Invasion
Invasion Description
1st Record: Eureka/CA/Humboldt Bay (1990, 1% hybrids, Sarver and Foltz 1993, molecular survey); Mendocino/CA/Pacific Ocean (1995, Rawson et al. 1999, molecular survey)
Geographic Extent
Eureka/CA/Humboldt Bay (1990, 1% hybrids, Sarver and Foltz 1993) ; Eureka/CA/Humboldt Bay (~30% M. galloprovincialis, 10% hybrids, in 2001-2004 1% hybrids, Braby and Somero 2006); CA/Arcata Bay, Humboldt Bay (1995, ~1% M. galloprovincialis, 1% hybrids, Rawson et al. 1999); CA/Humboldt Bay (88% of mussels selected for M. galloprovincialis morphology, Brooks 1991, cited by Wonham et al. 2004; aquaculture began in 1992, but ceased by 2008, Conte 1992, California Department of Fish and Game- Marine Region 2010)
Vectors
| Level | Vector |
|---|---|
| Alternate | Ballast Water |
| Alternate | Hull Fouling |
| Alternate | None |
| Alternate | Fisheries Intentional |
| Alternate | None |
Regional Impacts
| Economic Impact | Fisheries | |
| Mussel aquaculture has been conducted in Humboldt Bay, starting in 1992, but had ceased by 2008 (Conte 1992; California Department of Fish and Game 2010). | ||
| Ecological Impact | Competition | |
| Sampling in Humboldt Bay in 2002 indicated a greatly increased frequency of M. galloprovincialis and hybrids (~30 + 30%) over that seen in the 1990s (0-8%) (Braby and Somero 2006). However, in 2005-2007, the frequency of M. galloprovincialis and hybrids north of 39°N declined to about 5%. This change was attributed to lower temperatures, resulting from the Pacific Decadal Oscillation (Hilbish et al. 2010). | ||
| Ecological Impact | Hybridization | |
| In surveys done in the 1990s, the frequency of M. galloprovincialis X M. trossulus hybrids was low (1-8%) (Sarver and Foltz 1993; Rawson et al. 1999), but in samples taken in 2002, hybrids were more common (~20%) (Braby and Somero 2006). However, in 2005-2007, the frequency of hybrids north of 39°N declined to less than 5%. This change was attributed to lower temperatures, resulting from the Pacific Decadal Oscillation (Hilbish et al. 2010). | ||