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

Pisidium compressum Prime, 1852
Ridgebeak Peaclam
Family: Sphaeriidae
Photo of species

© Ian Gardiner  Email the photographer   (Photo ID #112719)

E-Fauna BC Static Map
Distribution of Pisidium compressum in British Columbia
Details about map content are available here.


Pisidium compressum is widespread in Canada and Alaska south of the tree line. It is found throughout the United States and extends into Mexico (Clarke, 1981). Next to P. casertanum, it is the most common sphaeriid in North America (Mackie, 2007). It is widespread in British Columbia.

This species is most common in lotic environments (creeks and rivers), although it is also common in shallow areas of small and large lakes. It inhabits only perennial water bodies, usually with some current or wave action (Mackie, 2007). It has a preference for sandy bottoms with vegetation, and shallow water (Herrington, 1962), though Clarke (1973) found this species associated with all types of bottom deposit, with mud the most frequent.

Note Author: Ian Gardiner

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

Species References

Clarke, A.H. 1973. The freshwater molluscs of the Canadian Interior Basin. Malacologia 13 (1-2): 1-509.

Clarke, A.H. 1981. The freshwater molluscs of Canada. National Museum of Natural Sciences, National Museums of Canada, Ottawa, Ontario: 446pp.

Herrington, H.B. 1962. A revision of the Sphaeriidae of North America (Mollusca: Pelecypoda). Miscellaneous Publications, Museum of Zoology, University of Michigan, No. 118: 74pp, 7 plates.

Mackie, G.L. 2007. Biology of freshwater corbiculid and sphaeriid clams of North America. Ohio Biological Survey Bulletin New Series. Vol XV No. 3: ix + 436pp.

General References

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. 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: 2024-06-18 5:54:17 PM]
Disclaimer: The information contained in an E-Fauna BC atlas pages is derived from expert sources as cited (with permission) in each section. This information is scientifically based.  E-Fauna BC also acts as a portal to other sites via deep links.  As always, users should refer to the original sources for complete information.  E-Fauna BC is not responsible for the accuracy or completeness of the original information.

© E-Fauna BC 2021: An initiative of the Spatial Data Lab, Department of Geography, UBC