Oysters are bivalve molluscs prized for their delicate fleshy interior. The Pacific, Japanese or rock oyster Crassostrea gigas has largely taken over from the British native oyster, Ostrea edulis because it is easier to farm, grows faster and may be harvested all year round. Port Navas developed as a port for the local granite industry but today is home to Duchy Oysters and the oyster fishery on the Fal and Helford is undergoing a twenty-first century revival.