Asian Clam (Corbicula fluminea)

The Asian Clam is a yellow-brown bivalve with a rounded or somewhat triangular shape, distinguished by prominent raised concentric rings. The colour can flake, leaving white spots, and the shells are slightly purple on the inside. They are a self-fertile species; a single individual can be enough to develop a new population. They reproduce at around 15°C from about three months of age. Larvae are released from spring to autumn. The Asian clam tolerates 2-34°C and can survive several weeks in water of 0°C. It also tolerates areas with hight nutrient loads or low oxygen levels.

This species has become a significant pest in many regions due to its rapid growth and high reproductive capacity. Large populations can disrupt ecosystem dynamics by increasing sedimentation and competing with native species for food. Additionally, they can reduce flow in certain drainage pipes by clogging up the narrow space. They can be spread as adults and larvae on boats, wetsuits, angling equipment, in ship’s ballast water and with overland boat transmissions. Now found in the River Trent system as well as in the lower Thames, Medway, Great Ouse systems and in one site near Cardiff, South Wales. 

• Avoid stepping into the water – this can stir up sediment, throwing up sediment DNA and any inhibitory molecules present. Sediment may clog the filter and prevent sufficient volumes of water being filtered.