Between 2007 and 2011, Scottish scallop fishermen harvested more than 78,000 tonnes and earned nearly £150 million.
The boats drag large metal rakes across the seabed to scoop the scallops out of the sand. Some 98% of scallops are harvested this way, with the rest individually plucked by divers. More than 80% are exported to Europe. Scallops are large fan-shaped shellfish found all around our shores, out to depths of 180 metres, and can grow up to 17cm wide.
They are unusual among shellfish because they can swim short distances by squirting out jets of water.
They have 100 simple eyes and are hermaphrodites, using both male and female sexual organs.