Invasion
Invasion Description
1st Record: San Rafael/CA/San Pablo Bay (1987, McDonald and Koehn 1988; McDonald et al. 1991).
The actual invasion date is unknown. This species was first detected in molecular surveys, which began in 1985 (McDonald et al. 1991). This bay is in a hybrid zone for Mytilus galloprovincialis and M. trossulus, so the two species and their hybrids fluctuate with changing environmental conditions (Braby and Somero 2006). In 2010, populations in Berkeley and Oakland were 80 and 100% M. galloprovincialis, while percentages in San Rafael and Carquinez Straits were around 2-5% (Saarman and Poggson 2015).
Geographic Extent
San Rafael/CA/San Pablo Bay (1987, McDonald and Koehn 1988; McDonald et al. 1991); North Beach/CA/San Francisco Bay (37 29N, 122 06W, 1992, Suchanek et al. 1997); Sausalito/CA/Golden Gate (1990, Sarver and Foltz 1993); Benicia/CA/Carquinez Straits (1990, Sarver and Foltz 1993; 2010, Saarman and Poggson 2015); Berkeley/CA/San Francisco Bay (Sarver and Foltz 1993); San Leandro/CA/South San Francisco Bay (2004, Braby and Somero 2006); Palo Alto Yacht Club/CA/South San Francisco bay (1992, Suchanek et al. 1997);
Vectors
| Level | Vector |
|---|---|
| Alternate | Ballast Water |
| Alternate | Hull Fouling |
Regional Impacts
| Ecological Impact | Hybridization | |
| Mytilus galloprovincialis was first detected in molecular surveys, begun in 1985 (McDonald et al. 1991). This bioregion is a hybrid zone for Mytilus galloprovincialis and M. trossulus. Since molecular studies began in the late 1980s and early 1990s, both species and hybrids have coexisted but have varied in abundance with changes and gradients of salinity and temperature. At different sites in the Bay, the frequency of M. galloprovincialis X M. trossulus hybrids has varied from ~0-40% (Sarver and Foltz 1993; Suchanek et al. 1997; Rawson et al. 1999; Braby and Somero 2006), apparently changing both along environmental gradients, and fluctuating with cyclic changes in temperature and river flow. | ||
| Ecological Impact | Competition | |
| Mytilus galloprovincialis was first detected in molecular surveys, begun in 1985 (McDonald et al. 1991). This bioregion is a hybrid zone for Mytilus galloprovincialis and M. trossulus. Since molecular studies began in the late 1980s and early 1990s, both species and hybrids have coexisted but have varied in abundance with changes and gradients of salinity and temperature with M. galloprovincialis prevailing at higher salinities and higher temperatures, while M. trossulus predominated at lower salinities, and at lower temperatures. These interactions were complex, so that M. trossulus outnumbered M. galloprovincialis at low salinity sites in San Francisco Bay, even though these sites had higher temperatures (Braby and Somero 2006). | ||