Each year about £250,000 worth of periwinkles are picked on our shores. This makes them far and away the most valuable molluscs in our fishing industry. What is more, the value might be doubled if the catch were to be handled carefully. The fact is that, although they appear very tough, the periwinkle are in some ways delicate animals and rough treatment kills many of them. An important fact in the periwinkle industry is that the resource is a natural one which costs little to exploit. No equipment is required to harvest them because they are simply picked by hand when the tide is out.