Duck Mussel - Anodonta anatina


One of the largest of our freshwater bivalves, typically 75mm but up to 120mm in length. It has a thin shell and is generally slim when closed. Brown and yellow in colour. The hinge margin is notably angled from the mid-axis.

Similar Species

The Swan Mussel, Anadonta cygnea, is larger and the hinge margin is parallel to the mid-axis.

The two can also be distinguished by looking at the posterior (pointed end) adductor muscle scar. In the Swan Mussel, the scar is joined to the pedal retractor scar by a narrow isthmus, whereas in the Duck Mussel these two scars are completely merged.


Identification difficulty
ID guidance
  • large: 75-120mm
  • hinge margin angled from the mid-axis
  • differential shell thickening on posterior, giving crimped appearance at posterior

Diverse. Small streams to large rivers, lakes, ponds and canals.

When to see it

All year

UK Status

Common and widespread in England, less so in Wales and Scotland.

VC55 Status


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Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map