Scallops

Scallops can rapidly propel themselves through the water by shutting and opening their shells' valves. These sudden actions expel water, firing the scallops backwards hinge foremost. Their swimming is very distinctive, in a series of jerky movements.

Scallops have unusual life stages depending on the species, they often change their sex throughout their life; and in the earlier stages can be sessile attaching themselves with byssal threads.

As with all all bivalves, scallops have two shells (valves). The upper valve is flat the bottom convex. They lie on the sea bottom on their convex side.

When at rest, both the valves part exposing the mantle. On the edge of the mantle are the sensory organs, eyes and tentacles. The eyes of which there can be many, are well developed, each having a retina, lens and optic nerve. The tiny tentacles sense water pressure changes and scents.

There are a number of species found in Cornwall however it is not always easy to identify the species from one another. Often the ears are important in determining species, however these are not often present on shells found thrown up on the beach, as they are the first part of the shell to be eroded.

Scallop Species Found on Cornish Shores

      Great Scallop Pecten maximus

      Variegated Scallop Chlamys varie

       Queen Scallop Aequipecten opercularis

Great Scallop Pecten maximus

Great scallops can be large shells growing up to 6 inches across. The left valve is flat while the right is convex. The latter are commonly sold as ash trays. The heavily ridged shell comes in reddish browns, the convex valve is often lighter in colour and can even be white. This mollusc is commercially fished which has led to a decline in their number. A deep water species, but the shells are commonly thrown ashore.

Queen Scallop Aequipecten opercularis

The Queen Scallop is difficult to tell apart from Pecten maximus, if only one shell is found. However if both shells are found together it can be easily identified as both it shells are convex, the left valve being more so. It is a deep water species which is commercially fished, but it can be found on the shore. The shell reaches up to 3 and a half inches. It is very variable in colour, white, yellow, red, brown or even striped.

Variegated Scallop Chlamys varie

A relatively small scallop reaching over 2 inches. The shell colour is highly variable including pink, yellow, white, purple, red, brown or orange. The ears are strongly assymetrical with one ear being noticeably large. They are a deep sea species but can be found on the shore. They may be found attached by byssal threads.