic watershed, and also on coastal islands in British Columbia.
Distribution in British Columbia

In BC, this species is known throughout BC north to 56°N latitude (Gelling 2008).


Conservation Concerns

This clade is likely affected by the same factors that affect other western Anodonta, including water diversion, dams, loss of host fish species, pollution, and invasive species. Since A. kennerlyi is distributed in less-disturbed northern areas, it has probably not experienced the full range of stressors experienced by more southern and coastal Anodonta. Thorough surveys are needed to determine the current distribution of this clade, although the authors are not aware of any evidence that suggests this clade is in decline.


The Unionidae are distributed throughout the world, but are most diverse in eastern and central North America, and in China and Southeast Asia.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
NativeS5YellowNot Listed
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Range and Status Information Links

Additional Photo Sources

General References

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2021-05-14 7:03:41 PM]
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