When selecting shellfish, choose shells which are tightly closed and without any gaps or cracks - discard any shells that are open prior to cooking. When storing molluscs such as mussels, and live crustaceans, they should be covered with a damp cloth (or seaweed), with a lid kept on the box to avoid dehydration - this also helps to keep any excessive chill off the products. The ideal storage temperature is 6-8°C, but products should never be put directly in front of any fans blowing chilled air. 

Always pick up live crustaceans by the body, not the claws or tail, and treat

Oysters should be stored cup-side down to retain their fluid.