Invasion
Invasion Description
1st record: OR/Isthmus Slough, Coos Bay (1996, Suchanek et al. 1997); Tatoosh Island/WA/Pacific Ocean (Suchanek et al. 1997)
In this bioregion, Mytilus galloprovincialis and its hybrids have been absent (McDonald and Koehn 1988; McDonald et al. 1991) to rare in most studies. However, M. galloprovincialis has been planted in estuaries for mussel aquaculture (Brooks 1991, cited by Wonham et al. 2004) and can be expected to increase in abundance. Sampling in Humboldt Bay in 2002 indicated a greatly increased frequency of M. galloprovincialis and hybrids (~30 + 20%) 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).
Geographic Extent
Tatoosh Island/WA/Pacific Ocean (Suchanek et al. 1997); Newport/OR/Yaquina Bay (11% hybrids, Brooks 1991, cited by Wonham et al. 2004); OR/Isthmus Slough, Coos Bay (1996, Suchanek et al. 1997, 4 M. galloprovincialis, 2 M. trossulus); Crescent City/CA/Pacific Ocean (1990, ~4% M. galloprovincialis, 4% hybrids, Sarver and Foltz 1993; 1995, 6% M. galloprovincialis, Rawson et al. 1999); Eureka/CA/Humboldt Bay (1990, 1% hybrids, Sarver and Foltz 1993); Eureka/CA/Humboldt Bay (2002, ~30% M. galloprovincialis, 30% hybrids, Braby and Somero 2006); CA/Arcata Bay, Humboldt Bay (1995, ~1% M. galloprovincialis, 1% hybrids, Rawson et al. 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 | Hull Fouling |
| Alternate | Ballast Water |
| Alternate | Fisheries Accidental (not Oyster) |
Regional Impacts
| Economic Impact | Fisheries | |
| Mussel aquaculture was conducted in Humboldt Bay starting in 1992, but had ceased by 2008 (Conte 1992; California Department of Fish and Game 2010). | ||
| Ecological Impact | Competition | |
| In this bioregion, the native M. trossulus was once the sole mussel species. 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 less than 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). | ||