The Clyde Sea Area has long been associated with shellfish fishing and has shared in the large expansion which has occurred during the past thirty-five years in the Scottish industry. Here, as elsewhere, the expansion has been helped by the establishment of processing facilities and in 1983 the landings of shellfish from the Clyde reached £4–5 million in value.

The sea bed and shores in the Clyde provide a wide range of habitats which is reflected in the commercially important species which are taken. They range from the fine mud in which Norway lobsters burrow, through sand in which cockles occur, and sandy gravel which is suitable for scallops and queens, to the hard ground inhabited by lobsters and the rocky shores on which periwinkles abound.

The most important shellfish in the Clyde, with annual landings valued at £3–75 million, is the Norway lobster, which is dealt with by Bailey et al. (1986). This contribution considers all the other species. The most valuable are scallops and queens, which now together exceed £400,000 p.a. in value. Periwinkles are gathered extensively on rocky shores. Squid are taken sporadically, by light trawlers and seine-netters, and occasionally, when they are especially abundant, form the basis of a directed fishery. Creel fishing for lobsters, edible crabs and velvet swimming crabs is less widespread than elsewhere round Scotland, but provides a useful income for a few boats. Mussels and cockles are gathered on a small scale, and cockle stocks in the Clyde proved especially valuable after English and Welsh stocks had been depleted by the severe winter of 1962–63. The only surviving fishery for the native oyster in Scotland is in the Clyde, in Loch Ryan, and attempts are being made to improve its production. Sea lochs in the Clyde offer conditions, particularly shelter, suitable for cultivating filterfeeding bivalve molluscs.