NEMESIS Bioregion Distribution:


Native  Introduced  Cryptogenic  Failed


First Non-native North American Marine/Estuarine Record: 1983
First Non-native West Coast Marine/Estuarine Record: 1983



General Invasion History:

Ascidia sp. A was discovered in 1983 in San Diego and San Francisco Bay. Since its discovery it has become established in other areas in Califonia including Alamitos Bay, King Harbor and Marina Del Ray (Santa Monica Bay) and Port Hueneme (Lambert and Lambert 1998; Lambert and Lambert 2003). In 2012, Ascidia sp. A was absent in samples taken from bays and harbors along the California coast and 'It may no longer be present' (Gretchen Lambert 2012, personal communication). Further sampling will be needed to confirm whether Ascidia sp. A is extinct in West Coast waters.

North American Invasion History:

Invasion History on the West Coast:

Ascidia sp. A is an unidentified solitary tunicate that appears to be an invader of the California coast. It was first collected in San Diego Bay and San Francisco Bay in 1983 and subsequently established there and in Alamitos Bay, King Harbor and Marina Del Ray (Santa Monica Bay) and Port Hueneme (Cohen and Carlton 1995; Lambert and Lambert 1998; Lambert and Lambert 2003). In 2012, Ascidia sp. A was absent in samples taken from bays and harbors along the California coast and 'It may no longer be present' (Gretchen Lambert 2012, personal communication).