Anodonta sp.

• Widely distributed from Baja California (Mexico) to Alaska

• Generally west of Rocky Mountains

• Great uncertainty about species identification

• 2 main clades (groups) of species are distinguished by the shape of the shell



Identification Tips:

• To 20 cm length, but 10-15 cm common
• Shells are thin and fragile
• No tooth on inside of shell at hinge
• Usually brownish in colour in Fraser Valley
• White fleshy nacre visible on shell margin when open
• 'Wing' at hinge may be present

Clade 1: Ratio of length to height of shell is less than 1.5
Clade 2: Ratio of length to height of shell is greater than 1.5

Life History:

• Rapid growing
• Sexually mature in 4 to 5 years
• Short-lived (10-15 years) compared to most mussels
• Found in high densities in mud or sand bottoms of lakes, ponds and slow moving streams
• Can occur in protected sites within fast rivers

Very SensitiveSomewhat SensitiveFacultativeSomewhat TolerantVery Tolerant

Primary Information Source:
Voshell, J. Reese. 2002. A Guide to Common Freshwater Invertebrates of North America. McDonald and Woodward Publishing Company. Blacksburg, Virginia.

Mussel Survey, Cascade Bay, Harrison Lake

Mussel Survey, Cascade Bay, Harrison LakeWe measure shell dimensions to identify closely related species. All are returned to the lake bed- right side up, of course!

Posted by Pearson Ecological on Friday, September 15, 2017