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Geukensia demissa
Image courtesy of Melissa Frey, Royal BC Museum
Geukensia demissa
Taxonomic Group: Mollusks-Bivalves


Geukensia demissa, commonly known as the Atlantic Ribbed Mussel, ranges naturally from the southern Gulf of St. Lawrence to Palm Beach, Florida. It was first collected on the West Coast of North America in San Francisco Bay, California in 1894, where it was introduced with Eastern Oyster imports. Its introduced range now spans from Mexico to Tomales Bay, California. An introduced population in Venezuela requires verification as G. demissa and not the formerly conspecific southern species G. granossisima. This species is most commonly found in salt-marsh habitats, but can also be found on rocks, wood and other hard substrates. It has had negative impacts, including possible structural effects on marsh channels and dikes, in parts of its introduced range.

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Fofonoff PW, Ruiz GM, Steves B, Simkanin C, & Carlton JT (2018)
National Exotic Marine and Estuarine Species Information System.
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Marine Invasions Lab
Smithsonian Environmental Research Center

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