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Western Pearlshell
Margaritifera falcata
NatureServe conservation status
Global (G-rank): G3G4
State (S-rank): S1
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Species range
Western pearlshell are distributed throughout western North America with the densest populations occuring in the Pacific Northwest. In Utah, the species is distributed in the northern portion of the state.
Migration
Like all freshwater mussels, winged floaters rely on fish for their dispersal or migration.
Habitat
Western pearlshell tend to inhabit mid to high elevation cold water rivers and streams with cobble and boulders as the primary substrate.
Food habits
Western pearlshell are filter feeders. They siphon suspended particles from the water column which improves water quality, reduces turbidity, and helps control nutrient levels.
Ecology
Freshwater mussels are considered ecosystem indicators where their absence or presence can provide information about an ecosystem's overall health and condition.
Reproductive characteristics
Western pearlshell rely on fish to complete their reproductive cycle. These mussels release their larvae (glochidia) in sacks that attract fish to the mussel. As the fish attempts to feed on or attack the sack, the mussel releases its glochidia into the water which then encysts onto the fish's gills. Once the glochidia are developed, they will detach from the host fish as juvenile mussels and fall to the bottom of their habitat.
Threats or limiting factors
Threats to western pearlshell include: loss of host fish, urban development, channel modification, pollution, water management, improper grazing practices, habitat shifting and alteration, sedimentation, and increased temperatures.
