Examples include periwinkles, conches, and whelks. Shellfish include mussels, cockles, periwinkles, clams, and oysters. Clams, periwinkles, crabs, shrimp, starfish and sea urchins are found on most beaches. It feeds on periwinkles, other urchins and coralline algae. Wales is known for its shellfish, including cockles, limpet, mussels and periwinkles. Crabs, river snakes, otters, water birds and periwinkles can also be seen. Oysters were eaten on both shores, as were mussels and periwinkles. St. Fishmonger allegedly caused crabs and periwinkles to fall from the sky. Periwinkles are graded by number of snails per kilogram. Washed up on the beach, you can also find cockles, mussels, periwinkles and tellins. The island's only permanent macro-organism inhabitants are common periwinkles and other marine molluscs. Animals include the Snakelocks anemone "Anemonia viridis", the Spotted goby "Gobius ruthensparri", Periwinkles "Littorina" spp. Like the genus "Vinca", they are known commonly as periwinkles. Sea life includes plenty of dolphins, sea horses, periwinkles, and numerous species of fish. Some types of periwinkles, Neritidae and detritus feeding Isopoda commonly inhabit the lower supralittoral.