Invasion History

First Non-native North American Tidal Record: 1987
First Non-native West Coast Tidal Record: 1987
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

In the past three decades, morphological and genetic surveys have shown that many of the mussel populations formerly recognized as ‘Mytilus edulis’ in the Northern and Southern Hemispheres, are other closely related species, M. trossulus and M. galloprovincialis (Mediterranean Mussel). These had been recognized either as species or subspecies, based on subtle morphological features. Additional species, in the Southern Hemisphere had been recognized either as species or subspecies, based on subtle morphological features, and later synonymized, and sometimes resurrected. These include M. chilensis in the Southeast Pacific, M. platensis in the Southwest Atlantic, and M. planulatus in the southwest Pacific (Zwabicka et al. 2019). Molecular methods have identified many mixed populations in transitional zones, in invaded regions, or at natural ecological boundaries, including hybrids of two or more species. Mytilus galloprovincialis, native to the Mediterranean and the Atlantic coast of southern Europe was shown to be introduced and widespread on the West Coast of North America, Asia, South Africa, and possibly elsewhere (McDonald and Koehn 1988; McDonald et al. 1991; Geller et al. 1994; Suchanek et al. 1997; Geller 1999; Rawson et al. 1999; Westfall and Gardner 2010). Mytilus edulis, in its current sense, is native to the North Atlantic, from Cape Hatteras, North Carolina and the Bay of Biscay to Newfoundland, Iceland, northern Norway, and the mouth of the Baltic. The native 'blue mussel' of the northern Northwest Atlantic (Maine-Labrador), Baltic Sea, and northern North Pacific (California and Japan to the Bering Sea) is M. trossulus (Bay Mussel) (McDonald et al. 1991; Hilbish et al. 2000).

Mytilus galloprovincialis was first described from the Mediterranean Sea, where it occurs mainly on the northern shore, and appears to be rare or absent from most of the Mediterranean, North African coast, and the Levantine basin. Its range extends through the Black Sea to the Sea of Azov (Hilbish et al. 2000; Shurova 2001; Smietanka et al. 2004). In the Atlantic, purebred populations are found from Morocco to the southern Bay of Biscay, and zones of co-occurrence and hybridization occur northward along the entire west coast of the British Isles (McDonald et al. 1991; Hilbish et al. 2000; Smietanka et al. 2004). 

The origins of Mytilus sp. in the southern hemisphere have been more difficult to interpret. Those in South Africa have been easily recognized as recently introduced M. galloprovincialis (Griffiths et al. 1992). However, populations in Australia, New Zealand, and southern South America, appear to have some genetic differences from Northern Hemisphere populations (Hilbish et al. 2000). Shells of Mytilus sp. are known from subfossil shell middens in Australia and New Zealand, predating European colonization. Genetic analysis suggests a prehistoric origin of Australasian Mytilus, from a ‘proto-galloprovincialis’ ancestor, with introgression of M. edulis genes (Daguin and Borsa 2000; Hilbish et al. 2000). Daguin and Borsa (2000) suggest that Australasian populations be recognized as a distinct subspecies of M. galloprovincialis, native to that region. The southern lineage in Australia is now recognized as a separate species, M. planulatus (Popovic et al. 2019; Zbawicka et al. 2019). Oyarzun et al. (2016) refer to the southern South American form as M. chilensis, and the South Atlantic form as M. platensis. Molecular surveys (Westfall and Gardner 2010; Colgan and Middlefart 2011) have indicated the presence of both a Southern Hemisphere M. galloprovincialis, and purebred Northern Hemisphere M. galloprovincialis as well as hybrids between northern M. galloprovincialis and M. edulis in Australia, New Zealand, and Chile. In a study of Mytilus in the Strait of Magellan, Oyarzun et al. (2016) found hybridization between Northern and Southern Hemisphere M. galloprovincialis, and both forms with M. edulis. Alsoat one location, there was hybridization with Southern M. galloprovincialis with Northern Hemisphere M. trossulus (Oyarzun et al. 2016).

Please note: In many parts of its introduced range, including the Pacific coast of North America, M. galloprovincialis has invaded other Mytilus communities, and was not detected until these regions were surveyed using biochemical techniques. Thus, dates of invasion are unknown in most cases, and the dates given on our maps are the dates of molecular analyses.

North American Invasion History:

Invasion History on the West Coast:

On the West Coast of North America, M. galloprovincialis has invaded communities formerly dominated by the similar M. trossulus, so the date of invasion is unknown. However, in southern California in the 1940s, a dramatic increase in abundance of 'Bay' or 'Blue' mussels was noticed, causing some naturalists to suspect either an invasion or a resurgence of a native species (Coe 1946, cited by Carlton 1979). The occurrence of M. galloprovincialis was first discovered in California (San Diego, Los Angeles Harbor, Port San Luis, San Francisco Bay, Muir Beach, and Tomales Bay) by amino-acid electrophoresis of samples collected in 1987 (McDonald and Koehn 1988). The invasion appears to have begun somewhere between Point Conception and San Diego, where the native M. trossulus is now rare or absent. Shipping during World War II is a possible vector. Mytilus galloprovincialis now occurs at least as far south as Punta La Mina del Fraile, Baja California, Mexico (31.2?N, Curiel-Ramirez and Caceres-Martinez 2004), and ranges north to the Strait of Georgia, British Columbia (~50?N) (Wonham 2004; Shields et al. 2010). The abundance of Mytilus galloprovincialis north of Monterey Bay appears to be fluctuating with oceanographic cycles, increasing rapidly in the 1990s, but now contracting during a cold phase of the Pacific Decadal Oscillation (Hilbish et al. 2010). The Mediterranean Mussel is physiologically adapted to be more competitive in warm waters than the native M. trossulus, and tends to outgrow and outbreed the native, under suitable conditions (Shinen and Morgan 2008; Braby and Somero 2006; Lockwood and Somero 2011a).

Currently, Mytilus galloprovincialis is dominant south of Monterey Bay, but in the region between Monterey Bay and Humboldt Bay their abundance has fluctuated. Mytilus galloprovincialis and its hybrids dominated many estuaries from 1990 to 1995 (Sarver and Foltz 1993; Suchanek et al. 1997; Rawson et al. 1999), comprising 40-75% of the mussels sampled, but dropped sharply after 2000, being only ~2% of the mussels sampled in 2005-2007 (Braby and Somero 2006; Hilbish et al. 2010). North of Humboldt Bay, to Cape Flattery, Washington reported frequencies of M. galloprovincialis are low and its establishment is uncertain (Sarver and Foltz 1993; Suchanek et al. 1997; Rawson et al. 1999).

Aquaculture of M. galloprovincialis in open waters in California is being carried out at several locations, including Agua Hedionda Lagoon, Santa Barbara Channel, Tomales Bay, and until recently, Humboldt Bay (Conte 1992; California Department of Fish and Game- Marine Region 2010). Aquaculture has probably played a role in expanding the range and maintaining the abundance of M. galloprovincialis in less favorable conditions. In Puget Sound and the Strait of Georgia, British Columbia, M. galloprovincialis and hybrids are locally common near ports, marinas and aquaculture operations, where introductions occur regularly, and where warmer, shallow, and confined waters provide better growing conditions. Extensive aquaculture of M. galloprovincialis began in the 1990s, and is carried out in many locations in Puget Sound and British Columbia (Heath et al. 1995; Anderson et al. 2002; Wonham 2004; Richoux et al. 2006; Elliott et al. 2008; Shields et al. 2008; Shields et al. 2010). In a few locations in the Strait of Georgia-Puget Sound region, M. galloprovincialis exceeded 25% of the mussels sampled (4 of 70 sites sampled, Wonham et al. 2004; 6 of 29 sites, Elliott et al. 2008, Puget Sound only). The most northern site where M. galloprovincialis is reported is Sayward, Vancouver Island (50° 23’ 31 N) (Shields et al. 2010).

Invasion History on the East Coast:

Mytilus galloprovincialis was observed in hull fouling in Halifax Harbor, Nova Scotia in 2007-2009 (Sylvester et al. 2011). It has likely been carried to many East coast ports. Detection of established populations would require molecular surveys.

Invasion History in Hawaii:

Mytilus galloprovincialis has been observed in Pearl Harbor, Oahu (in 1998, on the hull of USS Missouri, spawning in the harbor). Larvae were also detected in a US submarine ballast tank (Apte et al. 2000).

Invasion History Elsewhere in the World:

Mytilus galloprovincialis may have been first reported in the northwest Pacific in Kobe, Japan in 1934 (Kanamura 1935, cited by Wilkins 1983). Prior to that time, Mytilus mussels (M. trossulus) were known in Japan only from Hokkaido (Wilkins et al 1983). Extensive settlements of M. galloprovincialis occurred in south and central Japan (Wilkins et al. 1979; Inoue et al. 1997; Kurihara et al. 2009). Mytilus galloprovincialis colonized the Sea of Japan by 1941 (Iwasaki 2006) and Hong Kong by 1983 (Lee and Morton 1985). At the northern end of Japan, and the southern Pacific coast of Russia, they have formed a hybrid zone with M. trossulus (Skurikhina et al. 2004; Brannock et al. 2010). However, from 1978 to 2006, abundance of M. galloprovincialis decreased sharply on the eastern shore of Japan, possibly due to increasing water temperatures, while native mussels were less affected (Kurihara et al. 2009).

In southeastern Australia, New Zealand, and southern South America, the situation is complicated by the presence of apparently native Southern Hemisphere genotypes of M. galloprovincialis, resulting from a prehistoric natural migration (Daguin and Borsa 2000; Hilbish et al. 2000), and at the same time, introduced Northern Hemisphere genotypes, presumably introduced by shipping and aquaculture (Westfall and Gardner 2010; Colgan and Middlefart 2011; Gardner and Westfall 2012). One recent estimate is 100,000 to 600,000 for European M. galloprovincialis and the Australian form, now known as M. planulatus (Popovic et al. 2019). At the same time, introduced Northern Hemisphere genotypes, presumably introduced by shipping and aquaculture have become established and hybridize with native forms (Westfall and Gardner 2010; Colgan and Middlefart 2011; Gardner and Westfall 2012; Oyarzun et al. 2016). Northern genotypes have been found near ports and aquaculture operations, but also at some sites on open coastlines (Westfall and Gardner 2010; Colgan and Middlefart 2011). Multiple invasions have probably occurred in these regions, but the dates of introductions cannot be determined. However, one invasion in the remote Auckland Islands off New Zealand, now a restricted biosphere preserve, most likely occurred during 19th century seal-hunting operations (Westfall and Gardner 2010).

 

The extent of invasion of exotic Northern Hemisphere M. galloprovincialis in the Southern Hemisphere is contentious. Multiple studies have reported different degrees of invasion and hybridization in South America, Australia, New Zealand, and Sub-Antarctic Islands (Westfall and Gardner 2010; Colgan and Middlefart 2011; Oyarzun et al. 2016; Gardner and Westfall 2012; Zbawicka et al. 2019). Some the differences may depend on the degree of focus on ports and aquaculture versus less-disturbed habitats.

Popovic et al. (2019) found evidence for two separate invasions of Australia by European M. galloprovincialis, by populations from the Atlantic coast of Europe, and from the Mediterranean. Populations from Bateman's Bay in southhern New South Wales had a stronger contribution from Atlantic populations, while those from Sydney Harbour were closer to Mediterranean populations. Both populations had repeated hybridization with native M. planulatus (Popovic et al. 2019).  Zbawicka at al. al (2022) found M. galloprovincialis × M. planulatus on the south coast of Astralia from Western Australia to New South Waltes, varing in frequency from 30% (Port Arthur, Tasmania) to 97% (South Australia).  Hybrids were more dominant in mussel-farming operations. Of the 10 wild and farmed sites sampled, only one wild population was 100% M. planulatus (Zbawicka et al. 2022). Zbawicka et al. (2022) suggest aqaculture of M. planulatus to preserve the native species.


Description

Mytilus galloprovincialis has a smooth shell roughly shaped like an elongate triangle, with the beak forming the apex. The anterior margin is straight, while the posterior margin is broadly rounded. The surface is marked by concentric growth lines. The exterior color is black to bluish-black, or brownish, while the interior is white, with a violet margin, and a distinct muscle scar. The shell can reach a length (height) of 150 mm (Abbott 1974; Coan et al. 2000; Coan and Valentich-Scott, in Carlton 2007). Like other mussels, M. edulis clings to hard surfaces (rocks, logs, structures) by a cluster of byssus treads.

Mytilus galloprovincialis is part of the M. edulis species complex, which includes M. galloprovincialis, M. trossulus, and possibly other species (e.g. M. chilensis, M. desolationis, M. planulatus. M. platensis), whose distinctness is disputed (Westfall and Gardner 2010; Oyarzun et al. 2016; Zbawicka et al. 2022). Mytilus edulis tends to have a longer hinge plate and adductor muscle scar than either M. galloprovincialis or M. trossulus. However, overlap is considerable. The species are best distinguished morphologically by statistical analysis of multiple measurements (McDonald et al. 1991) or by molecular methods (McDonald et al. 1991; Heath et al. 1995; Shields et al. 2008; Westfall and Gardner 2010).

Larvae of M. galloprovincialis are described by Semenikhina et al. (2008). Late veligers are roughly egg-shaped, with a prominent eye-spot. Settlement occurs at 330-350 µm in Pacific Russia (Semenikhina et al. 2008). To our knowledge, larvae of M. edulis cannot be distinguished visually from those of M. galloprovincialis or M. trossulus.


Taxonomy

Taxonomic Tree

Kingdom:   Animalia
Phylum:   Mollusca
Class:   Bivalvia
Subclass:   Pteriomorphia
Order:   Mytiloida
Family:   Mytilidae
Genus:   Mytilus
Species:   galloprovincialis

Synonyms

Mytilus chilensis (Hupe, 1854)
Mytilus desolationis (Lamy, 1936)

Potentially Misidentified Species

Mytilus trossulus
Mytilus trossulus, the Bay Mussel, is native to the North Atlantic and North Pacific, ranging north to Alaska, Siberia, and Labrador. In European waters, it is primarily found in the Baltic Sea (McDonald et al. 1991, Hilbish et al. 2000).   


Mytilus aoteanus
Mytilus aoteanus (Powell 1958) was described from the Campbell and Auckland Islands. It had been treated as synonym of M. planulatus (Huber, in Appletans et al. 2019), but Zbawicka et al. (2019) found that it was genetically distinct.

Mytilus chilensis
Mytilus chilensis (Hupe 1854), described from the southeast Pacific, may be synonymous with the southern hemisphere genotype of M. galloprovincialis (McDonald et al. 1991; Westfall and Gardner 2010; Oyarzun et al. 2016). . However, Mytilus chilensis, described from the southeast Pacific, may be synonymous with the southern hemisphere genotype of M. galloprovincialis (McDonald et al. 1991; Westfall and Gardner 2010; Oyarzun et al. 2016). However, based on an analysis of Single Nucleoptide Polymorphisms (SNP's), Zbawicka et al. (2019) consider M. chilensis to be a distinct species.

Mytilus edulis
Mytilus edulis, the Blue Mussel, is native to the North Atlantic and North Pacific, ranging north to Newfoundland, Iceland, and Norway, and south to Virginia and Spain (McDonald et al. 1991; Hilbish et al. 2000).

Mytilus planulatus
Mytilus planulatus (Lamarck 1819) is native to Tasmania and New Zealand, and is genetically distinct from the northern Hemispshere Mytilus galloprovincialis groups (Popovic et al. 2019; Zbawicka et al. 2019).

Mytilus platensis
Mytilus platensis (d’Orbigny 1846), described from Argentina, was considered synonymous with the southern hemisphere genotype of M. galloprovincialis (McDonald et al. 1991; Westfall and Gardner 2010; Oyarzun et al. 2016). However, based on an analysis of Single Nucleoptide Polymorpishms (SNPs), Zbawicka et al. (2019) consider M. platensis to be a distinct species.

Ecology

General:

Mytilus galloprovincialis has separate sexes and individuals mature at one year of age or less. This species has a prolonged spawning season, and in some regions, spawns year round (Seed 1969). Fertilized eggs develop into a planktonic trochophore larva, then into a shelled veliger. Female M. galloprovincialis, fed different phytoplankton diets, produce means of 1.5-3.5 million eggs. The larvae settle at 330-350 µm, after about 2-4 weeks in the plankton (Satuito et al. 1994; Caceres-Martinez and Figueras 1998; Semenikhina et al. 2008; Lopez-Duarte et al. 2012). On the coast of San Diego County, California larvae dispersed over a mean distance of 35 km determined by genetic and trace-metal analysis, though a large proportion settled more locally, while a few (1.5%) dispersed for more than 125 km. There was extensive genetic exchange between bays and between open-coast and bay populations (Lopez-Duarte et al. 2012).

Larvae of M. galloprovincialis can settle and metamorphose on a wide variety of surfaces, including rock, wood and vegetation. Initially, juveniles can be quite mobile, using their byssus threads to move up and down, and attaching to drifting substrates such as vegetation. As they grow, they are attracted to other mussels. Extensive beds develop on rocky surfaces, but also on soft sediments, in which mussels are connected to each other and the substrate by byssus threads, creating a complex habitat (Robinson et al. 2007). Mussels are strong-filter feeders, and create substantial currents as they pump in water ingesting phytoplankton and other suspended material. They deposit the uneaten material as pseudofeces, creating deposits of silt around and within the mussel bed (Bertness 1999; Buschbaum et al. 2009).

Mediterranean Mussels are characteristic of shallow subtidal and intertidal zones, and can be subject to sharp changes in temperature when exposed to the air, and changes in salinity due to rainfall and river flow. Adult M. galloprovincialis can tolerate salinities of 10 PSU, but require at least 20 PSU for successful larval development (His et al. 1989). Populations in the Black Sea (~18 PSU) may have lower salinity tolerances.

Food:

Phytoplankton

Competitors:

Mytilus trossulus; Mytilus edulis; Perna perna

Trophic Status:

Suspension Feeder

SusFed

Habitats

General HabitatCoarse Woody DebrisNone
General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatVessel HullNone
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Tidal RangeLow IntertidalNone
Tidal RangeMid IntertidalNone
Vertical HabitatEpibenthicNone
Vertical HabitatLittoralNone

Life History


Tolerances and Life History Parameters

Maximum Temperature (ºC)31Experimental, ranges of 27.5-31 reported by authors cited by Hicks and McMahon (2002) and Schneider (2008).
Minimum Salinity (‰)10Experimental, mussels from Black Sea (Shurova 2001)
Maximum Salinity (‰)38Mediterranean salinity- this species probably tolerates higher salinities.
Minimum pH7.6Gestoso et al. 2015, 40-60% mortality, over 22 days (Gestoso et al. 2015)
Minimum Reproductive Temperature15Mussel larvae from Arcachon, France (Bay of Biscay) developed well at 15-25 C (His et al. 1989)
Maximum Reproductive Temperature25Mussel larvae from Arcachon, France (Bay of Biscay) developed well at 15-25 C, but (His et al. 1989)
Maximum Reproductive Salinity38Based on occurrence in Mediterranean Sea. Mussel larvae from Arcachon, France (Bay of Biscay) developed well at 20-35 PSU (His et al. 1989)
Minimum Duration26Japan, laboratory rearing, 20 C, Satuito et al. 1994
Maximum Duration40NW Spain, unspecified temperature- Caceres-Martinez and Figueras 1998
Minimum Length (mm)14Japan, Wilkins 1983
Maximum Length (mm)100Abbott 1974; Coan and Valentich-Scott, in Carlton 2007
Broad Temperature RangeNoneCold temperate-Warm temperate
Broad Salinity RangeNonePolyhaline-Euhaline

General Impacts

Mytilus galloprovincialis has been listed by the Invasive Species Specialist Group of the International Union for Conservation of Nature (IUCN) as one of the '100 worst invasive species.' However, its economic and ecological effects are complex. On the West Coast of the US, Japan, Chile, Australia, and South Africa, it has become an important aquaculture species (Inoue et al. 1997; Robinson et al. 2005; Elliott et al. 2008; Colgan and Middlefart 2011), but it has also interfered with aquaculture of other species, such as oysters (Chavanich et al. 2010). It can foul ships’ hulls and industrial-water systems (Chavanich et al. 2010). While it has hybridized and competed with native mussels and other shore invertebrates, its beds have created complex habitats and food supplies for some native organisms (Robinson et al. 2005).

Economic Impacts

Shipping- Mussels of the genus Mytilus are abundant and troublesome fouling organisms on ships, docks, jetties, pipes, and industrial water systems (Woods Hole 1952). They are rarely distinguished to species, but in Japan, where M. galloprovincialis invaded in the 20th century, they led to greatly increased ship fouling and the use of toxic fouling paints, including TBT, with negative effects on native mollusks (Chavanich et al. 2010).

Fisheries- Mytilus galloprovincialis is considered a highly desirable seafood species, and is widely gathered, fished, cultured, and eaten in its native and invaded ranges. Culture is usually done on racks, sometimes in the intertidal zone, or on ropes suspended from rafts or piers (Conte 1992). In North America, Mediterranean Mussels are cultured from California to British Columbia (Anderson 2002; Conte 1992; Wonham 2004; Elliott et al. 2008; California Department of Fish and Game 2010; BC Shellfish growers Association http://bcsga.ca/about/industry-encyclopedia/mussels). Mytilus galloprovincialis is cultured in Japan, Chile, Australia, and South Africa, and doubtless, in other regions as well (Inoue et al. 1997; Robinson et al. 2005; Colgan and Middlefart 2011). The ecological impacts of mass off-bottom culture of native or introduced mussels are great, and include alteration of water flow, increased sedimentation, alteration of nutrient fluxes, and provision of new habitat for native and non-indigenous fouling organisms, such as tunicates (McKindsey et al. 2011).

Industry- Mytilus galloprovincialis is considered to be the most expensive fouling organism of power plants in Japanese waters, causing major expenses for damage and cleaning (Iwasaki 2006). Its impacts in invaded areas may be difficult to recognize where it has replaced M. trossulus or the Southern Hemisphere form of M. galloprovincialis (Woods Hole Oceanographic Institution 1952).

Ecological Impacts

Competition- Many of the invasions of Northern Hemisphere M. galloprovincialis were initially undetected, because this mussel replaced other morphologically very similar members of the Mytilus galloprovincialis complex, primarily M. trossulus (Bay Mussel) in the North Pacific, but also the native Southern Hemisphere genotype of this species, in Australia, New Zealand and Chile (McDonald et al. 1991; Suchanek et al. 1997; Geller 1999; Hilbish et al. 2000; Westfall and Gardner 2010). In warm-temperate environments and full marine salinities, M. galloprovincialis outperforms M. trossulus (Braby and Somero 2006; Lockwood and Somero 2011), outgrowing and out-reproducing M. trossulus. It also engages in interference competition, by moving, out filtering, and smothering M. trossulus (Shinen and Morgan 2009). Examination of museum specimens and shells from Indian middens indicate that M. trossulus was the sole mussel species south of Point Concepcion, California, and has been completely replaced by M. galloprovincialis (Geller 1999). However, north of Monterey Bay, since 2000, changing ocean conditions and cooler temperatures associated with the Pacific Decadal Oscillation have shifted the competitive balance back to favoring M. trossulus. Long-term cyclic changes in the distribution of the two mussels are likely (Braby and Somero 2006; Hilbish et al. 2010; Lockwood and Somero 2011a, Lockwood and Somero 2011b). In shallow estuaries with warmer summer temperatures and variable salinities, such as San Francisco Bay, Puget Sound, and Georgia Strait, complex interactions between M. galloprovincialis and M. trossulus occur (Braby and Somero 2006). Extensive replacement of M. trossulus has also been seen in northern Japan (Daguin and Borsa 2000; Brannock et al. 2005). Interactions between the Northern Hemisphere and Southern Hemisphere genotypes of M. galloprovincialis have not yet been studied.

In several parts of the world, M. galloprovincialis has been observed to compete with other genera of mussels, and with other bivalves. In South Africa, it grows faster and has greater reproductive output than three species of native mussels (Aulacomya ater, Choromytilus meridionalis, and Perna perna; Branch and Stefanni 2004). Some of its advantage there may come from its virtual lack of parasites (Calvo-Ugarteburu and McQuaid 1998). It has largely replaced the smaller native mussel Aulacomya ater in the intertidal zone on the West Coast of South Africa (Branch and Steffani 2004; Griffiths et al. 2005; Branch et al. 2008). On the south coast of South Africa, it has had a stand-off, resulting in coexistence with the native P. perna, with the more desiccation-resistant and prolific, but less firmly attached M. galloprovincialis predominating in the upper intertidal, while P. perna resists waves and post-recruitment mortality better than the invader (Bownes and McQuaid 2006; Zardi et al. 2007; Nicastro et al. 2008). In Japan, Septifer virgatus (a native mussel) and Crassostrea gigas (Pacific Oyster) have been reportedly replaced in many habitats (Chavanich et al. 2010).

Mytilus galloprovincialis, like other mussels, is a major ecosystem engineer on rocky shores, so it competes not just with other attached bivalves, but competes for space with such shore species as limpets, anemones, and seaweeds. In southern California, dense settlements of mussels in the 1940s (probably M. galloprovincialis) were reportedly 'smothering' local fauna (Carlton 1979). In South Africa, M. galloprovincialis affects two species of native limpets (Scutellastra granularis, S. argenvillei) by depriving them of space for grazing on rocky shores (Branch and Steffani 2004; Griffiths et al. 2005; Branch et al. 2008). In Japan, M. galloprovincialis is reported to displace the barnacle Chthamalus challengeri, and the seaweed Sargassum fusiformis (Chavanich et al. 2010).

Habitat Change- Mytilus galloprovincialis is a major ecosystem engineer of shore habitats, occupying large spaces in the intertidal zone, but also creating a complex 3-dimensional environment, with much hard surface for attachment by other organisms, and sheltered niches where mobile organisms can hide. Where M. galloprovincialis has replaced M. trossulus, these impacts may have been small, but where M. galloprovincialis invasions have greatly increased the biomass, structure, and intertidal range of mussel beds, the impacts are significant. On the west coast of South Africa, while M. galloprovincialis has largely replaced the native mussel Aulacomya ater, small specimens of A. ater extend higher up in the intertidal zone, because of the shelter offered by the dense beds of M. galloprovincialis. Similarly, while large specimens of the limpet Scutellastra granularis are deprived of space for grazing, smaller specimens can utilize mussel shells as substrate, reach high densities, and increase larval output, in spite of being unable to reach full adult size. Another limpet, S. argenvillei, is displaced from the mussel beds because it cannot reach reproductive size there (Branch and Stefanni 2004; Branch et al. 2008). Overall, in this region, spreading beds of M. galloprovincialis increased the complexity of the habitat and also decreased the patchiness of the intertidal habitat (Robinson et al. 2007). In central and southern Japan, where no native Mytilus species were present, the invasion of M. galloprovincialis has resulted in the mass deposition of pseudofeces in the sediment, creating hypoxic conditions (Chavanich et al. 2010).

Food/Prey- The presence of M. galloprovincialis may increase food availability for predators in many invaded areas, since it tends to be larger than M. trossulus, and because it apparently reaches higher densities than many native mussels. One case is the threatened African Black Oystercatcher, Haematopus moquini, on the west coast of South Africa, which switched its diet to M. galloprovincialis and increased its brood size (Griffiths et al. 1992; Hockey and Van Erkom Schurink 1992).

Hybridization- Mytilus galloprovincialis has extensively hybridized with the northern Bay Mussel M. trossulus in the northeast and northwest Pacific, sometimes at very high frequencies (up to 70%). On the west coast of the US, hybrids are rare south of Monterey Bay, where M. trossulus is now virtually absent. The frequency of hybridization decreased from the 1990s to the 2000s, apparently due to cyclic ocean temperature changes (El Nino and the Pacific Decadal Oscillation) (McDonald et al. 1991; Sarver and Foltz 1993; Rawson et al. 1999; Braby and Somero 2006; Hilbish et al. 2010). North of California, hybridization was rarer, and more frequent near ports and mussel farms (Elliott et al. 2008; Shields et al. 2010). The hybrid zone in the northwest Pacific runs from the Vladivostok area, Russia, to northern Japan (Suchanek et al. 1997; Matsumasa et al. 1999; Skurikhina et al. 2004; Brannock and Hilbish 2010). Although rates of F1 (first-generation hybrids) are often high, the frequency of F2 hybrids is small, indicating that little genetic exchange is occurring between the two species (Rawson et al. 1999; Brannock and Hilbish 2010). This result could indicate poor survival or reduced fertility of hybrids, due to genetic incompatibility (Rawson et al. 1999).

In a recent survey of Mytilus populations in British Columbia, Crego-Prieto et al. (2015) found that M. galloprovincialis X M. trossulus hybrids were most abundant near mussel farms, and on open coasts, compared to estuaries. They suggest hybridization with M. trossulus should be limited by not pemitting farming of M. galloprovincialis north of its present range in the province, and by restricting farming to sheltered, estuarine waters (Crego-Prieto et al. 2015). Hybridization has also been observed between native Southern Hemisphere M. galloprovincialis and introduced Northeast Atlantic lineages at several locations near ports in New Zealand. This introgression is considered a threat to the genetic biodiversity native mussel populations, particularly on remote southern ocean islands (Gardner et al. 2016).


Regional Impacts

NEP-VNorthern California to Mid Channel IslandsEcological ImpactCompetition
In this bioregion, the native M. trossulus once was the sole mussel species. Based on field (Bodega Marine Laboratory, open coast) and lab experiments, Mytilus galloprovincialis displaces M. trossulus (Bay Mussel) and M. californianus (Sea Mussel) through interference competition (limiting movement, outfiltering, and overgrowing) with the native mussels as well as simply outgrowing them (Shinen and Morgan 2009). Physiological observations indicate that M. galloprovincialis is better adapted metabolically to warmer temperatures than M. trossulus, while M. trossulus is favored by cooler temperatures (Braby and Somero 2006; Lockwood and Somero 2011a). Mytilus trossulus is better adapted to low salinities (Lockwood and Somero 2011a). Consequently, climatic cycles such as the Pacific Decadal Oscillation and El Nino can cause cyclic fluctuations in the range, abundance, and hybridization of the two species (Braby and Somero 2006; Hilbish et al. 2010; Lockwood and Somero 2011a b).
P112_CDA_P112 (Bodega Bay)Ecological ImpactCompetition
Based on field (Bodega Marine Laboratory, open coast) and lab experiments, Mytilus galloprovincialis displaces M. trossulus and M. californianus through interference competition (limiting movement, outfiltering, overgrowing) with the native mussels as well as simply outgrowing them (Shinen and Morgan 2009). In 1990-1991in Bodega Bay, purebred M. galloprovincialis comprised ~10% of total mussels sampled (Sarver and Foltz 1993), but ~60% in a 1994 survey (Rawson et al. 1999) and in 2002, at 2 sites, ~30-85% (Braby and Somero 2006).
P090San Francisco BayEcological ImpactHybridization
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.
NEP-VNorthern California to Mid Channel IslandsEcological ImpactHybridization
This species was first detected in molecular surveys which began in 1985 (McDonald et al. 1991). Central California is a hybrid zone for Mytilus galloprovincialis and M. trossulus. Since molecular studies began in the late 1980s and early 1990s, both species and their hybrids have coexisted but have varied in abundance with cyclic 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 (Braby and Somero 2006). The fact that most detected hybrids are first-generation (F1) suggests little genetic exchange between populations and possible genetic incompatibility (Rawson et al. 1999). In earlier surveys, the hybrid zone extended north of Cape Mendocino (McDonald et al. 1991; Sarver and Foltz 1993; Rawson et al. 1999). In 2005-2007, the frequency of M. galloprovinicalis and hybrids, north of 39°N declined from ~15-70% to about 5%. This change was attributed to lower temperatures, resulting from the Pacific Decadal Oscillation (Hilbish et al. 2010).
NWP-3bNoneEcological ImpactCompetition
The invasion of M. galloprovincialis has reduced native species and altered benthic communities by the development of dense mussel beds. Among species which have been partially replaced are: Crassostrea gigas (Pacific Oyster), Septifer virgatus (a native mussel), Chthamalus challengeri, and the seaweed Sargassum fusiformis (Chavanich et al. 2010).
NWP-3bNoneEcological ImpactHabitat Change
Large beds of M. galloprovincialis have altered benthic communities through the mass deposition of pseudofeces in the sediment, creating hypoxic conditions (Chavanich et al. 2010).
NWP-3bNoneEconomic ImpactFisheries
The invasion of M. galloprovincialis has interfered with oyster culture, causing a 35% reduction in harvests in Hiroshima Bay, amounting to about 500 million Japanese yen (Chavanich et al. 2010). On the other hand, M. galloprovincialis were cultured in Matoya Bay, Japan (Inoue et al. 1997). Extensive aquaculture of mussels is likely in Japan.
NWP-3bNoneEconomic ImpactShipping/Boating
Greatly increased ship fouling due to M. galloprovincialis had resulted in a great increase in the use of toxic fouling paints, including TBT, with negative effects on native mollusks (Chavanich et al. 2010).
NWP-4aNoneEcological ImpactCompetition
The invasion of M. galloprovincialis has reduced native species and altered benthic communities by the development of dense mussel beds. Among species which have been partially replaced are: Crassostrea gigas (Pacific Oyster), Septifer virgatus (a native mussel), Chthamalus challengeri, and the seaweed Sargassum fusiformis (Chavanich et al. 2010). In this bioregion, the native M. trossulus was once the sole mussel species of Mytilus, confined to the west coast of Hokkaido and the Russian coast (Skurikhina et al. 2004; Brannock and Hilbish 2010). In 2006, all of the mussels sampled by Brannock and Hilbish (2010) on the west coast of Hokkaido were M. galloprovincialis.
NWP-4aNoneEcological ImpactHabitat Change
Large beds of M. galloprovincialis have altered benthic communities through the mass deposition of pseudofeces in the sediment, creating hypoxic conditions (Chavanich et al. 2010).
NWP-4aNoneEconomic ImpactFisheries
The invasion of M. galloprovincialis has interfered with oyster culture (Chavanich et al. 2010).
NWP-4aNoneEconomic ImpactShipping/Boating

Greatly increased ship fouling due to M. galloprovincialis had resulted in a great increase in the use of toxic fouling paints, including TBT, with negative effects on native mollusks (Chavanich et al. 2010). A predatory snail, Reishia luteostoma (as Reishia bronni(, was tested as a potential biocontrol for Mytius galloprovincialis.  It cleared small areas  of  mussels effectively, but rearing large numbers of snails is limiting (Kim et al. 2022).

NWP-4bNoneEcological ImpactCompetition
The invasion of M. galloprovincialis has reduced native species and altered benthic communities by the development of dense mussel beds. Among species which have been partially replaced are: Crassostrea gigas (Pacific Oyster), Septifer virgatus (a native mussel), Chthamalus challengeri, and the seaweed Sargassum fusiformis (Chavanich et al. 2010). At 5 locations on the south coast of Hokkaido, where M. trossulus was once the sole mussel species, purebred M. galloprovincialis comprised substantial portions of the mussels sampled (28 to 78%), while purebred M. trossulus were 14-73% (Brannock and Hilbish 2010).
NWP-4bNoneEcological ImpactHabitat Change
Large beds of M. galloprovincialis have altered benthic communities through the mass deposition of pseudofeces in the sediment, creating hypoxic conditions (Chavanich et al. 2010).
NWP-4bNoneEcological ImpactHybridization
In northern Japanese waters, extensive hybridization between M. galloprovincialis and M. trossulus has occurred (Suchanek et al. 1997; Matsumasa et al. 1999; Brannock et al. 2009; Chavanich et al. 2010).
P080Monterey BayEcological ImpactHybridization
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).
P086_CDA_P086 (San Francisco Coastal South)Ecological ImpactHybridization
~12% of mussels examined at Half Moon Bay were hybrids (M. trossulus X M. galloprovincialis), compared to 24% purebred M. trossulus (Rawson et al. 1999).
P095_CDA_P095 (Tomales-Drakes Bay)Ecological ImpactHybridization
In 1994-1995, ~16% of mussels examined at Muir Beach were hybrids (M. trossulus X M. galloprovincialis) compared with 56% purebred M. trossulus (Rawson et al. 1999). Changing environmental conditions (declining water temperatures) due to climate cycles, have probably reduced the frequency of M. galloprovincialis (Braby and Somero 2006; Hilbish et al. 2010).
NEP-IVPuget Sound to Northern CaliforniaEconomic ImpactFisheries
Mussel aquaculture was conducted in Humboldt Bay starting in 1992, but had ceased by 2008 (Conte 1992; California Department of Fish and Game 2010).
NEP-VIPt. Conception to Southern Baja CaliforniaEconomic ImpactFisheries
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). 
P065_CDA_P065 (Santa Barbara Channel)Economic ImpactFisheries
Mussel (M. galloprovincialis) aquaculture has been conducted in San Diego Bay and the Santa Barbara Channel, involving growing mussels on ropes from former oil platforms (Conte 1992; California Department of Fish and Game 2010). Websites indicate that the Santa Barbara Channel operations continue (http://www.sbmariculture.com/shellfish.html).
NEP-VNorthern California to Mid Channel IslandsEconomic ImpactFisheries
Mussel aquaculture has been conducted in Tomales Bay (Conte 1992; California Department of Fish and Game 2010). Websites indicate that these operations continue (http://tomalesbayoysters.com/).
P110Tomales BayEconomic ImpactFisheries
Mussel aquaculture has been conducted in Tomales Bay (Conte 1992; California Department of Fish and Game 2010). Websites indicate that these operations continue (http://tomalesbayoysters.com/).
NEP-IIIAlaskan panhandle to N. of Puget SoundEconomic ImpactFisheries
Extensive aquaculture of M. galloprovincialis is conducted in waters of British Columbia and Puget Sound (Anderson et al. 2002; Wonham 2004; Elliott et al. 2008; BC Shellfishgrowers Association http://bcsga.ca/about/industry-encyclopedia/mussels/)
NEP-IIIAlaskan panhandle to N. of Puget SoundEcological ImpactCompetition
In the Strait of Georgia and Puget Sound, where M. trossulus once was the sole species, the frequency of M. galloprovincialis is greatest in protected waters near marinas, shipping harbors, and aquaculture sites, sites of likely introduction, but also shallow, warmer waters favorable to the growth of the introduced mussel. At 4 of about 70 sites in this bioregion, purebred M. galloprovincialis exceeded 25% of sampled mussels (Wonham 2004). Elliott et al. (2008), sampling more selectively in Puget Sound found 6 of 29 sites in which frequencies of M. galloprovincialis comprised more than 25% of the sampled mussels. In most sites of the bioregion (Heath et al. 1995; Wonham 2004; Sheilds et al. 2010), the abundance of M. trossulus and its hybrid are so low than competitive impacts on M. trossulus are likely to be small.
P290Puget SoundEconomic ImpactFisheries
Extensive aquaculture of M. galloprovincialis is conducted in waters of British Columbia and Puget Sound (Anderson et al. 2002; Wonham 2004; Elliott et al. 2008; http://www.taylorshellfishfarms.com/ourStore-mussels-mediterranean).
P290Puget SoundEcological ImpactHybridization
Locally high rates of hybridization (10-57% of sampled mussels) between Mytilus galloprovincialis and native M. trossulus have been found in locations in Puget Sound near marinas, ports, and shellfish farms (Anderson et al. 2002; Wonham 2004, Elliott et al. 2008).
NEP-VIPt. Conception to Southern Baja CaliforniaEcological ImpactCompetition
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).
NEP-VIPt. Conception to Southern Baja CaliforniaEcological ImpactHybridization
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.
P020San Diego BayEcological ImpactCompetition
Competition with, and nearly complete replacement of, native M. trossulus occurred in San Diego Bay, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997). See the discussion of the bioregion for details.
P020San Diego BayEcological ImpactHybridization
Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details.
P030Mission BayEcological ImpactCompetition
Competition with, and nearly complete replacement of, native M. trossulus occurred in Mission Bay, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997). See the discussion of the bioregion for details.
P030Mission BayEcological ImpactHybridization
Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion of the bioregion for details.
P022_CDA_P022 (San Diego)Ecological ImpactCompetition
Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997). At this time, very heavy settlement of Mytilus 'edulis' occurred at the La Jolla pier, and was accompanied by a decline in recruitment of M. californianus, the native Sea Mussel (Coe 1946, cited by Carlton 1979).
P022_CDA_P022 (San Diego)Ecological ImpactHybridization
Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion of the bioregion for details.
P023_CDA_P023 (San Louis Rey-Escondido)Ecological ImpactCompetition
Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997).
P023_CDA_P023 (San Louis Rey-Escondido)Ecological ImpactHybridization
Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion of the bioregion for details.
P040Newport BayEcological ImpactCompetition
Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997). At this time, during a very heavy settlement of Mytilus 'edulis' in Newport Bay 'everything is smothered' (Roestler, in Burch 1946, cited by Carlton 1979).
P040Newport BayEcological ImpactHybridization
Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details.
P050San Pedro BayEcological ImpactCompetition
Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997).
P050San Pedro BayEcological ImpactHybridization
Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details.
P060Santa Monica BayEcological ImpactCompetition
Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997).
P060Santa Monica BayEcological ImpactHybridization
Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details.
P062_CDA_P062 (Calleguas)Ecological ImpactCompetition
Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997).
P062_CDA_P062 (Calleguas)Ecological ImpactHybridization
Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details.
P064_CDA_P064 (Ventura)Ecological ImpactCompetition
Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997).
P064_CDA_P064 (Ventura)Ecological ImpactHybridization
Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details.
P065_CDA_P065 (Santa Barbara Channel)Ecological ImpactCompetition
Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997).
P065_CDA_P065 (Santa Barbara Channel)Ecological ImpactHybridization
Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. In 2010, the Santata Barbara population was found to be pure M. galloprovincialis (Saarman and Pogson 2015).
P090San Francisco BayEcological ImpactCompetition
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).
P069_CDA_P069 (Central Coastal)Ecological ImpactCompetition
Mytilus galloprovincialis continues to compete with and dominate native M. trossulus south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010). See the bioregion discussion for details.
P069_CDA_P069 (Central Coastal)Ecological ImpactHybridization
Extensive hybridization between Mytilus galloprovincialis with native M. trossulus continues to occur south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010).
P073_CDA_P073 (Central Coastal)Ecological ImpactCompetition
Mytilus galloprovincialis continues to compete with and dominate native M. trossulus south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010). See the bioregion discussion for details.
P073_CDA_P073 (Central Coastal)Ecological ImpactHybridization
Extensive hybridization between Mytilus galloprovincialis with native M. trossulus continues to occur south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010).
P080Monterey BayEcological ImpactCompetition
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).
P070Morro BayEcological ImpactCompetition
Mytilus galloprovincialis continues to compete with and dominate native M. trossulus south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010). See the bioregion discussion for details.
P070Morro BayEcological ImpactHybridization
Extensive hybridization between Mytilus galloprovincialis with native M. trossulus continues to occur south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010).
P086_CDA_P086 (San Francisco Coastal South)Ecological ImpactCompetition
In 1994-95, 64% of mussels at Half Moon Bay were purebred M. galloprovincialis, while 24% were M. trossulus (Rawson et al. 1999). Changing environmental conditions (declining water temperatures) due to climate cycles, have reduced the frequency of M. galloprovincialis to ~35% (Hilbish et al. 2010).
P095_CDA_P095 (Tomales-Drakes Bay)Ecological ImpactCompetition
In 1994-1995, about 32% of mussels examined at Muir Beach were purebred M. galloprovincialis, while 52% were M. trossulus (Rawson et al. 1999).
P110Tomales BayEcological ImpactCompetition
In 1990-1991, ~90% of mussels sampled in Tomales Bay were M. galloprovincialis (Sarver and Foltz 1993; Suchanek et al. 1997), while only ~5-10% were M. trossulus. In 2002, 60% were M. galloprovincialis (Braby and Somero 2006). The continued dominance of the introduced mussel here, while declining in nearby estuaries (Hilbish et al. 2010), may have been a result of ongoing aquaculture operations. 
P112_CDA_P112 (Bodega Bay)Ecological ImpactHybridization
Mytilus galloprovincialis X M. trossulus hybrids comprised ~0-5% of total mussels sampled (Sarver and Foltz 1993), about 15% in a 1994 survey (Rawson et al. 1999) and in 2002, at 2 sites, ~10-15% (Braby and Somero 2006).
P114_CDA_P114 (Gualala-Salmon)Ecological ImpactCompetition
In 1994-1995, at Gualala Point and Bodega Head, purebred M. galloprovinialis comprised 42-45% of the mussels sampled, compared to 40-44% of native M. trossulus (Rawson et al. 1999). Changing environmental conditions (declining water temperatures) due to climate cycles, have probably reduced the frequency of M. galloprovincialis (Braby and Somero 2006; Hilbish et al. 2010).
P114_CDA_P114 (Gualala-Salmon)Ecological ImpactHybridization
Mytilus galloprovincialis X M. trossulus hybrids comprised 14% of total mussels sampled in a 1994-1995 survey (Rawson et al. 1999).
P116_CDA_P116 (Big Navaro-Garcia)Ecological ImpactCompetition
In 1994-1995, purebred M. galloprovincialis comprised ~50% of the mussels sampled at Shelter Cove, compared to about ~30% for purebred M. trossulus (Rawson et al. 1999). However, the percentage decline to ~5% by 2005-2007, apparently because of lower temperatures resulting from the Pacific Decadal Oscillation, made M. galloprovincialis less competitive (Hilbish et al. 2010).
P116_CDA_P116 (Big Navaro-Garcia)Ecological ImpactHybridization
In 1994-1995, M. galloprovincialis X M. trossulus hybrids comprised 12-20% of the mussels at Shelter Cove. In 2005-2007, the frequency of hybrids declined sharply, to about 1-2% (Hilbish et al. 2010), apparently due to lower temperatures resulting from the Pacific Decadal Oscillation, making M. galloprovincialis less competitive (Hilbish et al. 2010).
P117_CDA_P117 (Mattole)Ecological ImpactCompetition
In 1994-1995, purebred M. galloprovincialis comprised ~74% of mussels sampled at Cape Mendocino, while purebred M. trossulus were 18% (Rawson et al. 1999). In 2005-2007, the frequency of M. galloprovincialis and hybrids declined from ~20-40% to about 5%. This change was attributed to lower temperatures resulting from the Pacific Decadal Oscillation (Hilbish et al. 2010).
NEP-IVPuget Sound to Northern CaliforniaEcological ImpactCompetition
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).
NEP-IVPuget Sound to Northern CaliforniaEcological ImpactHybridization
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).
P130Humboldt BayEconomic ImpactFisheries
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).
P130Humboldt BayEcological ImpactCompetition
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).
P130Humboldt BayEcological ImpactHybridization
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).
NEP-IIIAlaskan panhandle to N. of Puget SoundEcological ImpactHybridization
In the Strait of Georgia and Puget Sound, frequency of M. galloprovincialis X M. trossulus hybrids occasionally exceeds 10% near marinas, shipping harbors, and aquaculture sites (11 of ~70 BC-Puget Sound sites listed, Wonham et al. 2004; 15 of 29 Puget Sound sites listed by Elliott et al. 2008; 1 of 20 Strait of Georgia sites, sampled by Shields et al. 2010). Hybridization impacts of M. galloprovincialis are likely to be localized in shallow, protected, human-impacted embayment's.
P290Puget SoundEcological ImpactCompetition
In Puget Sound, where M. trossulus was once the sole mussel species, the frequency of M. galloprovincialis is greatest in protected waters near areas of likely introduction, including marinas, shipping harbors, and aquaculture sites, but also shallow, warmer waters favorable to the growth of the introduced mussel. At 4 of about 60 sites in this bioregion, purebred M. galloprovincialis exceeded 25% of the mussels sampled (Wonham 2004). Elliott et al. (2008), sampling more selectively in Puget Sound, found 6 of 29 sites in which frequencies of M. galloprovincialis comprised more than 25% of the sampled mussels. In most sites in Puget Sound (Wonham 2004; Sheilds et al. 2010), the abundance of M. trossulus and its hybrid are so low that competitive impacts on M. trossulus are likely to be small.
P117_CDA_P117 (Mattole)Ecological ImpactHybridization
In 1994-1995, purebred M. galloprovincialis comprised ~74% of mussels sampled at Cape Mendicino, while purebred M. trossulus were 18% (Rawson et al. 1999). In 2005-2007, the frequency of M. galloprovincialis and hybrids declined from ~20-40% to about 5%. This change was attributed to lower temperatures, resulting from the Pacific Decadal Oscillation (Hilbish et al. 2010).
NWP-5NoneEcological ImpactCompetition
At 6 of 8 sites on the north shore of Hokkaido, where M. trossulus once was the sole mussel species, M. galloprovincialis comprised more than 50% of mussels sampled in 2006 while purebred M. trossulus were 7-24% (Brannock and Hilbish 2010).
NWP-5NoneEcological ImpactHybridization
The percentage of M. galloprovincialis X M. trossulus hybrids at 8 sites on the north shore of Hokkaido ranged from 0 to 71%. However, there was no evidence for introgression between the two species, suggesting genetic incompatibility and poor fertility of first generation hybrids, or poor survival of later generations (Brannock and Hilbish 2010).
NWP-4bNoneEconomic ImpactFisheries
Mussels (M. galloprovincialis) were cultured in Hirota Bay, Japan (Inoue et al. 1997). Extensive aquaculture of mussels is likely in Japan.
NWP-4bNoneEconomic ImpactShipping/Boating
Greatly increased ship fouling due to M. galloprovincialis had resulted in a great increase in the use of toxic fouling paints, including TBT, with negative effects on native mollusks (Chavanich et al. 2010).
NWP-4aNoneEcological ImpactHybridization
In recent genetic surveys, purebred Mytilus galloprovincialis was the sole Mytilus species in most of the Sea of Japan, but in Pos'yet Bay near Vladivostok, although no purebred M. galloprovincialis were found, 9% of the mussels were M. trossulus X M. galloprovincialis hybrids (Skurikhina et al. 2004).
NWP-3aNoneEcological ImpactCompetition
The invasion of M. galloprovincialis has reduced native species and altered benthic communities by the development of dense mussel beds. Among species which have been partially replaced are: Crassostrea gigas (Pacific Oyster), Septifer virgatus (a native mussel), Chthamalus challengeri, and the seaweed Sargassum fusiformis (Chavanich et al. 2010).
NWP-3aNoneEcological ImpactHabitat Change
Large beds of M. galloprovincialis have altered benthic communities through the mass deposition of pseudofeces in the sediment, creating hypoxic conditions (Chavanich et al. 2010).
NWP-3aNoneEconomic ImpactShipping/Boating
Greatly increased ship fouling due to M. galloprovincialis resulted in a great increase in the use of toxic fouling paints, including TBT, with negative effects on native mollusks (Chavanich et al. 2010).
AUS-IXNoneEconomic ImpactFisheries
Mytilus galloprovincialis is actively cultured in Tasmania (Colgan and Middlefart 2011, http://www.springbayseafoods.com.au/spring-bay-mussels).
WA-IVNoneEcological ImpactCompetition
Mytilus galloprovincialis grows faster and has greater reproductive output than the three mussel species native to South Africa, Aulacomya ater, Choromytilus meridionalis, and Perna perna (Branch and Stefanni 2004). Part of this advantage may come from the near-absence of parasites in M. galloprovincialis (Calvo-Ugarteburu and McQuaid 1998).

On the west coast of the Cape region of South Africa, M. galloprovincialis largely replaced the slower-growing native mussel Aulacomya ater and the native limpet Scutellastra granularis in the mid-intertidal zone. The abundance of A. ater decreased by 80% between 1979 and 1988. Mussels also excluded larger adult S. granularis by competing for substrate. A second native limpet, Scutellastra argenvillei, is excluded by M. galloprovincialis on exposed shores, but dominates on semi-exposed shores where M. galloprovincialis is less abundant due to lower recruitment (Branch and Steffani 2004; Griffiths et al. 2005; Branch et al. 2008). Another native mussel, Choromytilus meridionalis, was less affected because it extended further into subtidal areas and is more tolerant of sand than M. galloprovincialis (Griffiths et al. 1992). Overall, the invasion of M. galloprovincialis increased the structural complexity of the upper zones of the rocky intertidal, crating microhabitats. By 2012, the density of M. galloprovincialis declined, as it was partially replaced in the upper intertidal by the invading barnacle Balanus glandula. By this time, structual complexity had decreased to pre-1980 levels. A new mussel invader, Semimytilus algosus, native to the Pacific coast of South America was predicted to become established, but not dominant, because of lower efficiency of fof utilization, based on single=species feeding experiments (Alexander et al. 2015).
WA-IVNoneEcological ImpactHabitat Change
On the west coast of South Africa, Mytilus galloprovincialis colonized a wider tide range than the native mussels, since it is more desiccation resistant (Hockey and Van Erkom Schurink 1992). Its beds are composed of multiple layers of mussels, in contrast to the single layers of other species. Consequently, they provide shelter from wave action and desiccation for other biota dwelling among them. The spreading beds increased the complexity of the habitat and also decreased the patchiness of the intertidal habitat (Robinson et al. 2007).

The dense beds of M. galloprovincialis, while largely replacing the native Aulacomya ater, permitted small A. ater to extend their range upward on the shore, by providing shelter within the matrix of the invading mussels' shells. Similarly, the shells of M. galloprovincialis, while excluding the larger adult limpets Scutellastra granularis, provided substrate for young recruiting limpets (Griffiths et al. 1992; Branch and Steffani 2004; Branch et al. 2008). Mussel beds of M. galloprovincialis actually support a very high density of S. granularis, although the size and fecundity of the limpets are reduced. Another species of limpet, S. argenvillei, is more severely affected because it can just barely reach reproductive size when growing on mussels, and so is quite rare in M. galloprovincialis beds (Branch and Stefanni 2004; Branch et al. 2008). By 2002, the invasion of M. galloprovincialis greatly increased the structural complexity of the upper intertidal, enabling many lower-intertidal species to colonize new microhabitats higher on the shore. By 2012, M. galloprovincialis had declined in the upper intertidal, and was largely replaced by the barnacle Balanus glandula. As a result, habitat complexity returned to pre-invasion (1980) levels (Sadchatheeswaram and Branch 2015).
WA-IVNoneEcological ImpactFood/Prey
The increased biomass provided by M. galloprovincialis provided increased food stocks for predators, such as the African Black Oystercatcher, Haematopus moquini, which shifted its diet from A. ater to M. galloprovincialis, and increased its brood size (Griffiths et al. 1992; Hockey and Van Erkom Schurink 1992). A native whelk, Trochia cingulata shifted its food preference from the native Aulacomya atra to the introduced M. galloprovincialis and Semimytilus algosus, and also shifted its drilling behavior (Alexander et al. 2015).
WA-IVNoneEconomic ImpactFisheries
Mussels in South Africa have been traditionally important for subsistence harvesting. Mytilus galloprovincialis has increased the available stock, and also created opportunities for aquaculture (Hockey and Van Erkom Schurink 1992). The mussel culture industry in South Africa is based on M. galloprovincialis (Robinson et al. 2005).
WA-VNoneEcological ImpactCompetition
Mytilus galloprovincialis grows faster and has greater reproductive output than the three mussel species native to South Africa, Aulacomya ater, Choromytilus meridionalis, and Perna perna (Branch and Stefanni 2004). Part of this advantage may come from the near-absence of parasites in M. galloprovincialis (Calvo-Ugarteburu and McQuaid 1998).

On the south coast of South Africa, the dominant native mussel is Perna perna (Bownes and McQuaid 2006; Nicastro et al. 2007; Zardi et al. 2007). Over a 3-year period, cover and density of M. galloprovincialis increased in the upper intertidal, while P. perna decreased. Cover was lower for M. galloprovincialis in the the lower intertidal than for P. perna, apparently due to higher post-recruitment mortality. The two species appeared to coexist at the two locations (Plettenberg Bay and Tsitsikamma) studied (Bownes and McQuaid 2006). Major factors in this zonation were higher reproductive output in M. galloprovincialis and greater byssus (attachment) strength in P. perna (Zardi et al. 2007). The two species show different strategies in response to wave disturbance, M. galloprovincialis suffering greater mortality due to weaker attachment, but moving more actively as adults and recruiting more rapidly, while P. perna is more likely to survive in place (Nicastro et al. 2008). Food competition does not seem to be important. Stable sioptope and fatty-acid profiles of the two mussels were motly similar (Puccinelli et al. 2017).
WA-VNoneEcological ImpactHabitat Change
Habitat effects on M. galloprovincialis may be smaller on the south coast than on the west coast of South Africa, since this mussel forms single-layer beds on the south coast, probably due to lower productivity (Phillips 1994, cited by Robinson et al. 2005).
WA-VNoneEconomic ImpactFisheries
Mussels in South Africa have been traditionally important for subsistence harvesting. Mytilus galloprovincialis has increased the available stock, and also created opportunities for aquaculture (Hockey and Van Erkom Schurink 1992). The mussel culture industry in South Africa is based on M. galloprovincialis (Robinson et al. 2005).
NWP-3bNoneEconomic ImpactIndustry
Mytilus galloprovincialis is considered to be the most expensive fouling organism of power plants in Japanese waters, causing major expenses for damage and cleaning (Iwasaki 2006).
NZ-IVNoneEcological ImpactHybridization
Hybrid lineages between the native Southern Hemisphere lineage and the Northeast Atlantic lineage at several locations in Hauraki Gulf, near Auckland, and on the northern shore of the South Island (2000-2008, Gardner et al. 2016). The ecological effects of this introgression is unknown, but Gardner et al. regard it as threat to genetic biodiversity of native mussel populations, particulay on remote oceanic islands.
CACaliforniaEcological ImpactCompetition
In this bioregion, the native M. trossulus once was the sole mussel species. Based on field (Bodega Marine Laboratory, open coast) and lab experiments, Mytilus galloprovincialis displaces M. trossulus (Bay Mussel) and M. californianus (Sea Mussel) through interference competition (limiting movement, outfiltering, and overgrowing) with the native mussels as well as simply outgrowing them (Shinen and Morgan 2009). Physiological observations indicate that M. galloprovincialis is better adapted metabolically to warmer temperatures than M. trossulus, while M. trossulus is favored by cooler temperatures (Braby and Somero 2006; Lockwood and Somero 2011a). Mytilus trossulus is better adapted to low salinities (Lockwood and Somero 2011a). Consequently, climatic cycles such as the Pacific Decadal Oscillation and El Nino can cause cyclic fluctuations in the range, abundance, and hybridization of the two species (Braby and Somero 2006; Hilbish et al. 2010; Lockwood and Somero 2011a b)., Competition with, and nearly complete replacement of, native M. trossulus occurred in San Diego Bay, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997). See the discussion of the bioregion for details., Competition with, and nearly complete replacement of, native M. trossulus occurred in Mission Bay, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997). See the discussion of the bioregion for details., Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997). At this time, very heavy settlement of Mytilus 'edulis' occurred at the La Jolla pier, and was accompanied by a decline in recruitment of M. californianus, the native Sea Mussel (Coe 1946, cited by Carlton 1979)., Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997)., Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997)., Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997)., Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997)., Mytilus galloprovincialis continues to compete with and dominate native M. trossulus south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010). See the bioregion discussion for details., Mytilus galloprovincialis continues to compete with and dominate native M. trossulus south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010). See the bioregion discussion for details., Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997). At this time, during a very heavy settlement of Mytilus 'edulis' in Newport Bay 'everything is smothered' (Roestler, in Burch 1946, cited by Carlton 1979)., Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997)., Competition with, and nearly complete replacement of, native M. trossulus occurred in southern California waters, possibly in the 1940s (Carlton 1979; McDonald et al. 1991; Suchanek et al. 1997)., 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)., Mytilus galloprovincialis continues to compete with and dominate native M. trossulus south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010). See the bioregion discussion for details., In 1994-95, 64% of mussels at Half Moon Bay were purebred M. galloprovincialis, while 24% were M. trossulus (Rawson et al. 1999). Changing environmental conditions (declining water temperatures) due to climate cycles, have reduced the frequency of M. galloprovincialis to ~35% (Hilbish et al. 2010)., 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)., In 1994-1995, about 32% of mussels examined at Muir Beach were purebred M. galloprovincialis, while 52% were M. trossulus (Rawson et al. 1999)., In 1990-1991, ~90% of mussels sampled in Tomales Bay were M. galloprovincialis (Sarver and Foltz 1993; Suchanek et al. 1997), while only ~5-10% were M. trossulus. In 2002, 60% were M. galloprovincialis (Braby and Somero 2006). The continued dominance of the introduced mussel here, while declining in nearby estuaries (Hilbish et al. 2010), may have been a result of ongoing aquaculture operations. , Based on field (Bodega Marine Laboratory, open coast) and lab experiments, Mytilus galloprovincialis displaces M. trossulus and M. californianus through interference competition (limiting movement, outfiltering, overgrowing) with the native mussels as well as simply outgrowing them (Shinen and Morgan 2009). In 1990-1991in Bodega Bay, purebred M. galloprovincialis comprised ~10% of total mussels sampled (Sarver and Foltz 1993), but ~60% in a 1994 survey (Rawson et al. 1999) and in 2002, at 2 sites, ~30-85% (Braby and Somero 2006)., In 1994-1995, at Gualala Point and Bodega Head, purebred M. galloprovinialis comprised 42-45% of the mussels sampled, compared to 40-44% of native M. trossulus (Rawson et al. 1999). Changing environmental conditions (declining water temperatures) due to climate cycles, have probably reduced the frequency of M. galloprovincialis (Braby and Somero 2006; Hilbish et al. 2010)., In 1994-1995, purebred M. galloprovincialis comprised ~50% of the mussels sampled at Shelter Cove, compared to about ~30% for purebred M. trossulus (Rawson et al. 1999). However, the percentage decline to ~5% by 2005-2007, apparently because of lower temperatures resulting from the Pacific Decadal Oscillation, made M. galloprovincialis less competitive (Hilbish et al. 2010)., In 1994-1995, purebred M. galloprovincialis comprised ~74% of mussels sampled at Cape Mendocino, while purebred M. trossulus were 18% (Rawson et al. 1999). In 2005-2007, the frequency of M. galloprovincialis and hybrids declined from ~20-40% to about 5%. This change was attributed to lower temperatures resulting from the Pacific Decadal Oscillation (Hilbish et al. 2010)., 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).
CACaliforniaEcological ImpactHybridization
This species was first detected in molecular surveys which began in 1985 (McDonald et al. 1991). Central California is a hybrid zone for Mytilus galloprovincialis and M. trossulus. Since molecular studies began in the late 1980s and early 1990s, both species and their hybrids have coexisted but have varied in abundance with cyclic 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 (Braby and Somero 2006). The fact that most detected hybrids are first-generation (F1) suggests little genetic exchange between populations and possible genetic incompatibility (Rawson et al. 1999). In earlier surveys, the hybrid zone extended north of Cape Mendocino (McDonald et al. 1991; Sarver and Foltz 1993; Rawson et al. 1999). In 2005-2007, the frequency of M. galloprovinicalis and hybrids, north of 39°N declined from ~15-70% to about 5%. This change was attributed to lower temperatures, resulting from the Pacific Decadal Oscillation (Hilbish et al. 2010)., Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details., Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion of the bioregion for details., Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion of the bioregion for details., Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion of the bioregion for details., Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details., Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details., Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details., Extensive hybridization between Mytilus galloprovincialis with native M. trossulus continues to occur south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010)., Extensive hybridization between Mytilus galloprovincialis with native M. trossulus continues to occur south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010)., Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details., Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. See the discussion for the bioregion for details., Hybridization between M. galloprovincialis and M. trossulus was probably widespread during the early invasion and replacement of M. trossulus. In 2010, the Santata Barbara population was found to be pure M. galloprovincialis (Saarman and Pogson 2015)., 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)., Extensive hybridization between Mytilus galloprovincialis with native M. trossulus continues to occur south of Monterey Bay (McDonald et al. 1991; Hilbish et al. 2010)., ~12% of mussels examined at Half Moon Bay were hybrids (M. trossulus X M. galloprovincialis), compared to 24% purebred M. trossulus (Rawson et al. 1999)., 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., In 1994-1995, ~16% of mussels examined at Muir Beach were hybrids (M. trossulus X M. galloprovincialis) compared with 56% purebred M. trossulus (Rawson et al. 1999). Changing environmental conditions (declining water temperatures) due to climate cycles, have probably reduced the frequency of M. galloprovincialis (Braby and Somero 2006; Hilbish et al. 2010)., Mytilus galloprovincialis X M. trossulus hybrids comprised ~0-5% of total mussels sampled (Sarver and Foltz 1993), about 15% in a 1994 survey (Rawson et al. 1999) and in 2002, at 2 sites, ~10-15% (Braby and Somero 2006)., Mytilus galloprovincialis X M. trossulus hybrids comprised 14% of total mussels sampled in a 1994-1995 survey (Rawson et al. 1999)., In 1994-1995, M. galloprovincialis X M. trossulus hybrids comprised 12-20% of the mussels at Shelter Cove. In 2005-2007, the frequency of hybrids declined sharply, to about 1-2% (Hilbish et al. 2010), apparently due to lower temperatures resulting from the Pacific Decadal Oscillation, making M. galloprovincialis less competitive (Hilbish et al. 2010)., In 1994-1995, purebred M. galloprovincialis comprised ~74% of mussels sampled at Cape Mendicino, while purebred M. trossulus were 18% (Rawson et al. 1999). In 2005-2007, the frequency of M. galloprovincialis and hybrids declined from ~20-40% to about 5%. This change was attributed to lower temperatures, resulting from the Pacific Decadal Oscillation (Hilbish et al. 2010)., 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).
CACaliforniaEconomic ImpactFisheries
Mussel aquaculture has been conducted in Tomales Bay (Conte 1992; California Department of Fish and Game 2010). Websites indicate that these operations continue (http://tomalesbayoysters.com/)., Mussel (M. galloprovincialis) aquaculture has been conducted in San Diego Bay and the Santa Barbara Channel, involving growing mussels on ropes from former oil platforms (Conte 1992; California Department of Fish and Game 2010). Websites indicate that the Santa Barbara Channel operations continue (http://www.sbmariculture.com/shellfish.html)., Mussel aquaculture has been conducted in Tomales Bay (Conte 1992; California Department of Fish and Game 2010). Websites indicate that these operations continue (http://tomalesbayoysters.com/)., 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).
WAWashingtonEcological ImpactCompetition
In Puget Sound, where M. trossulus was once the sole mussel species, the frequency of M. galloprovincialis is greatest in protected waters near areas of likely introduction, including marinas, shipping harbors, and aquaculture sites, but also shallow, warmer waters favorable to the growth of the introduced mussel. At 4 of about 60 sites in this bioregion, purebred M. galloprovincialis exceeded 25% of the mussels sampled (Wonham 2004). Elliott et al. (2008), sampling more selectively in Puget Sound, found 6 of 29 sites in which frequencies of M. galloprovincialis comprised more than 25% of the sampled mussels. In most sites in Puget Sound (Wonham 2004; Sheilds et al. 2010), the abundance of M. trossulus and its hybrid are so low that competitive impacts on M. trossulus are likely to be small.
WAWashingtonEcological ImpactHybridization
Locally high rates of hybridization (10-57% of sampled mussels) between Mytilus galloprovincialis and native M. trossulus have been found in locations in Puget Sound near marinas, ports, and shellfish farms (Anderson et al. 2002; Wonham 2004, Elliott et al. 2008).
WAWashingtonEconomic ImpactFisheries
Extensive aquaculture of M. galloprovincialis is conducted in waters of British Columbia and Puget Sound (Anderson et al. 2002; Wonham 2004; Elliott et al. 2008; http://www.taylorshellfishfarms.com/ourStore-mussels-mediterranean).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NEA-III None 0 Native Estab
NEA-IV None 0 Native Estab
NEA-V None 0 Native Estab
MED-I None 0 Native Estab
MED-II None 0 Native Estab
MED-III None 0 Native Estab
MED-IV None 0 Native Estab
MED-VII None 0 Native Estab
MED-VI None 0 Native Estab
MED-IX None 0 Native Estab
NEP-VI Pt. Conception to Southern Baja California 1987 Def Estab
NEP-V Northern California to Mid Channel Islands 1987 Def Estab
NEP-IV Puget Sound to Northern California 1996 Def Estab
NEP-III Alaskan panhandle to N. of Puget Sound 1994 Def Estab
NWP-3b None 1934 Def Estab
NWP-4a None 1941 Def Estab
NWP-2 None 1983 Def Unk
WA-IV None 1979 Def Estab
AUS-IX None 2009 Def Estab
NZ-IV None 2009 Def Estab
WA-V None 1987 Def Estab
NWP-3a None 1950 Def Estab
AUS-VIII None 0 Def Estab
AUS-X None 2009 Def Unk
SP-XXI None 1998 Def Failed
P020 San Diego Bay 1987 Def Estab
P030 Mission Bay 2000 Def Estab
P022 _CDA_P022 (San Diego) 1992 Def Estab
P023 _CDA_P023 (San Louis Rey-Escondido) 2000 Def Estab
P050 San Pedro Bay 1987 Def Estab
P060 Santa Monica Bay 1990 Def Estab
P062 _CDA_P062 (Calleguas) 2000 Def Estab
P069 _CDA_P069 (Central Coastal) 1987 Def Estab
P070 Morro Bay 1992 Def Estab
P040 Newport Bay 1990 Def Estab
P064 _CDA_P064 (Ventura) 1990 Def Estab
P065 _CDA_P065 (Santa Barbara Channel) 1990 Def Estab
P080 Monterey Bay 1990 Def Estab
P073 _CDA_P073 (Central Coastal) 1995 Def Estab
P086 _CDA_P086 (San Francisco Coastal South) 1995 Def Estab
P090 San Francisco Bay 1987 Def Estab
P095 _CDA_P095 (Tomales-Drakes Bay) 1987 Def Estab
P110 Tomales Bay 1987 Def Estab
P112 _CDA_P112 (Bodega Bay) 1990 Def Estab
P114 _CDA_P114 (Gualala-Salmon) 1995 Def Estab
P116 _CDA_P116 (Big Navaro-Garcia) 1995 Def Estab
P117 _CDA_P117 (Mattole) 1995 Def Estab
P130 Humboldt Bay 1990 Def Estab
P143 _CDA_P143 (Smith) 1990 Def Unk
P170 Coos Bay 1996 Def Unk
P210 Yaquina Bay 1991 Def Unk
P284 _CDA_P284 (Hoh-Quillayute) 1996 Def Unk
P288 _CDA_P288 (Dungeness-Elwha) 1998 Def Unk
P290 Puget Sound 1994 Def Estab
P293 _CDA_P293 (Strait of Georgia) 1998 Def Estab
NWP-4b None 1979 Def Estab
P286 _CDA_P286 (Crescent-Hoko) 1998 Def Unk
P093 _CDA_P093 (San Pablo Bay) 1987 Def Estab
NWP-5 None 2004 Def Estab
NZ-VIII None 2009 Def Unk
NEA-II None 0 Native Estab
MED-X None 0 Native Estab
AUS-X None 2009 Def Estab
ANT-AR2 None 2012 Crypto Unk
P010 Tijuana Estuary 1995 Def Estab
AR-IV None 2014 Crypto Unk
AR-V None 2014 Crypto Unk
AR-III None 2012 Crypto Unk
SA-II None 2016 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude
26545 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-25 Port Hueneme Sportfishing Def 34.1481 -119.2019
26660 Suchanek et al. 1997 1992 1998-03-01 Elkhorn Slough Def 36.8398 -121.7435
26674 McDonald and Koehn 1988; McDonald et al. 1991 1987 2005-06-28 Navy - Seventh St. Def 32.6699 -117.1212
26719 Sarver and Foltz 1993) 1990 1990-01-01 Benicia Def 38.0440 -122.1624
26821 Introduced Species Study 2005 2005-11-14 San Rafael Def 37.9638 -122.4774
26992 Cohen,et al. 2002 (So Cal Exotics RAS) 2000 2000-08-30 Pilots Dock at Pier F, Los Angeles Def 33.7472 -118.2156
27067 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-28 San Dieguito Lagoon Def 32.9678 -117.2597
27175 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-25 Jacks Landing Def 34.1636 -119.2228
27247 Introduced Species Study 1990 2005-07-07 Sausalito Def 37.8565 -122.4791
27327 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-29 Marina del Rey Def 33.9722 -118.4522
27339 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-24 Watchorn Basin Def 33.7203 -118.2764
27351 Sarver and Foltz 1993) 1990 1990-01-01 Berkeley Marina Def 37.8676 -122.3172
27415 Hopkins 1986, cited by Cohen and Carlton, 1995 1986 1986-01-01 Martinez, Suisun Bay Def 38.0287 -122.1333
27433 Introduced Species Study 1992 1992-01-01 Palo Alto Yacht Club Def 37.4574 -122.1057
27561 Suchanek et al. 1997 1992 1992-01-01 Point Richmond Piers Def 37.8057 -122.4121
27820 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-25 Anacapa Isle Marina Def 34.1731 -119.2269
28061 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-28 Seaforth Landing, Mission Bay Def 32.7644 -117.2381
28223 Sarver and Foltz 1993 1990 1993-01-01 Ventura Def 34.1798 -119.2297
28324 Suchanek et al. 1997 2006 2006-07-28 Morro Bay Boat Yard Def 35.3570 -120.8492
28589 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-26 Chula Vista Boat Ramp Def 32.6211 -117.1031
28648 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-30 Rainbow Lagoon Def 33.7631 -118.1914
29190 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-29 King Harbor Def 33.8464 -118.3969
29890 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-28 Snug Harbor Marina Def 33.1478 -117.3322
30106 Sarver and Foltz 1993 1993 1992-01-01 Santa Barbara Cove Def 32.7774 -117.2484
30482 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-31 Colorado Lagoon Def 33.7711 -118.1347
32205 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-24 Island Yacht Anchorage Def 33.7728 -118.2478
32972 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-31 Long Beach Yacht Club Def 33.7536 -118.2808
33207 Sarver and Foltz 1993 1990 1990-01-01 Gaviota Def 34.4716 -120.2148
33688 Cohen, et al. 2002 (So Cal Exotics RAS) 2000 2000-08-24 Newmarks Yacht Harbor Def 33.7644 -118.2497

References

Abbott, R. Tucker (1974) American Seashells, Van Nostrand Reinhold, New York. Pp. <missing location>

Alexander, Mhairi E.; Adams, Jaimie; Dick, T. A.; Robinson, Tamara B. (2015) Forecasting invasions: resource use by mussels informs invasion patterns along the South African coast, Marine Biology 162: 2493-2500

Alexander, Mhairi E.; Raven, Hannah J.; Robinson, Tamara B. (2015) Foraging decisions of a native whelk, Trochia cingulata Linnaeus, and the effects of invasive mussels on prey choice, Journal of Experimental Marine Biology and Ecology 470: 26-33

Anderson, Anthony S.; Bilodeau, A. Lelania; Gilg, Matthew R.; Hilbish, Thomas J. (2002) Routes of introduction of the Mediterranean mussel (Mytilus galloprovincialis) to Puget Sound., Journal of Shellfish Research 21(1): 75-79

Apte, Smita ; Holland, Brenden S.; Godwin, L. Scott; Gardner, Jonathan P.A. (2000) Jumping ship: a stepping stone event mediating transfer of a non-indigenous species via a potentially unsuitable environment., Biological Invasions 2: 75-79

Araya, Juan Francisco (2015) Current status of the non-indigenous molluscs in Chile, with the first record of Otala punctata (Müller, 1774) (Gastropoda: Helicidae) in the country and new records for Cornu aspersum (Müller, 1774) and Deroceras laeve (Müller,, Journal of Natural History 49(29-30): 1731-1761

Astudillo, Juan-Carlos; Wong, Jane C. Y.; Dumont, Clement P.; Bonebrake, Timothy C.; Leung, Kenneth M. Y. (2014) Status of six non-native marine species in the coastal environment of Hong Kong, 30 years after their first record, BioInvasions Records 3(3): in press

Atalaha, Javier; Brook, Rosemary; Cahill, Patrick; Fletcher, Lauren M.; Hopkins, Grant A. (2016) It’s a wrap: encapsulation as a management tool for marine biofouling, Biofouling 32(3): 277-286

Ballasteros, M.; Madrenas, E.; Pontes, M. 2022 OPK Opisthobranquis- Doris pseudoargus (Von Rapp, 1827). https://opistobranquis.info/en/guia/nudibranchia/doridina/doridoidei/doridoidea/doris-pseudoargus/



Barroso, Cristiane Xerez; Rabay, Soraya Guimarães; Matthews-Cascon, Helena (2018) Mollusks on recruitment panels placed in an offshore harbor in tropical northeastern Brazil , Arquivos de ciencias do mar 51(1): 65-74
http://dx.doi.org/10.32360/acmar.v51i1

Belz, Carlos Eduardo; Darrigran, Gustavo; Netto,Otto Samuel Mader; Boeger, Walter A.; Ribeiro, Paulo Justiniano Junior (2012) Analysis of four dispersion vectors in inland waters: the case of the invading bivalves in South America, Journal of Shellfish Research 31(3): 777-784

Bertness, Mark D. (1999) <missing title>, Sinauer Associates, Sunderland MA. Pp. 417

Bownes, Sarah J.; McQuaid, Christopher D. (2006) Will the invasive mussel Mytilus galloprovincialis Lamarck replace the indigenous Perna perna L. on the south coast of South Africa?, Journal of Experimental Marine Biology and Ecology 338: 140-151

Braby, Caren E.; Somero, George N. (2006) Ecological gradients and relative abundance of native (Mytilus trossulus) and invasive (Mytilus galloprovincialis)) blue mussels in the California hybrid zone., Marine Biology 148: 1249-1262

Branch, George M.; Odendaal, Francois; Robinson, Tamara B. (2010) Competition and facilitation between the alien mussel Mytilus galloprovincialis and indigenous species: Moderation by wave action, Journal of Experimental Marine Biology and Ecology 383: 65-78

Branch, George M.; Odendaal, Francois; Robinson, Tamara B. (2008) Long-term monitoring of the arrival, expansion and effects of the alien mussel Mytilus galloprovincialis relative to wave action, Marine Ecology Progress Series 370: 171-183

Branch, George M.; Steffani, C. Nina (2004) Can we predict the effects of alien species? A case-history of the invasion of South Africa by Mytilus galloprovincialis (Lamarck), Journal of Experimental Marine Biology and Ecology 300: 189-215

Brannock, Pamela M.; Hilbish, Thomas J. (2010) Hybridization results in high levels of sterility and restricted introgression between invasive and endemic marine blue mussels, Marine Ecological Progress Series 406: 161-171

Brothers, N. Davis G. (2008) Two records of marine mussels (Mytilidae) from subantarctic Macquairie Island, Molluscan Research Molluscan Research 28(2): 142-144

Buschbaum, Christian and 8 authors (2009) Mytilid mussels: global habitat engineers in coastal sediments, Helgoland Marine Research Published online: <missing location>

Byrnes, Jarrett; Stachowicz, John J. (2009) Short and long term consequences of increases in exotic species richness on water filtration by marine invertebrates, Ecology Letters 12: 830-841

Caceres-Martinez, Jorge & Figueras, Antonio (1998) Distribution and abundance of mussel (Mytilus galloprovincialis Lmk) larvae and post-larvae in the Ria de Vigo (NW Spain), Journal of Experimental Marine Biology and Ecology 229: 277-287

Calder, Dale R. (2019) On a collection of hydroids (Cnidaria, Hydrozoa) from the southwest coast of Florida, USA, Zootaxa 4689(1): 1-141

California Department of Fish and Game- Marine Region (2010) Status of the fisheries report- an update through 2008:, California Department of Fish and Game- Marine Region, Sacramento. Pp. 20-1-10

California Department of Health Services (2007) <missing title>, California Department of Health Services, Sacramento CA. Pp. <missing location>

Calvo-Ugarteburu, G., McQuaid, C. D. (1998) Parasitism and invasive species: effects of digenetic trematodes on mussels, Marine Ecology Progress Series 169: 149-163

Carlton, James T. (1979) History, biogeography, and ecology of the introduced marine and estuarine invertebrates of the Pacific Coast of North America., Ph.D. dissertation, University of California, Davis. Pp. 1-904

Carlton, James T. (Ed.) (2007) The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon Fourth Edition, Completely Revised and Expanded, University of California Press, Berkeley. Pp. <missing location>

Chavanich, S.; Tan, L. T.; Vallejo, B.; Viyakarn, V. (2010) Report on the current status of marine non-indigenous species in the Western Pacific region, Intergovernmental Oceanographic Commission, Subcommission for the Western Pacific, Bangkok, Thailand. Pp. 1-61

Coan, Eugene V.; Valentich-Scott, Paul (2007) The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon, University of California Press, Berkeley CA. Pp. 807-859

Coan, Eugene V.; Valentich-Scott, Paul; Bernard, Frank R. (2000) Bivalve Seashells of Western North Ameira, Santa Barbara Museum of Natural history, Santa Barbara CA. Pp. <missing location>

Cohen, Andrew N. and 12 authors (2002) Project report for the Southern California exotics expedition 2000: a rapid assessment survey of exotic species in sheltered coastal waters., In: (Eds.) . , Sacramento CA. Pp. 1-23

Cohen, Andrew N.; Carlton, James T. (1995) Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of the San Francisco Bay and Delta, U.S. Fish and Wildlife Service and National Sea Grant College Program (Connecticut Sea Grant), Washington DC, Silver Spring MD.. Pp. <missing location>

Colgan, Donald J.; Middlefart, Peter (2011) Mytilus DNA haplotypes in southeast Australia, Aquatic Biology 12: 47-53

Conte, Fred S. (1992) <missing title>, Department of Animal Science, University of California, Davis, Davis CA. Pp. 1-10

Curiel-Ramirez, Sergio; Caceres-Martinez, Jorge (2004) Reproductive cycle of coexisting mussels, Mytilus californianus and Mytilus galloprovincialis, Baja California, Mexico, Journal of Shellfish Research 23(2): 515-520

Daga, Vanessa; Debona, Salete; Abilhoa, Tiago; Gubiani, Vinícius; Éder, Simões; Vitule, André; Ricardo, Jean (2016) Non-native fish invasions of a Neotropical ecoregion with high endemism: a review of the Iguaçu River, Aquatic Invasions 11(2): 209-223
DOI: http://dx.doi.org/10.3391/ai.2016.11.2.10

Daguin, Claire; Borsa, Philippe (2000) Genetic relationships of Mytilus galloprovincialis Lamarck populations worldwide: evidence from nuclear-DNA markers, In: Harper, E. M.; Taylor, J. D.; Crome, J. A.(Eds.) The evolutionary biology of the Bivalvia. , <missing place>. Pp. 389-397

Dijkstra, Jennifer A.; Simkanin, Christina (2016) Intraspecific response of colonial ascidians to variable salinity stress in an era of global change, Marine Ecology Progress Series 551: 215-225,

Elliott, Joel; Holmes, Kathleen; Chambers, Rachel; Leon, Kate; Wimberger, Peter (2008) Differences in morphology and habitat use among the native mussel Mytilus trossulus, the non-native M. galloprovincialis,and their hybrids in Puget Sound, Washington., Marine Biology 156: 39-53

Feis, Marieke E.; Gottschalck, Leo; Ruf, Lena C.; Theising, Franziska; Demann, Felicitas; Wegner, K. Mathias (2022) Invading the occupied niche: ow a parasitic copepod of introduced oysters can expel a congener from native mussels, Frontiers in Marine Science 9( 915841): Published online
doi: 10.3389/fmars.2022.915841

Fisheries and Oceans Canada 2018b Haplosporidium costale (SSO) of Oysters. https://www.dfo-mpo.gc.ca/science/aah-saa/diseases-maladies/hcoy-eng.html



Foltz, D.W.; Sarver, S.K.; Hrincevich, A.W. (1995) Genetic structure of brackish water clams (Rangia spp.), Biochemical Systematics and Ecology 23(3): 223-233

Gardner, Jonathan P. A.; Westfall, Kristen M. (2012) Geographic distribution and molecular identification of a metapopulation of blue mussels (genus Mytilus) in northeastern New Zealand, Journal of Molluscan Studies 78: 66-73

Geller, J. B. (1999) Decline of a native mussel masked by sibling species invasion, Conservation Biology 13: 661-664

Geller, Jonathan B., Carlton, James T., Powers, Dennis A. (1994) PCR-based detection of mtDNA haplotypes of native and invading mussels on the northeastern Pacific coast: latitudinal pattern of invasion, Marine Biology 119(2): 243-249

Geller, Jonathan B.; Darling, John A.; Carlton, James T. (2010) Genetic perspectives on marine biological invasions, Annual Review of Marine Science 2: 367-393

Gestoso, Ignacio; Arenas, Francisco; Olabarria, Celia (2015) Ecological interactions modulate responses of two intertidal mussel species to changes in temperature and pH, Journal of Experimental Marine Biology and Ecology 474: 116-125

Griffiths, C. L., Hockey, P. A. R., van Erkom Schurink, C., le Roux, P. J. (1992) Marine invasive aliens on South African shores: implications for community structure and trophic functioning, South African Journal of Marine Science 12: 713-722

Harris, Larry G.; Shure, Alex; Kuzirian, Alan; Gosliner, Terrence M.; Donodoo, Samantha A. (2023) A European nudibranch new to the Gulf of Maine: Doris pseudoargus Rapp, 1827, Biological Invasions 25(2): 339-350
https://doi.org/10.1007/s10530-022-02917-0

Haupt, T. M.; Griffiths, C. L.; Robinson, T. B.;Tonin, A. F. G. (2010) Oysters as vectors of marine aliens, with notes on four introduced species associated with oyster farming in South Africa, African Zoology 45: 52-62

Heath, David D..; Rawson, Paul D.; Hilbish, Thomas J. (1995) PCR-based nuclear markers identify alien blue mussel (Mytilus spp.) genotypes on the west coast of Canada, Canadian Journal of Fisheries and Aquatic Science 52: 2621-2627

Hilbish, T. J.; Mullinax, A.; Dolven, S. I.; Meyer, A.; Koehn, R. K.; Rawson, P. D. (2000) Origin of the antitropical distribution pattern in marine mussels (Mytilus spp.): Routes and timing of transequatorial migration, Marine Biology 136: 69-77

Hilbish, Thomas J.; Brannock, Pamela M.; Jones, Karlie R.; Smith, Allison B.; Bullock, Brooke N.. Wethey, David E. (2010) Historical changes in the distributions of invasive and endemic marine invertebrates are contrary to global warming predictions: the effects of decadal climate oscillations, Journal of Biogeography 37: 423-431

His, E.; Robert, R.; Dinet, A. (1989) Combined effects of temperature and salinity on fed and starved larvae of the Mediterranean mussel Mytilus galloprovincialis and the Japanese oyster Crassostrea gigas, Marine Biology 100: 455-463

Hockey, P. A. R. ; Van Erkom Schurink (1992) The invasive biology of the mussel of the Southern African coast, Transactions of the Royal Society of South Africa 48(1): 123-139

Hooper, J. N. A.; Van Soest, S. I. 2024 World Porifera Databse. https://www.marinespecies.org/porifera/index.php



Inoue, K. and 8 authors (1997) A possible hybrid zone in the Mytilus edulis complex in Japan revealed by PCR markers, Marine Biology 128: 91-95

Iwasaki, Keiji (2006) Assessment and Control of Biological Invasion Risks., Shoukadoh Book Sellers,and IUCN, Kyoto and Gland, Switzerland. Pp. 104-112

Kijewski, T. and 5 authors (2011) Distribution of Mytilus taxa in European waters as inferred from molecular markers, Journal of Sea Research 65: 224-234

Kim, Daemin; Taylor, Andrew T.; Near, Thomas J. (2022) Phylogenomics and species delimitation of the economically important Black Basses (Micropterus), Scientific Reports 12(9113): Published online
https://doi.org/10.1038/s41598-022-11743-2

Kuo, John; Shibuno, Takuro; Kanamoto, Ziyusei; Noro, Tadahide (2001) Halophila ovalis (R. Br.) Hook. f. from a submarine hot spring in southern Japan, Aquatic Botany 70(70): 329-335

Kurihara, Takeo; Kosuge, Takeharu; Takami, Hideki; Iseda, Masatsugu, Iseda; Matsubara, Kei (2009) Evidence of a sharper decrease in a non-indigenous mussel Mytilus galloprovincialis than in indigenous bivalves from 1978 to 2006 on Japanese rocky shores, Biological Invasions 12: 2671-2681

Lee, Jun-Sang; Lee, Yong Seok; Min, Duk-Ki (2010) Introduced molluscan species to Korea, Korean Journal of Malacology Molluscan Research 26(1): 45-49

Lee, S. Y., Morton, B. (1985) The introduction of the Mediterranean mussel Mytilus galloprovincialis into Hong Kong, Malacological Review 18(1-2): 107-109

Li, Xinzhengl Shenz. Anglv; Xu, zhaou (2008) Report on some shrimos from dontou Island, Zhejiang, China (Decapoda, Natantia, Crustaceana (Leiden) <missing volume>: <missing location>

Linsmayer, Lauren, (2011) <missing title>, Stanford University, Stanford CA. Pp. 48 pp.

Lockwood, Brent L.; Somero, George N. (2012) Functional determinants of temperature adaptation in enzymes of cold- versus warm-adapted mussels (genus Mytilus), Molecular Biology and Evolution 29(10): 3061-3070

Lockwood, Brent L.; Somero, George N. (2011) Transcriptomic responses to salinity stress in invasive and native blue mussels (genus Mytilus), Molecular Ecology 20: 517-529

Lockwood, Brent L.; Somero, George N. (2011) Invasive and native blue mussels (genus Mytilus) on the California coast: The role of physiology in a biological invasion, Journal of Experimental Marine Biology and Ecology 400: 167-174

Lopez-Duarte, Paola C.; Carson, Henry S.; Cook, Geoffrey S.; Fodrie, F. Joel; Becker, Bonnie J.; DiBacco, Claudio; Levin, Lisa A. (2012) What controls connectivity? An empirical, multi-species approach, Integrative and Comparative Biology 52(4): 511-524

Low-Pfeng, Antonio; Recagno, Edward M. Peters (2012) <missing title>, Geomare, A. C., INESEMARNAT, Mexico. Pp. 236

Lutaenko, Konstantin A.; Furota,Toshio; Nakayama, Satoko; Shin, Kyoungsoon; Xu, Jing (2013) <missing title>, Northwest Pacific Action Plan- Data and Information Network Regional Activity Center, Beijing, China. Pp. <missing location>

Lutaenko, Konstantin A.; Je, Jong-Geel; Shin, Sang-Ho (2006) Bivalve mollusks in Yeongiul Bay, Korea 2. Faunal analysis, Korean Journal of Malacology Molluscan Research 22: 63-86

Ma, Kevin C. K.;; Gusha, Molline N. C.;; Zardi, Gerardo; Nicastro, Katy R.; Monsinjon; Jonathan R.; McQuaid, Christopher D. (2021) Biogeographic drivers of distribution and abundance in an alien ecosystem engineer: Transboundary range expansion, barriers to spread, and spatial structure, Journal of Biogeography Published online: <missing location>

Marquet, Nathalie and 6 authors (2012) Comparison of phototrophic shell-degrading endoliths in invasive and native populations of the intertidal mussel Mytilus galloprovincialis, Biological Invasions published online: <missing location>

Marraffini, M. L.; Geller, J. B. (2015) Species richness and interacting factors control invasibility of a marine community, Proceedings of the Royal Society of London B 282: Published online

Matsumasa, Masatoshi; Hamaguchi, Masami; Nishihira, Moritaka (1999) Morphometric characteristics and length of the ‘variable region’ in the nonrepetitive domain of the adhesive protein of Mytilus species in the Asamushi area, northern Japan, Zoological Science 16(6): 985-991

McDonald, J. H.; Koehn, R. K. (1988) The mussels Mytilus galloprovincialis and M. trossulus on the Pacific coast of North America., Marine Biology 99: 111-118

McDonald, J. H.; Seed, R.; Koehn, R. K. (1991) Allozymes and morphometric characters of three species of Mytilus in the Northern and Southern Hemispheres., Marine Biology 111(3): 323-334

McKindsey, Christopher W.; Archambault, Philippe; Callier, Myriam D.; Olivier, Frédéric (2011) Influence of suspended and off-bottom mussel culture on the sea bottom and benthic habitats: a review, Canadian Journal of Fisheries and Aquatic Science 89: 622-646

McQuaid, C. D.; Phillips, T. E. (2002) Limited wind-driven dispersal of intertidal mussel larvae: in situ evidence from the plankton and the spread of the invasive species Mytilus galloprovincialis in South America, Marine Ecology Progress Series 201: 211-220

Mead, A.; Carlton, J. T.; Griffiths, C. L. Rius, M. (2011b) Introduced and cryptogenic marine and estuarine species of South Africa, Journal of Natural History 39-40: 2463-2524

Moore, Kenneth A. (2009) Submerged Aquatic Vegetation of the York River, Journal of Coastal Research 37(SI): 50-56

Morton, Brian (1987) Recent marine introductions into Hong Kong, Bulletin of Marine Science 41(2): 503-513

Murray, Cathryn Clarke; Therriault, Thomas W.; Martone, Patrick T. (2012) Adapted for invasion? Comparing attachment, drag and dislodgment of native and nonindigenous hull fouling species, Biological Invasions <missing volume>: published online

Nguyen, Vy X.; Detcharoen, Matsapume; Tuntiprapas, Piyalap; Soe-Htun, U Japar; Sidik, B; Harah, Muta Z; Prathep, Anchana; Papenbrock, Jutta (2014) Genetic species identification and population structure of Halophila (Hydrocharitaceae) from the Western Pacific to the Eastern Indian Ocean, BMC Evolutionary Biology 14(92): Published online

Nicastro, K. R.; Zardi, G. I.; McQuaid, C. D. (2008) Movement behaviour and mortality in invasive and indigenous mussels: resilience and resistance strategies at different spatial scales., Marine Ecological Progress Series 372: 119-126

Nicastro, K. R.; Zardi, G. I.; McQuaid, C. D. (2007) Behavioural response of invasive Mytilus galloprovincialis and indigenous Perna perna mussels exposed to risk of predation., Marine Ecology Progress Series 336: 169-175

Nicastro, K. R.; Zardi, G. I.; McQuaid, C. D. (2010) Differential reproductive investment, attachment strength and mortality of invasive and indigenous mussels across heterogeneous environments, Biological Invasions 12: 2165-2177

Nicastro, Katy R. and 5 authors Gregory L Blatch and 5 authors (2010) The role of gaping behaviour in habitat partitioning between coexisting intertidal mussels, BMC Ecology 10(17): 1-11

Novoa, Anai; Theresa S. Talley, Drew M.; Crooks, Jeffrey A.; Reyns, Nathalie B. (2016) Spatial and temporal examination of bivalve communities in several estuaries of southern California and northern Baja California, MX, PLOS ONE 11(2): e0148220.

Okamura, Beth (1986) Formation and disruption of aggregations of Mytilus edulis in the fouling community of San Francisco Bay, California, Marine Ecology Progress Series 30: 275-282

Ouagajjou, Yassine; Presa, Pablo; Astorga, Marcela; Pérez, Montse (2011) Microsatellites of Mytilus chilensis: A genomic print of Its taxonomic status within Mytilus sp., Journal of Shellfish Research 30(2): 325-330

Oyarzun, Pablo A.; Toro, Jorge E.; Canete, Juan I.; Gardner, Jonathan P. (2016) Bioinvasion threatens the genetic integrity of native diversity and a natural hybrid zone: smooth-shelled blue mussels (Mytilus spp.) in the Strait of Magellan, Biological Journal of the Linnean Society 117: 574-585

Page, Henry M.; Zaleski, Susan F; Miller , Robert J ; Dugan, Jenifer E Schroeder, Donna M ; Doheny, Brandon (2019) Regional patterns in shallow water invertebrate assemblages on offshore oil and gas platforms along the Pacific continental shelf, Bulletin of Marine Science 95(4): 617-638

Pearce, Fred (2/7/2013) Invasive mussel poses ecological and economic threat to island community, The Guardian published online: <missing location>

Pernecker , Balint; Czirok, Attila; Mauchart, Peter; Boda, Pal; Mora, Arnold Zoltan, Csabai. (2021) No experimental evidence for .vector-free, long-range, upstream dispersal of adult Asian clams [Corbicula fluminea, Biological Invasions 23: 1425-1441

Pister, Benjamin (2009) Urban marine ecology in southern California: the ability of riprap structures to serve as rocky intertidal habitat, Marine Biology 156: 861-873

Rawson, P. D., Agrawal, V., Hilbish, T. J. (1999) Hybridization between the blue mussels Mytilus galloprovincialis and M. trossulus along the Pacific coast of North America: evidence for limited introgression., Marine Biology 134: 201-211

Rawson, Paul D.; Hayhurst, Susan. Vanscoyoc, Brook (2001) Species composition of blue mussel populations in the northwestern Gulf of Maine, Journal of Shellfish Research 20(1): 31-38

Reaugh-Flower, Kathleen E. and 6 authors (2010) Patterns of mussel recruitment in southern Africa: a caution about using artificial substrata to approximate natural recruitment, Marine Biology 157: 2177-2185

Richoux, N. B.; Levings, C. D.; Lu, L.; Piercey, G. E. (2006) Preliminary survey of indigenous, non-indigenous and cryptogenic benthic invertebrates in Burrard Inlet, Vancover, British Columbia, Canadian Data Report of Fisheries and Aquatic Sciences 1183: 1-20

Rius, Marc; McQuaid, Christopher D. (2009) Faciltiation and competition between invasive and indigenous mussels over a gradient oif physical stress, Basic and Applied Ecology 10: 607-613

Robinson, T. B.; Griffiths, C. L.; Branch, G. M. Govender, A. (2007) The invasion and subsequent die-off of Mytilus galloprovincialis in Langebaan Lagoon, South Africa: effects on natural communities., Marine Biology 152: 225-232

Robinson, T. B.; Griffiths, C. L.; Kruger, N. (2004) Distribution and status of marine invasive species in and bordering the West Coast National Park., Koedoe 47: 79-87

Robinson, T. B.; Griffiths, C. L.; McQuaid, C. D.; Rius, M. (2005) Marine alien species of South Africa-- status and impacts, African Journal of Marine Science 27(1): 297-306

Robinson, Tamara B.; Branch, George M.; Griffiths, Charles L.; Govender, Anesh; Hockey, Philip A. R. (2007) Changes in South African rocky intertidal invertebrate community structure associated with the invasion of the mussel Mytilus galloprovincialis, Marine Ecology Progress Series 340: 163-171

Rogers, Tanya L.; Byrnes, Jarrett E.; Stachowicz, John J. (2016) Native predators limit invasion of benthic invertebrate communities in Bodega Harbor, California, USA, Marine Ecology Progress Series 545: 161-173

Saarman, Norah P.; Pogson, Grant H. (2015) Introgression between invasive and native blue mussels (genus Mytilus) in the central California hybrid zone, Molecular Ecology 24: 4723-4738

Sadchatheeswaran, Saachi; Branch, George M.; Robinson, Tamara B. (2015) Changes in habitat complexity resulting from sequential invasions of a rocky shore: implications for community structure, Biological Invasions 17: 1799-1816

Sarver, S. K.; Foltz, D. W. (1993) Genetic population structure of a species' complex of blue mussels (Mytilus spp.), Marine Biology 117: 105-112

Satuito, C. G. (1994) Larval development of the mussel Mytilus edulis galloprovincialis cultured under laboratory conditions., Fisheries Science 60(1): 65-68

Savoya, Verónica; Otero, Julieta Gómez; Schwindt, Evangelina (2015) Toward a better understanding of the native/nonnative status of Mytilus mussels in the southwestern Atlantic: Comparing pre-European middens and modern populations, Journal of Coastal Research 31(3): 742-748

Schneider, Kimberly R. (2008) Heat stress in the intertidal: Comparing survival and growth of an invasive and native mussel under a variety of thermal conditions., Biological Bulletin 215: 253-264

Sebastian Ruiz, C. ; Steffani, C. N.; Branch, G. M. (2002) Homing and movement patterns of a south African limpet Scutellastra argenvillei in an area invaded by an alien mussel Mytilus galloprovinvialis, Marine Ecology Progress Series 243: 111-122

Seed, R. (1969) The ecology of Mytilus edulis l. (Lamellibranchiata) on exposed rocky shores II. growth and mortality, Oecologia 3: 317-350

Semenikhina, Olga Ya.; Kolotukhina, Natalya K.; Evseev, George A. (2008) Morphology of larvae of the family Mytilidae (Bivalvia) from the north-western part of the Sea of Japan, Journal of the Marine Biological Association of the United Kingdom 88(2): 331-339

Shields, J. L.; Heath, J. W.; Heath, D. D. (2010) Marine landscape shapes hybrid zone in a broadcast spawning bivalve: introgression and genetic structure in Canadian west coast Mytilus, Marine Ecology Progress Series 399: 211-223

Shields, Jody L.; Barnes, Penny; Heath, Daniel D. (2008) Growth and survival differences among native, introduced and hybrid blue mussels (Mytilus spp.): genotype, environment and interaction effects., Marine Biology 154: 919-928

Shinen, J. S.; Morgan, S. G. (2009) Mechanisms of invasion resistance: competition among intertidal mussels promotes establishment of invasive species and displacement of native species, Marine Ecology Progress Series 383: 187-197

Shurova, N. M. (2001) Influence of salinity on the structure and the state of bivalve Mytilus galloprovincialis populations, Russian Journal of Marine Biology 27(3): 151-155.

Siegert, Nathan W. McCullough, Deborah G. Liebhold, Andrew M. Telewski, Frank W. (2014) Dendrochronological reconstruction of the epicentre and early spread of emerald ash borer in North America, Diversity and Distributions 20: 847–858

Skurikhina, L. A.; Katavtsev, Yu. F.; Chicvarkhin, A. Yu.; Pan'kova, M. V. (2004) Study of two species of mussels, Mytilus trossulusand Mytilus galloprovincialis and their hybrids in Peter the Great Bay of the Sea of Japan with the use of PCR markers., Russian Journal of Genetics 37(12): 1448-1451

Smietanka, B.; Zbawicka, M.; Wolowicz, M.; Wenne, R. (2004) Mitochondrial DNA lineages in the European populations of mussels (Mytilus spp.), Marine Biology 146: 79-92

Soors, Jan; Faasse, Marco; Stevens, Maarten; Verbessem, Ingrid; De Regge, Nico;Van den Bergh, Ericia (2010) New crustacean invaders in the Schelde estuary (Belgium), Belgian Journal of Zoology 140: 3-10

Suchanek, T. H., Geller, J. B., Kreiser, B. R., Mitton, J. B. (1997) Zoogeographic distribution of the sibling species Mytilus galloprovincialisand M. trossulus(Bivalvia: Mytilidae) and their hybrids in the North Pacific, Biological Bulletin 193: 187-194

Sylvester, Francisco and 8 authors (2011) Hull fouling as an invasion vector: can simple models explain a complex problem?, Journal of Applied Ecology 48: 415-423

Tagliarolo, Morgana; McQuaid, Christopher D. (2015) Sub-lethal and sub-specific temperature effects are better predictors of mussel distribution than thermal tolerance, Marine Ecology Progress Series 535: 145-159

Turon, Xavier; Tarjuelo, Isabel; Duran, Sandra; Pascual, Marta (2003) Characterising invasion processes with genetic data: an Atlantic clade of Clavelina lepadiformis (Ascidiacea) introduced into Mediterranean harbours, Hydrobiologia 503: 29-35

Westfall, Kristen M.; Gardner, Jonathan P. A. (2010) Genetic diversity of Southern hemisphere blue mussels (Bivalvia: Mytilidae) and the identification of non-indigenous taxa, Biological Journal of the Linnean Society 101: 898-909

Westfall, Kristen M.; Gardner, Jonathan P. A. (2013) Interlineage Mytilus galloprovincialis Lmk. 1819 hybridization yields inconsistent genetic outcomes in the Southern hemisphere, Biological Invasions published online: <missing location>

Wijsman, J.W.M.; Smaal, A.C. (2006) <missing title>, Wageningen IMARES (Institute for Marine Resources & Ecosystem Studies), Jmuiden, Yeserke, Texel. Pp. <missing location>

Wilkins, N. P., Fujino, K., Gosling, E. M. (1983) The mediterranean mussel Mytilus galloprovincialis Lmk. in Japan, Biological Journal of the Linnean Society 20: 365-374

Wonham, Marjorie J. (2000) Factor limiting mussel invasion, In: Pederson, Judith(Eds.) Marine Bioinvasions. , Cambridge. Pp. 127-129

Wonham, Marjorie J. (2004) Mini-review: distribution of the Mediterranean mussel Mytilus galloprovincialis (Bivalvia: Mytilidae and hybrids in the Northeast Pacific., Journal of Shellfish Research 23(2): 535-543

Woods Hole Oceanographic Institution, United States Navy Dept. Bureau of Ships (1952) Marine fouling and its prevention., United States Naval Institute., Washington, D.C.. Pp. 165-206

Zardi, G. I.; McQuaid, C. D.; Nicastro, K. R. (2007) Balancing survival and reproduction: seasonality of wave action, attachment strength and reproductive output in indigenous Perna perna and invasive Mytilus galloprovincialis mussels., Marine Ecology Progress Series 334: 155-163

Zardi, G. I.; McQuaid, C. D.; Teske, P. R.; Barker, N. P. (2007) Unexpected genetic structure of mussel population in South Africa: indigenous Perna perna and invasive Mytilus galloprovincialis., Marine Ecology Progress Series 337: 135-144

Zardi, G. I.; Nicastro, K. R.; Porri, F.; McQuaid, C. D. (2006) Sand stress as a non-determinant of habitat segregation of indigenous (Perna perna) and invasive (Mytilus galloprovincialis) mussels in South Africa., Marine Biology 148: 1031-1038

Zbawicka, Malgorazata; Wenne, Roman; Dias, Patricia Joana; Gardenr, Jonathan P. A. (2022) Combined threats to native smooth-shelled mussels (genus Mytilus) in Australia: bioinvasions and hybridization, Zoological Journal of the Linnean Society 194: 1194-2011

Zvyaginstev, A. Yu.; Radashevsky, V. I.; Ivin, V. V.; Kashin, I. A.; Gorodkov, A. N. (2011) Nonindigenous species in the far-eastern seas of Russia, Russian Journal of Biological Invasions 2(1): 164-182