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Oithona davisae
Image courtesy of Jeffery R. Cordell, University of Washington
Oithona davisae
Taxonomic Group: Crustaceans-Copepods


Oithona davisae is a cyclopoid copepod. It was described from San Francisco, California in 1984, but is thought to be native to Japan and Korea. Its small size and the occurrence of similar species, has likely led to under-sampling and frequent mis-identification. Introduced populations are known from California, Washington, Spain, Ukraine, and Bulgaria. It is known from estuarine habitats and has been transported in ships’ ballast water. In recent years it has been the most abundant copepod in San Francisco Bay, being present in July thru November when temperatures are higher and river flows are lower. It is omnivorous and feeds on algae, ciliates, rotifers and copepod nauplii. Its presence may have an effect on the local food web, but specific impacts are not known.

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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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