Invasion
Invasion Description
1st Records: San Diego/CA/San Diego Bay (1987, McDonald and Koehn 1988; McDonald et al. 1991); Los Angeles/CA/Los Angeles Harbor (McDonald and Koehn 1988; McDonald et al. 1991).
The actual invasion date is unknown, but a great increase in abundance of 'blue mussels' in the 1940s (Coe 1946. cited by Carlton 1979), may mark its invasion and replacement of M. trossulus in southern California. This species was first detected in molecular surveys, begun in 1985 (McDonald and Koehn 1988; McDonald et al. 1991). Mytilus galloprovincialis has largely replaced the native M. trossulus in this region (Geller et al. 1994; Geller 1999). Purebred M. trossulus and hybrids with M. trossulus were rare in this bioregion (McDonald et al. 1991; Sarver and Foltz 1993; Suchanek et al. 1997; Rawson et al. 1999; Braby and Somero 2006).
Geographic Extent
Baja California/Mexico/Mina del Fraie (1995, Curiel-Ramirez and Caceres-Martinez 2004); Baja Caliornia/Mexico/Bahia de Todos Santos (1995, Curiel-Ramirez and Caceres-Martinez 2004); San Diego/CA/San Diego Bay (1987, McDonald and Koehn 1988; McDonald et al. 1991); San Diego/CA/San Diego Bay (1992; Geller et al. 1994; Suchanek et al. 1997); Chula Vista Boat Ramp, San Diego/CA/San Diego Bay (2000, Cohen et al. 2002); Seaforth Marina, San Diego/CA/Mission Bay (2000, Cohen et al. 2002); Scripps Pier, La Jolla/CA/Pacfiic Ocean (1992, Suchanek et al. 1997); San Diego/CA/San Dieguito Lagoon (2000, Cohen et al. 2002); Snug Harbor Marina, San Diego County/CA/Aqua Hedionda Lagoon (2000, Cohen et al. 2002; ongoing aquaculture; Conte 1992; California Department of Fish and Game 2010); Newport Beach/CA/Newport Bay (1990, Sarver and Foltz 1993); Long Beach Yacht Club/CA/Alamitos Bay (2000, Cohen et al. 2002); Long Beach/CA/Colorado Lagoon (2000, Cohen et al. 2002); Pilot's Dock F, Long Beach/CA/Long Beach Harbor (2000, Cohen et al. 2002); Los Angeles/CA/Los Angeles Harbor (McDonald and Koehn 1988; McDonald et al. 1991); Newmarks Yacht Harbor, Watchorn Basin/CA/Los Angeles Harbor (2000, Cohen et al. 2002), Cabrillo Boat Ramp, Los Angeles/CA/Los Angeles Harbor (2000, Cohen et al. 2002); Los Angeles/CA/Rainbow Lagoon (2000, Cohen et al. 2002); Redondo Beach/CA/King Harbor (2000, Cohen et al. 2002); Venice/CA/Marina del Rey (2000, Cohen et al. 2002); Oxnard/CA/Port Hueneme (2000, Cohen et al. 2002); Jack's Landing, Oxnard/CA/Channel Islands Harbor (2000, Cohen et al. 2002); Anacapa Island Marina, Oxnard/CA/Channel Islands Harbor (2000, Cohen et al. 2002); Ventura/CA/Pacific Ocean (1990, Sarver and Foltz 1993); Santa Barbara/CA/Pacific Ocean (1990, Sarver and Foltz 1993, ongoing aquaculture; Conte 1992; California Department of Fish and Game 2010); Gaviota/CA/Pacific Ocean (1990, Sarver and Foltz 1993); Point Fermin, San Pedro-Scripps Instiute of Oceanography, La Jolla (Pister 2009, natural substrate); Los Angeles-San Diego/CA/San Pedro Bay-Mission Bay( Pister 2009, on riprap); 1st Record: San Diego/CA/Tijuana River estuary (mid 1980s-mid 1990s, Novoa et al. 2016); North, Norh-Central, Central, south-Central, South platforms/Santa Barbara Channel (2014, Page et al. 2019); 'South' oil platforms/CA/ San Pedro Bay (2014, Page et al., 2019)
Vectors
| Level | Vector |
|---|---|
| Alternate | Hull Fouling |
| Alternate | Ballast Water |
Regional Impacts
| Economic Impact | Fisheries | |
| Mussel aquaculture has been conducted in San Diego Bay, Agua Hedionda Lagoon and the Santa Barbara Channel, consisting of growing mussels on ropes from former oil platforms (Conte 1992; California Department of Fish and Game 2010). Websites indicate that the Santa Barbara Channel and Agua Hedionda operations continue (http://www.sbmariculture.com/shellfish.html www.ediblecommunities.com/sandiego/pages/.../afishionados.pdf). | ||
| Ecological Impact | Competition | |
| Mytilus trossulus (Bay Mussel) was present in southern California as indicated by the presence of mussels in prehistoric middens, and DNA testing of museum specimens (Carlton 1979; Geller 1999). In southern California, a rapid increase in mussel abundance in the 1940s (Coe 1946, cited by Carlton 1979), may have marked the invasion of M. galloprovincialis and the replacement of M. trossulus. Local observers cited dense settlements of mussels 'smothering' local fauna (Carlton 1979). In recent studies, M. trossulus and M. trossulus X M. galloprovincialis hybrids have been rare south of Point Conception (Sarver and Foltz 1993; Suchanek et al. 1997; Geller 1999; Rawson et al. 1999; Braby and Somero 2006). | ||
| Ecological Impact | Hybridization | |
| In recent sampling, hybrids between native M. trossulus and M. galloprovincialis are rare, but probably were much more abundant in initial stages of invasion. The fact that most detected hybrids are first-generation (F1) suggests little genetic exchange between populations and possible genetic incompatibility (Rawson et al. 1999). Genetic incompatibility between the two species could have sped up the decline of M. trossulus, once M. galloprovincialis became more abundant, due to wastage of gametes. | ||