Examples of bivalves are clams, scallops, mussels, and oysters. Bivalves include clams, oysters, cockles, mussels, scallops, and numerous other families. Giant clams, green mussels and oysters support edible shellfishery. Molluscs include sea hares, bay mussels, and oysters. Shellfish, including crabs, prawns, tiger prawns, lobster, squid, and mussels, are commonly eaten. The bacterial mats provide nourishment for mussels, clams, limpets and sea snails. The class has 30,000 species, including scallops, clams, oysters and mussels. Seafood such as oysters, mussels and crayfish are not uncommon. Not all mussels and oysters produce pearls. Tide pools provide a home for hardy organisms such as starfish, mussels and clams. Wales is known for its shellfish, including cockles, limpet, mussels and periwinkles. Coupeville's Penn Cove Mussel Farm exports large quantities of its highly renowned Penn Cove Mussels. Common ingredients include onions, garlic, Korean zucchini, carrots, cabbages, squid, mussels, and pork. Silver carp feed on the plankton necessary for larval fish and native mussels. Octopus, sea urchins and mussels feature heavily.