Invasion
Invasion Description
1st Records: Moss Landing/CA/Monterey Bay (1990, Sarver and Foltz 1993); near Moss Landing/CA/Salinas River Mouth (1990, Sarver and Foltz 1993)
Geographic Extent
CA/Elkhorn Slough (1992, Suchanek et al. 1997); Santa Cruz/CA/Monterey Bay (1995, Rawson et al. 1999); Moss Landing/CA/Monterey Bay (1990, Sarver and Foltz 1993; 2010, Saarman et al. 2015); near Moss Landing/CA/Salinas River Mouth (1990, Sarver and Foltz 1993); Monterey Marina/CA/Monterey Bay (1995, Rawson et al. 1999)
Vectors
| Level | Vector |
|---|---|
| Alternate | Hull Fouling |
| Alternate | Ballast Water |
Regional Impacts
| Ecological Impact | Hybridization | |
| In 1990-1994, 10-30% of mussels examined in Monterey Bay were hybrids (M. trossulus X M. galloprovincialis) outnumbering purebred M. trossulus (0-15%) (Sarver and Foltz 1993; Suchanek et al. 1997; Rawson et al. 1999). In 2005-2007, the frequency of hybrids was about 20-35%, but the abundance of purebred M. galloprovincialis had declined, due to changing oceanographic conditions, resulting in lower water temperatures, and a southward shift in the hybrid zone (Braby and Somero 2006; Hilbish et al. 2010). In 2010, at Moss Landing, introgression of M galloprovincialis into M. trossulus exceeded gene flow in the reverse direction (Saarman and Pgson 2015). | ||
| Ecological Impact | Competition | |
| In 1990-1994, purebred M. galloprovincialis comprised 45-95% of mussels in Monterey Bay samples, while purebred M. trossulus were 0-20%, and hybrids were 10-30% (Sarver and Foltz 1993; Suchanek et al. 1997; Rawson et al. 1999). However, by 2005-2007, purebred M. galloprovincialis declined to about 10-70% (Braby and Somero 2006; Hilbush et al. 2010), indicating that changing environmental conditions (declining water temperatures) due to climate cycles, were not favorable to M. galloprovincialis (Braby and Somero 2006; Hilbish et al. 2010). | ||