Western pearlshell

Margaritifera falcata · Aquatic life

Underwater · Photo: Lee Cain / CC BY

NativeMollusk (mussel, clam, snail)

Also called Western pearlshell mussel, Margaritifera

How to identify Western pearlshell

Long, kidney or banana shaped shell up to about 5 inches
Dark brown to black outside
Purplish or pink pearly interior
Small peglike teeth near the hinge but no long lateral teeth

Similar species

Floaters (Anodonta) are thinner, lighter, rounder and have no hinge teeth.

Profile

Season	Present all year; releases larvae in spring and early summer.
Starts	Reproduces in spring
Depth	Buried in gravel and sand
How it spreads or reproduces	Larvae (glochidia) attach to the gills of trout and salmon
Habitat	Cold, clear streams and rivers with gravel and trout or salmon; sometimes in canals fed by those streams. In Wyoming, the Bear River.

Why it matters in a lake

Can live 100 years or more and has declined in many areas. Finding them in an irrigation canal or stream is a good sign of cold, clean water and healthy native fish.