Invertebrates
Freshwater Pearl Mussel
Margaritifera margaritifera
Half buried in the gravel of a cold Scottish river, a freshwater pearl mussel filters the water, perhaps as old as the bridge that crosses the stream above it.
Overview
The freshwater pearl mussel, Margaritifera margaritifera, is an Endangered mussel of clean, cold, fast-flowing rivers in north-western Europe and north-eastern North America. Its century-long life, its larvae on salmon gills, and its rare pearls make it one of the most remarkable animals of European rivers.
A mussel that depends on a fish
Without young salmon and trout to carry its larvae, the pearl mussel cannot breed, so the health of the mussel is tied to the health of the river’s fish.
Status
Endangered, declining across its range.
Freshwater Pearl Mussel: common questions
How long does a freshwater pearl mussel live?
It can live for well over a hundred years, making it one of the longest-lived invertebrates known.
Why does the mussel need salmon and trout?
Its tiny larvae attach to the gills of young salmon and trout for several months, then drop off to settle in the river bed.
Why is it endangered?
It has declined drastically from pollution, siltation, river engineering, and past pearl fishing, and cannot survive in dirty water.
Where is the freshwater pearl mussel found?
It lives in clean, cold, fast-flowing rivers of north-western Europe and north-eastern North America.