Zebra Mussel
Dreissena polymorpha (Pallas, 1771)
Family Dreissenidae (False Mussels)
The Zebra Mussel is native to the Black and Caspian seas and was introduced to the Great Lakes in 1985. It has since spread throughout the Mississippi River and other major freshwater drainages in the United States. The Zebra Mussel, like other “mussels,” attaches to hard surfaces using byssus threads secreted by a gland in the foot. As a consequence, it has become a major pest species in the US, clogging power plant intake pipes and attaching to boat hulls, docks, and buoys. It also is a serious threat to freshwater pearl mussels, with which it competes for food and space. It can also smother a pearl mussel by coating its shell (like this Fatmucket [Lampsilis siliquoidea (Barnes, 1823)] from Ohio), interfering with its respiration and ability to burrow in the sand. False mussels differ from true mussels (family Mytilidae) in several key characteristics in the hinge, siphons, gills, and digestive system.
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