Western Pearlshell (Margaritifera falcata)

• Known across southern BC (reported as far east as Jaffray) and north to Babine Lake
• Up to 12.5 cm long
• Elongate, the top of the shell is curved and the bottom is concave.
• Shell is light brown (juveniles) to dark brown or black (adults)
• Nacre (inside of shell lining) is purple, salmon-coloured or pink
• Shell is thicker and less fragile than the Floater species
• Have “teeth” on the interior hinge (which create a strong connection between each valve). 
• Lifespan can be over 100 years old!

Live Western Pearlshell mussels, Shuswap River

“Winged Floater” (Anodonta nuttalliana*)

• Known from the lower mainland to the east Kootenays and north to Lac la Hache
• Up to 12.5 cm long
• Elliptical or ovate in shape.  The top margin is raised to form a “wing” (length to height ratio is <1.5)
• Shell is olive, yellow or reddish brown or black
• Nacre is white with sometimes a pink, blue or purplish tint
• Shell is thinner and more fragile than Western Ridged Mussel and the Western Pearlshell
• No hinge teeth

Winged Floater shell; Okanagan Lake

Note: Anodonta californiensis is not included here, as past records in B.C. are actually the A. nuttalliana species.

Note:  It is difficult to distinguish the following two species (A. kennerlyi; A. oregonensis) in the field, as distinguishing features often overlap;  taxonomic work is still needed to determine if they are genetically distinct.  The mussels in the following two photographs have not been confirmed.

“Western Floater” (Anodonta kennerlyi)

• Known throughout BC north to 56°N latitude
• Up to 12 centimetres long
• Elliptical or elongate in shape (length to height ratio is near or >2)
• Beak (raised, rounded area) does not project or barely projects above the hinge line
• Laterally inflated (fat) primarily along the posterior ridge (end farthest away

            from the beak) region.

• Shell is yellowish to brown, smooth and shiny
• Shell is thinner and more fragile than Western Ridged Mussel and Western Pearlshell
• No hinge teeth

Okanagan Lake (Anodonta sp.)

“Oregon Floater” (Anodonta oregonensis*)

• Across southern BC
• Up to 18 centimetres long
• Elliptical in shape (length to height ratio is near or >2)
• Shell is light to dark brown, smooth and shiny
• Beak does not project above the hinge line
• Laterally inflated (fat) primarily along the median region
• Shell is thinner and more fragile than Western Ridged Mussel and the Western Pearlshell
• No hinge teeth

Summit Lake (Anodonta sp.)

Western Ridged Mussel (Gonidea angulata*)

*this mussel is red-listed (endangered) in BC and should be disturbed as little as possible

• Known from the Okanagan Basin and 1 record from Kootenay River
• Up to 12.5 cm long
• Obovate to trapezoidal in shape
• Distinguishing feature is the prominent ridge that runs along top of the shell
• Shell is dark brown to black
• Nacre is white or salmon coloured in the middle and pale blue near the margin
• Shell is thicker than the Floater species
• Hinge teeth small and compressed; they are sometimes hard to distinguish (right valve has 1 small tooth and left valve has either 1 or no tooth)

Live Western Ridged Mussels, Vaseux Lake

Yukon Floater (Anodonta beringiana*)

• Possibly occurs in the Yukon drainage in northwest BC (there are no collection records for BC)
• Up to 21 cm long
• Shape is elliptical or elongate
• Shell is olive green in juveniles to nearly black in mature individuals
• Nacre is lead-colour to dull blue
• The shell is thin, but relatively strong
• No hinge teeth

Yukon Floater (photo from: Freshwater mussels of the Pacific Northwest handbook)