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Craspedacusta sowerbii
Image courtesy of OpenCage (CC-BY-SA-2.5 license) via Wikimedia Commons
Craspedacusta sowerbii
Taxonomic Group: Cnidarians-Hydrozoans


Craspedacusta sowerbii is a freshwater hydrozoan with a conspicuous medusa stage. It is believed to be native to the Yangtze Valley, China, but the medusa was first described from a water-lily tank in Regent's Park, London in 1880. Since then, it has been introduced to every continent except Antarctica, presumably with shipments of aquatic plants. In North America, it was first recorded in 1885 in Pennsylvania, but has since been reported from 150+ localities, with more occurrences in the east (New Brunswick, Quebec, and Ontario to Florida) than in the west. It occurs frequently in aquaria, but also in artificial and natural ponds, reservoirs, backwaters and pools of rivers. The hydroids grow on rocks, sticks and vegetation. There are no reported ecological and economic impacts of C. sowerbii.

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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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