Invasion
Invasion Description
1st record: CA/San Francisco Bay (1950s, Hedgepeth 1962, cited by Carlton 1979)
Geographic Extent
CA/San Francisco Bay (1950s, Hedgepeth 1962, cited by Carlton 1979); CA/South San Francisco Bay (Hopkins 1968, cited by Cohen and Carlton 1995); CA/San Pablo Bay (Hopkins 1968, cited by Cohen and Carlton 1995; Peterson and Vayssieres 2010, present in dry years); China Camp/CA/San Pablo Bay (2005, Robinson et al. 2011); Martinez/CA/Carquinez Straits (Hopkins 1968, cited by Cohen and Carlton 1995); Sierra Point Marina/CA/South San Francisco Bay (2004, Cohen et al. 2005); Pier 39, San Francisco/CA/San Francisco Bay (2004, Cohen et al. 2005); Richmond Marina/CA/South San Francisco Bay (2004, Cohen et al. 2005; 2010, Marrafini et al. 2017); San Francisco Marina/CA/South San Francisco Bay (2004, Cohen et al. 2005; 2010, Marrafini et al. 2017); San Leandro Marina/CA/South San Francisco Bay (2004, Cohen et al. 2005; 2010, Marrafini et al. 2017); Coast Guard Island, Oakland/CA/Oakland estuary (2004, Cohen et al. 2005); Presidio Yacht Club, San Francisco/CA/Golden Gate (2004, Cohen et al. 2005); Richmond Marina/CA/San Francisco Bay (2004, Cohen et al. 2005); Pete's Harbor /CA/South San Francisco Bay (2004, Cohen et al. 2005); Coyote Point Marina/CA/South San Francisco Bay (2004, Cohen et al. 2005); Brisbane/CA/Brisbane Lagoon, South San Francisco Bay (2004, Cohen et al. 2005); Fruitvale Bridge, Alameda/CA/Oakland estuary (2004, Cohen et al. 2005); CA/South Francisco Bay (2012-2013, Jimenez et al. 2017, mostly on hard and soft substrates)
Vectors
| Level | Vector |
|---|---|
| Alternate | Hull Fouling |
| Alternate | Oyster Accidental |
Regional Impacts
| Ecological Impact | Competition | |
| Extremely dense populations have been noted in San Francisco Bay, clogging bottom trawls (Ganssle 1968, cited by Cohen and Carlton 1995). Communities of Molgula manhattensis and Pinuauy crocea occupied considerable space on fouling plates in the winter of 1980/81, but were displaced by heavy settlement of mussels in Spring (Okamura 1986). When another tunicate, Ciona intestinalis was removed from experimental trials, M. manhattensis covered up to 92% of fouling plates (Blum et al. 2007). | ||