Mussel

Mussel, common name for any marine or freshwater bivalve mollusk closely related to oysters and scallops. Mussels are called filibranchiates, which means that the filaments, or branches, of their gills have interlocking bunches of hairlike cilia.

The common sea mussel, found attached to rocks on the shores of Europe and America, is widely used as food and fishing bait. Of the freshwater mussels, which are found in rivers and streams of North America, Europe, and Asia, about 60 commercially important species are found in the United States. Their shells are used in button making. The mussels themselves readily secrete pearls; most mussel pearls are of low quality and are used in making inexpensive jewelry. Studies of mussels show that they are severely affected by chemical pollutants. Some species, however, have become pests; since the mid-1980s the zebra mussel, native to the Caspian Sea, has invaded the Great Lakes and adjacent waterways in large numbers, threatening the region's environment and economy.

Scientific classification: Mussels belong to the class Bivalvia, phylum Mollusca. The common sea mussel is classified as Mytilus edulis. The zebra mussel is known as Dreissena polymorpha.