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.

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

if a typical adult specimen.

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

Unless identified by a recognised expert, photographic evidence is required. A photo of the adductor scar is often needed. Note the shell's size. If it is an empty shell, it is advisable to retain this in case further checks are needed.

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

All year

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

Common.