Invasion
Invasion Description
1st Record: Alameda/CA/San Francisco Bay (1907, Dall 1907, cited by Carlton 1979)
Geographic Extent
CA/Bodega Harbor (1968, Carlton 1979, possibly an escape or discard from nearby laboratory); CA/Tomales Bay (1930, failed, MacGinitie 1930, cited by Carlton 1979); CA/Bolinas Lagon "Bolinas Bay" (1920s, failed, Carlton 1979); Alameda/CA/San Francisco Bay (1907, Dall 1907, cited by Carlton 1979); Oakland/CA/Lake Merritt (Gilmore 1935, cited by Carlton 1979); Rodeo Marina/CA/San Pablo Bay (2004, Cohen et al. 2005); San Leandro Marina/CA/South San Francisco Bay (2004, Cohen et al. 2005); CA/Carquinez Straits (Cohen 2005); Palo Atlo mudflats/CA/South San Francisco Bay (1974, Nichols and Thompson 1985); Newark/CA/South San Francisco Bay (1975, Race 1982); San Mateo County, Menlo Park, Cooley`s Landing, S of S jetty/CA/South San Francisco Bay (CAS IZ 1035, California Academy of Sciences 2008); Solano County/CA/Carquinez Strait (CAS IZ 1314, California Academy of Sciences 2008); San Mateo County: Redwood City, Redwood City Harbor entrance channel/CA/South San Francisco Bay (California Academy of Sciences 2008); San Mateo County: Menlo Park/CA/Ravenswood Slough, south San francisco Bay (California Academy of Sciences 2008); NW of Davis Point/CA/ in mouth of Carquinez Strait (CAS IZ 11034, California Academy of Sciences 2008); Solano County/CA/Napa River, Mare Island Strait (CAS IZ 19449, California Academy of Sciences 2008); Contra Costa County: Richmond/CA/Hoffman Marsh, Central San Francisco Bay (CAS IZ 85280, California Academy of Sciences 2008); Santa Clara County/CA/off Charleston Slough (CAS IZ 122585, California Academy of Sciences 2008); San Mateo County: Foster City/CA/south San Francisco Bay (CAS IZ 122813, California Academy of Sciences 2008); Alameda County/CA/Mowry Slough, South San Francisco Bay (CAS IZ 122836, California Academy of Sciences 2008); Dumbarton Bridge/CA/South San Francisco Bay (CAS IZ 127975, California Academy of Sciences 2008); Santa Clara County/CA/Palo Alto Yacht Harbor (CAS IZ 127978, California Academy of Sciences 2008); Alameda County: Oakland, near Key Route pier/CA/Central San Francisco Bay (CAS IZ 128199, California Academy of Sciences 2008); CA/E of Carquinez Strait, W of Suisun Bay, Martinez Yacht Harbor (CAS IZ 128828, California Academy of Sciences 2008); Alameda County/CA/Newark Slough (CAS IZ 129768, California Academy of Sciences 2008); Marin County/CA/San Rafael Bay (CAS IZ 130799, California Academy of Sciences 2008); Selby, Contra Costa County/CA/Carquinez Strait (CAS IZ 137307, California Academy of Sciences 2008); Sonoma County/CA/Steamboat SloughSan Pablo Bay (CAS IZ 141546, California Academy of Sciences 2008); China Camp/CA/San Pablo Bay (2005, Robinson et al. 2011); Moss Landing. Monterey County/CA/Moss Landing Harbor (11-30-1971, CAS IZ 141661, California Academy of Sciences 2008)
Vectors
| Level | Vector |
|---|---|
| Probable | Oyster Accidental |
Regional Impacts
| Ecological Impact | Competition | |
| Tritia obsoleta has displaced the native snail Cerithidea californica in San Francisco Bay from tidal creeks. The native snails actively withdraw from T. obsoleta, and are mostly restricted to salt pans, which are frequently subject to high temperatures and desiccation (Race 1982). | ||
| Ecological Impact | Predation | |
| Tritia obsoleta actively feeds on the egg capsules of the native snail Cerithidea californica in San Francisco Bay (Race 1982) | ||
| Ecological Impact | Parasite/Predator Vector | |
| The introduction of T. obsoleta resulted in the transport of 5 digenetic trematode species to San Francisco Bay: Zoogonus lasius (as Z. rubellus); Lepocreadium setiferoides; Stephanostomum tenue; Himasthla quissetensis; Austrobilharzia variglandis. The first 3 of these species have fishes as final hosts; the last 2 have birds (shorebirds, gulls, cormorants, ducks) as final hosts (Blakeslee et al. 2012). The effect of these parasites on their final hosts is unknown. | ||
| Economic Impact | Health | |
| Tritia obsoleta is an intermediate host of the digenetic trematode (blood-fluke, schistosome) Austrobilharzia variglandis. The final host of the trematode is birds, but the cercaria frequently infect the skin of bathing humans, causing Swimmer's Itch (Grodhaus and Keh 1958). | ||