About the Data

Species records include data on invasions history, distribution, ecology, impact, and more. These data were gathered from published literature and targeted surveys. All records have undergone expert review, unless otherwise noted.

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Species Profiles

NEMESIS includes detailed information on about 500 species of marine and estuarine of invertebrates and algae introduced to the United States. Each record contains information on taxonomy, distribution, ecology, and impacts, as well as references.

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Daily Invader

Ascidia sp. A

Ascidia sp. A

Ascidia sp. A does not match any previously described species. It is long and flat with a thin and translucent tunic; the oral siphon is long and the atrial siphon is shorter and emerges from the posterior half of body. It was first discovered in 1983 in San Diego and San Francisco Bays in California and subsequently became common in fouling communities along the California coast from San Diego to San Francisco Bay. However, in 2011, this species was absent from a number of locations sampled throughout California. Its establishment and impacts are unknown on the West Coast.

Daily Invader for 2024-02-21

Image Credit Nadia Bonnet, Universidade Federal do Paraná, Brazil. Image is of a general Ascidiidae species and is adapted from Kott (1985).
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