NEMESIS Bioregion Distribution:


Native  Introduced  Cryptogenic  Failed


First Non-native North American Marine/Estuarine Record: 1984
First Non-native West Coast Marine/Estuarine Record: 1984



General Invasion History:

Ascidia zara is native to the Northwest Pacific, ranging from Hokkaido, Japan (Nishikawa 1991) to the southern tip of Korea (Cheju Island; Rho et al. 2000). On the Pacific coast of North America, it has been collected in California and Bahia San Quintin, Mexico. It was first recognized in southern California in 1996; however, a preserved specimen from Los Angeles-Long Beach Harbor in 1984 was identified as A. zara (Lambert and Lambert 1998). This suggests that A. zara arrived prior to 1996, but went unnoticed because of its similarity to the native tunicate A. ceratodes

North American Invasion History:

Invasion History on the West Coast:

Ascidia zara was first recognized in southern California in 1996; however, a preserved specimen from Los Angeles-Long Beach Harbor in 1984 was identified as A. zara (Lambert and Lambert 1998). This suggests that A. zara arrived prior to 1996, but went unnoticed because of its similarity to the native tunicate A. ceratodes. It was collected in San Francisco Bay in 2000 (Ruiz et al. unpublished) and Elkhorn Slough and Bodega Harbor in 2001 and 2003 (Fairey et al. 2002; de Rivera et al. 2005). It is now widespread in San Francisco Bay (Cohen et al. 2005; Ruiz et al., unpublished data). In sampling throughout Southern California, Ascidia zara was abundant and widespread from 1995 to 2000 (Lambert and Lambert 1998; Lambert and Lambert 2003), but in 2011, was scarce. The native Ascidia ceratodes, which had become rare, was again common (Gretchen Lambert 2012, personal communication).

Invasion History elsewhere in the World:

In 2005, Ascidia zara was collected in Bahia San Quintin, Mexico (Rodriguez and Ibarra-Obando 2008), but may have been overlooked in previous surveys there.