The Common Mussel is a ‘bivalve’ mollusc which means that it has a soft body enclosed in two hinged shell, like the Grooved Razor Shell and the Common Oyster. It can be found all around the coasts of England on rocky shores attached to rock surfaces. It can also be found attached to piers and is often seen in large groups known as ‘mussel beds’. Large masses of mussel beds can be found in Morecombe Bay and in the estuaries of south-west England.
The Common Mussel has an almost triangular-shaped shell which is usually a purplish or a bluish colour. Sometimes the shell can be brown. The inside of the shell is pearly white with a blue coloured edge. The soft body inside is an orangy colour. The Common Mussel has a large muscular foot which is usually the only part of the body that can be seen outside the shell. The foot can produce a hard thread called the ‘byssus’ thread which the Common Mussel uses to attach itself onto hard surfaces.
Common Mussels lay their eggs directly into the sea where they develop and hatch. The newly hatched larvae become part of zooplankton for around four weeks before they settle on seaweed for a short while. They eventually detach themselves from the seaweed and drift in the water on ‘byssus’ threads for a short time before joining mussel beds to develop into adult Common Mussels.