Invertebrates
Swan Mussel
Anodonta cygnea
On the silty bed of a clear lake, a swan mussel lies partly buried, a long furrow in the mud behind it showing where it has slowly moved.
Overview
The swan mussel, Anodonta cygnea, is a Least Concern freshwater mussel of lakes, ponds, canals, and slow rivers across Europe and northern Asia. Its large shell, fish-borne larvae, and role as a filter and host for the bitterling make it one of the key animals of still water.
A mussel with a fish hitchhiker’s tale
Because the swan mussel’s larvae need fish to carry them, the mussel is a sign that a lake still has a healthy fish population.
Status
Least Concern, though local populations have declined.
Swan Mussel: common questions
How does the swan mussel disperse?
Its larvae attach to the gills and fins of fish for a few weeks, which carry them to new places, before dropping off to settle on the bottom.
What is the link with the bitterling?
The European bitterling lays its eggs inside the gills of mussels such as the swan mussel.
How big is the swan mussel?
It has a large, thin shell, which can reach up to about 20 cm long.
Where is the swan mussel found?
It lives in lakes, ponds, canals, and slow rivers across much of Europe and northern Asia.