Invasion History

First Non-native North American Tidal Record: 1924
First Non-native West Coast Tidal Record: 1924
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Venerupis philippinarum has a wide native range, from the southern Kuril and Sakhalin Islands, Russia (Golikov et al. 1976) to India, Sri Lanka, and the Philippines (Huang 2001; Academy of Natural Sciences of Philadelphia 2006; Mao et al. 2011). It was introduced to Hawaii as a food animal in 1918 (Carlton and Eldredge 2009), but reached the West Coast of North America (Samish Bay, Washington) with plantings of Pacific Oysters (Crassostrea gigas) (Carlton 1979), and was then widely introduced from British Columbia to California as a popular seafood item (Carl and Giguet 1972; Cohen and Carlton 1995). It was introduced to northern France in 1974, and is established from Ireland and the Netherlands, to Spain, Greece, and Turkey (Cigarria et al. 1997; Goulletquer et al. 2002; Zenetos et al. 2002; Drummond et al. 2006). It is now widely and often intensively farmed, as well as being recreationally harvested, in its native and introduced range (Food and Agricultural Organization 2013).

North American Invasion History:

Invasion History on the West Coast:

Venerupis philippinarum was first reported in the Northeastern Pacific in Samish Bay, Washington (WA) in 1924, in areas where Pacific Oysters had been planted (Kincaid 1947, cited by Carlton 1979). It began to spread along the coast to the north and south, reaching Ladysmith, on the east coast of Vancouver Island, British Columbia by 1936, and spreading up the Strait of Georgia in the 1940s and 1950s. The Japanese Littleneck also spread up the west coast of Vancouver Island, colonizing Barkley Sound and Esperanza Inlet in the 1950s, reaching Quatsino Island near the north end of the island before 1971 (Carl and Guiguet 1972; Carlton 1979). In 1972, it was found on Spider Island, in southern Queen Charlotte Sound (Carlton 1979, 50°50'N). In a 2006 survey, it was found at Princess Royal Island, further north in Queen Charlotte Sound (53°N, Gillespie et al. 2007), its current northern limit. This spread appears to be mostly due to the movement of planktonic larvae by currents, but aided also by oyster plantings.

To the south, V. philippinarum was reported in Puget Sound in 1943 (Eyerdam 1943, cited by Carlton 1979; Cohen et al. 1998), Willapa Bay in 1947, and San Francisco Bay in 1947 (Carlton 1979; Cohen and Carlton 1995). It was discovered later at several intermediate sites, including the San Juan Islands in 1950, Grays Harbor in 1964, and Humboldt Bay in 1964. These records may not represent dispersal, but instead recognition of clams introduced with earlier plantings of Pacific Oysters (Carlton 1979). Venerupis philippinarum may have been easily overlooked, owing to its similarity to the native Pacific Littleneck (Leukoma staminea) (Abbott 1974; Cohen 2005; Coan and Valentich-Scott, in Carlton 2007). Once this clam was recognized as a desirable shellfish, state fish and game agencies, and probably private individuals, as well, began stocking it in West Coast estuaries. Stocking attempts occurred in Oregon at Netarts, Tillamook, Yaquina, and Coos Bays, but established populations occur only in Netarts Bay (Carlton 1979; Carlton 1989; Wonham and Carlton 2005). In smaller estuaries in California, including Bodega Harbor, Estero Americano, and Elkhorn Slough, V. philippinarum was discovered between 1949 and 1977, probably spreading with oyster transplants, natural dispersal, and possibly unofficial plantings. Deliberate plantings were made by the California Fish and Game Department in Morro Bay, Newport Bay, and the Salton Sea (a desert salt lake) from 1953 to 1967, but these were all unsuccessful (Carlton 1979). However, in 1998 and 2000 surveys, V. philippinarum was found in several southern California estuaries, including Port Hueneme, Los Angeles-Long Beach Harbors, and Newport Bay (Fairey et al. 2002; Ranasinghe et al. 2005). In 2009, it was the dominant bivalve in Colorado Lagoon, a small estuary in Long Beach, CA (Burnaford et al. 2011). By 2013, it was abundant in Mission Bay, San Diego (Talley et al. 2015). The Japanese Littleneck was reported in Bahía de San Quintín, Baja California, Mexico in 1987 (Cohen 2005).

Invasion History in Hawaii:

Venerupis philippinarum may have been introduced in Pearl Harbor by a Japanese immigrant in the 1880s or 1890s, but the first documented collections were made in 1918 (Carlton and Eldredge 2009). In 1920 it was introduced to Kaneohe Bay and Kahili Basin (Yap 1977; Coles et al. 2002; Carlton and Eldredge 2009). It was later introduced to Molokai, Kauai; Maui; Lanai; and Hawaii (Brock 1960; Carlton and Eldredge 2009). Some of these populations have been eliminated, reduced, or restricted by heavy human harvesting and native predators (Carlton and Eldredge 2009).

Invasion History Elsewhere in the World:

In Europe, several batches of 400 to 500,000 V. philippinarum from Puget Sound were imported into France under supervision by the Institute Scientifique des Peches Maritimes in 1972. They were raised, bred, and released in 1973-1974 to waters in Normandy, along the English Channel (Flaasch and Leborgne 1992; Goulletquer et al. 2002). The success of these introductions, led to culture and planting of these 'Manila Clams' in British waters, beginning in 1980. Initially, it was believed that there would be no recruitment in UK waters, due to low water temperatures (Utting and Spencer 1992). However, a population introduced in Poole Harbour, off the English Channel, in 1988, became established (Jensen et al. 2004; Humphreys et al. 2007; Herbert et al. 2012). On the west coast of Ireland and southern Norway, the clam is cultured, but successful recruitment has not been observed (Mortensen et al. 2000; Drummond et al. 2006). As a result of successful cultivation and establishment of V. philippinarum in northern France, by the 1980s, it was introduced in Atlantic Spain (Cigarria et al. 1997), and in the Thau Lagoon, on the Mediterranean coast of France (Zenetos et al. 2003). In 1983, cultivation began in the Lagoon of Venice and soon the lagoons of the northern Adriatic became the dominant region for commercial production of the bivalve (Breber 2002; Crocetta 2012; Sladonja et al. 2011). It is also established in the Sea of Marmara, Turkey, the adjacent Aegean Sea (Cinar et al. 2005; Albayrak 2011), and lagoons on the Tyrrhenian and Ionian coasts of Italy (Crocetta 2012).

Venerupis philippinarum has been introduced to Tahiti and Fiji (Eldredge 1994; US National Museum of Natural History 2007), but the success of these introductions is not known.


Description

Ruditapes philippinarum ias been known, especially in North America, as Venerupis philippinarum, and frequently by the older names Tapes philippinarum, or Tapes japonica. This clam's shape is roughly oval, with a moderate beak located anterior of the midline. The exterior of the shell is sculptured with concentric lines and radial ribs, with beadlike nodes at their intersections. The ribs are somewhat stronger in the center of the shell. The inner ventral margin is smooth. The hinges of the two valves are very similar. The ligament is elevated above the dorsal margin. The lunule is heart-shaped. The two siphons are separate at the tips. The color of the shell is highly variable, but the shell is often predominantly cream-colored or gray. It is often variegated, with concentric brown lines, or angular patches. Specimens from anoxic mud are sometimes completely black. The interior margins are deep purple, while the center of the shell is pearly white, and smooth. The pallial sinus is often stained with yellow. The clam reaches 40 to 57 mm in length and in rare instances to 79 mm. Description from: Abbott 1974; Cohen 2005; Coan et al. 2000; Coan and Valentich-Scott, in Carlton 2007; Gillespie et al. 2012.


Taxonomy

Taxonomic Tree

Kingdom:   Animalia
Phylum:   Mollusca
Class:   Bivalvia
Subclass:   Heterodonta
Order:   Veneroida
Superfamily:   Veneroidea
Family:   Veneridae
Species:   philippinarum

Synonyms

Paphia bifurcata (Quayle, 1938)
Ruditapes philipinarum ((dams and Reeve), 1850)
Tapes denticuata (Sowerby, 1852)
Tapes ducalis (Römer, 1870)
Tapes indica (Sowerby, 1852)
Tapes japonica (Deshayes, 1853)
Tapes philipinarum (Adams and Reeve, 1850)
Tapes semidecussatata (Reeve, 1864)
Tapes violascens (Deshayes, 1854)
Venerupis philippinarum ((Adams and Reeve), 1850)

Potentially Misidentified Species

Leukoma staminea
Pacific Littleneck, NE Pacific native, frequently known as Protothaca staminea

Venerupis decussata
Grooved Carpet Shell, European native, also known as Ruditapes decussatus and Tapes decussatus

Ecology

General:

Ruditapes philippinarum is a burrowing bivalve, most abundant in shallow, subtropical to cool-temperate areas, in coarse sand and gravel. The sexes are separate. The clams can mature at sizes as small as 15 mm, especially in warmer climates (southern Japan, Hawaii) where they can spawn in their first year, but in cooler locations (northern Japan, Pacific Russia, Puget Sound) they begin spawning at 2 to 3 years of age at 22-35 mm (Yap 1977; Ponurovsky and Yakolev 1992). Spawning occurred year-round in Hawaii (Yap 1977), but was limited to 1 or 2 summer months in northern locations (Ponurovsky and Yakolev 1992). The minimum spawning temperature is around 12°C, but the optimal range is 20-22°C, although larval development can take place at 27-30°C (Toba et al. 1992, cited by Inoue et al. 2012). Fecundity of this bivalve increases with size, with 40 mm-long females producing about 1.5 - 2.4 million eggs (Yap 1977; Ponurovsky and Yakolev 1992). The eggs hatch into trochophore larvae, and within 2 days of hatching, develop a D-shaped shell. By 12-24 days, the larvae settle and attach to a shell or other hard surface with byssus threads, and soon move into the sediment (Toba et al. 1992, cited by Inoue et al. 2012).

Ruditapes philippinarum is most abundant in lower intertidal and shallow subtidal waters, often in estuaries and lagoons. Adult animals tolerate a wide range of salinities and temperatures from 12-50 PSU and 0-37°C, surviving under ice cover at the northern edge of their range (Breber 2002; Elston et al. 2003; Komorita et al. 2009; Kamenev and Nekrasov 2012). The range of salinity and temperature for reproduction is narrower, 24-35 PSU and 18-30°C (Toba et al. 1992, cited by Inoue et al. 2012; Food and Agricultural Organization 2013). In estuaries on the Pacific coast of Russia, the maximum longevity, estimated from shell rings, varied from 2 to 13 years (Ponurovsky and Yakolev 1992).

The Japanese Littleneck is a filter-feeder, taking in suspended particles through its incurrent siphon and trapping them on its gills. While larvae and juveniles feed mostly on phytoplankton, the adults in some locations may feed more heavily on benthic microalgae, primarily pennate diatoms, in the bottom surface film (Breber 2002). In the Fraser River Delta, isotopic measurements of V. philippinarum showed that they appear to be getting most of their nutrition from particulate organic matter (Sakamaki and Richardson 2008; Dias et al. 2019). At a site in Japan, terrestrial organic matter apparently makes only a minor contribution to their nutrition (Kasai et al. 2004). These somewhat contradictory results are suggestive of opportunistic feeding, varying with environmental conditions.

As a relatively large, but shallowly burrowing bivalve, R. philippinarum is a major prey item for native predators, such as moon snails, starfish, crabs, fishes, diving ducks, shorebirds, sea otters, and raccoons (Cohen 2005; Dudas et al. 2006; Cloern et al. 2007; Lewis et al. 2007; Gillespie et al. 2012). The introduced Green Crab (Carcinus maenas) is also a significant predator (Grosholz et al. 2001). This bivalve also supports numerous parasites, including a variety of bacteria, protozoans, trematodes, and the introduced parasitic copepod Mytilicola orientalis (Boweret al. 1992; Marshall et al. 2003; Gillespie et al. 2012). In Asian and European populations, protozoans of the genus Perkinsus cause significant mortality of R. philippinarum. These parasites have not yet been found on the Pacific coast of North America (Cigarria et al. 1997; Elston et al. 2003; Dungan and Reece 2006).

Food:

Phytoplankton

Trophic Status:

Suspension Feeder

SusFed

Habitats

General HabitatUnstructured BottomNone
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Tidal RangeLow IntertidalNone
Vertical HabitatEndobenthicNone


Tolerances and Life History Parameters

Minimum Temperature (ºC)0Survives under ice cover in the Amur estuary (Kamenev, and Nekrasov 2012)
Maximum Temperature (ºC)37 Experimental, acclimated at 25 C (Shin et al. 2000)
Minimum Salinity (‰)12.5Experimental (Elston et al. 2003). But survival decreases below 19.2 PSU at 18 and 24.5 C (Shin et al. 2000; Carregosa et al. 2014)
Maximum Salinity (‰)50In Italian lagoons (Breber 2002; Carregosa et al. 2014)
Minimum Reproductive Temperature18Lowest temperature for larval development (Toba et al. 1992, cited by Inoue et al. 2012)
Maximum Reproductive Temperature30Highest temperature for spawning (Toba et al. 1992, cited by Inoue et al. 2012)
Minimum Reproductive Salinity24Experimental, Food and Agricultural Organization 2013
Maximum Reproductive Salinity35Experimental, Food and Agricultural Organization 2013
Minimum Duration12At 27-30 C, (Toba et al. 1992, cited by Inoue et al. 2012)
Maximum Duration24At 18 C, (Toba et al. 1992, cited by Inoue et al. 2012)
Minimum Length (mm)15Minimum size at spawning (Ponurovsky and Yakolev 1992)
Maximum Length (mm)79Gillespie et al. 2012, but a more usual maximum is ~50 mm (Abbott 1974).
Broad Temperature RangeNoneCold temperature-Tropical
Broad Salinity RangeNoneMesohaline-Euhaline

General Impacts

Venerupis philippinarum is one of the most widely cultivated clam species in the world, both in its native Asian range, and in its introduced range in North America and Europe. It is a popular seafood species, and can be reared in dense populations in shallow waters (Breber 2002; Gillespie et al. 2102; Food and Agricultural Organization 2013). As a major new filter-feeder in its invaded regions, it has had important impacts on benthic communities, some resulting from the clams themselves, but larger impacts may have resulted from human disturbance due to harvesting and aquaculture (Breber 2002; Streftaris and Zenetos 2006; Ruesink et al. 2006; Pranovi et al. 2008; Bendell et al. 2010; Queiros et al. 2011; Sladonja et al. 2011).

Economic Impacts

Fisheries - Venerupis philippinarum is now one of the most widely harvested and consumed clams in the world. In 2010, worldwide production was 3.6 million metric tons. The 2nd highest production in the world in 2002 was in Italy with 41,000 metric tons, while the United States and France produced more than 1,000 tonnes each (Food and Agricultural Organization 2013). In 2004, Canada (British Columbia) harvested 1,500 tonnes (Whiteley and Bendell-Young 2007). Japanese Littlenecks are easily harvested, because they are shallow burrowers (California Department of Fish and Game 2001). In the US, they are frequently steamed, and eaten on the hard-shell. They are highly regarded for their flavor, according to cooking websites.

'Manila Clams' or 'Japanese Littlenecks' are often farmed by planting hatchery-raised seed, about 10-15 mm in size. They are planted in intertidal beach areas, or in shallow oyster ponds, at high density (Breber 2002; Carswell et al. 2006; Whiteley and Bendell-Young 2007; Sladonja et al. 2011; Food and Agriculture Organization 2013). The planted areas in British Columbia are often covered with plastic netting to prevent predation (Carswell et al. 2006; Munroe and McKinley 2007). In addition to aquaculture and commercial harvesting of 'wild' clams, recreational harvesting of these clams is popular in Europe and on the West Coast of the US (California Department of Fish and Game 2001; Fisheries and Oceans Canada 2009; Sladonja et al. 2011; Washington Department of Fish and Wildlife 2013). Both commercial and recreational fisheries are subject to closures because of industrial and agricultural pollution, and because of the occurrence of toxic algal blooms (California Department of Fish and Game 2001; Fisheries and Oceans Canada 2009; Sladonja et al. 2011; Washington Department of Fish and Wildlife 2013).

Ecological Impacts

Competition - The extent to which V. philippinarum displaces native bivalves by competition for food or space is unclear. On British Columbia intertidal shores, the density of other bivalves was not affected in beds of farmed Manila Clams, compared with reference sites (Whiteley and Bendell-Young 2007). However, a later survey in British Columbia indicates that V. philippinarum is replacing the native Pacific Littleneck (Leukona staminea) in farmed and non-farmed areas, despite the introduced clam's greater vulnerability to predation (Bendell 2014). In lagoons of the northern Adriatic, where V. philippinarum is intensively farmed, the native V. decussata (Grooved Carpet Shell) has become rare, but is still present. However, the sites where V. philippinarum is now most abundant, had relatively low densities of native species (Breber 2002).

Hybridization - A few hybrids between V. philippinarum and the native V. decussata (9 of 222 putative V. decussata - 4%) have been found in the Ria de Vigo, Spain. However, the extent and significance of genetic exchange between the two species is not known (Hurtado et al. 2011).

Habitat Change - As a relatively large and active, but shallow burrower, V. philippinarum is an important contributor to bioturbation in estuaries, but the importance of this effect in different areas (Poole Harbour, Bay of Arcachon, and Venice Lagoon) depended on sediment qualities, the presence of vegetation, and the other bioturbators in the community (Queiros et al. 2011). However, the largest effect of this species on habitats is due to the human development of aquaculture, which includes intensive planting of seed clams, increased deposition of organic matter, use of nets to exclude predators, and disturbance of sediments during commercial and recreational harvesting (Breber 2002; Carswell et al. 2006; Munroe and McKinley 2007; Bendell et al. 2010; Sladonja et al. 2011; Gillespie et al. 2012).

Food/Prey - As a large bivalve which frequently develops very high densities and biomasses, V. philippinarum is a potentially important prey item for a wide variety of predators in shallow subtidal and intertidal waters (Cohen et al. 2005; Gillespie et al. 2012). Its comparatively short siphon means that it is a relatively shallow burrower, and so more vulnerable. Buried clams with their extended siphons are often subject to sublethal predation, where the siphon is cropped by crabs and fishes. The siphon regrows, but V. philippinarum is forced to feed closer to the surface, making it more vulnerable to lethal predators, while the Pacific Littleneck (Leukoma staminea) with a longer siphon can remain at a safer depth (Meyer and Byers 2005). Major underwater predators include moon snails, crabs (Cancer productus, Metacarcinus magister, Carcinus maenas), starfish and a variety of fishes (Palacios and Ferraro 2003; Cohen 2005; Dudas et al. 2006; Cloern et al. 2007; Gillespie et al. 2012). Air-breathing predators include sea ducks, such as Scoters (Melanitta sp.); shorebirds, such as Oystercatchers (Haematopus spp.); otters; and raccoons (Cohen 2005; Caldow et al. 2007; Gillespie et al. 2012). In the case of the Eurasian Oystercatcher, the presence of populations of V. philippinarum appears to decrease winter mortality (Caldow et al. 2007).

Parasite/Predator Vector - In Atlantic and Mediterranean Spain, V. philippinarum and the native V. decussata suffered mortality due to protozoan parasites of the genus Perkinsus (Sagrista et al. 1996; Cigarria et al. 1997). The parasites appear to be native to the Northwest Pacific, and introduced to European waters with V. philippinarum. At least two species P. olseni and P. honshuesis are known from Asian V. philippinarum. The presence of these parasites has resulted in restrictions of importations to or transfers within European waters (Elston et al. 2003; Dungan and Reece 2006).

Trophic Cascade - Pranovi et al. (2008) argued that filter-feeding by V. philippinarum and other opportunistic species, and the disturbance due to clam harvesting, have altered the Lagoon of Venice's food web (Pranovi et al. 2008), reducing phytoplankton biomass and shifting the food web to one dominated by benthic filter-feeders (Pranovi et al. 2008). The extent to which this occurs in other systems is difficult to assess. The impacts of V. philippinarum may be limited by it short siphon, and tendency to filter benthic microalgae in the bottom surface films (Breber 2002).

Regional Impacts

MED-VIINoneEcological ImpactCompetition
Ruditapes philippinarum is now the dominant filter-feeder in the lagoons of the northern Adriatic (Pranovi et al. 2008). The native Venerupis decussata has become rare, but has not been eliminated. The native clam is now sold separately, at a higher price, due to 'snob appeal' (Breber 2002).
MED-VIINoneEcological ImpactHerbivory
Ruidtapes philippinarum is now the dominant filter-feeder in the Lagoon of Venice (Breber 2002; Pranovi et al. 2008).
MED-VIINoneEcological ImpactTrophic Cascade
Filter-feeding by Ruditapes philippinarum and other opportunistic species now dominates the Lagoon of Venice's food web (Pranovi et al. 2008), reducing phytoplankton biomass, and shifting the food web to one dominated by benthic filter-feeders (Pranovi et al. 2008).
MED-VIINoneEconomic ImpactFisheries
Aquaculture and harvesting of 'wild' Ruditapes philippinarum is now the primary fishery of the lagoons of the northern Adriatic, and the source of 95% of Italian clam production and 90% of the European R. philippinarum harvest (Sladonja et al. 2011). Mechanical harvesting of clams is now the dominant fishery in the Lagoon of Venice (Pranovi et al. 2008). Vibrating rakes have resulted in disturbance and resuspension of sediments, and have adversely affected habitats and other fisheries in the lagoon of Venice. A return to manual harvesting is desirable, but not economically feasible, unless encouraged by government incentives (Nunes and Markandya 2008).
NEA-IINoneEcological ImpactHabitat Change
In Poole Harbour, England, R. philippinarum, was the second most important species contributing to bioturbation of sediments (Queiros et al. 2011).
NEA-VNoneEcological ImpactHabitat Change
In the Basin of Arcachon, France, R. philippinarum, was the third most important species contributing to bioturbation of sediments (Queiros et al. 2011).
MED-VIINoneEcological ImpactHabitat Change
In the Lagoon of Venice, Italy, R. philippinarum, was the second most important species contributing to bioturbation of sediments (Queiros et al. 2011). However, a much larger factor in bioturbation is probably the effects of mechanical harvesting of the clams with vibrating rakes, which has led to extensive resuspension of sediments and siltation, with negative effects on habitat quality (Pranovi et al. 2008, Nunes and Markandya 2008).
NEP-IIIAlaskan panhandle to N. of Puget SoundEconomic ImpactFisheries
Ruditapes philippinarum is intensively farmed on the southern coast of British Columbia. These farms are planted with a high density of clam seed in leased sections of beaches, and often covered by netting to restrict predators (Carswell et al. 2006; Munroe et al. 2007; Whiteley and Bendell-Young 2007; Bendell et al. 2010). In Baynes Sound, these farms occupied about 20% of the shoreline, with 3% covered by netting (Carswell et al. 2006). Japanese littlenecks are also frequently harvested by recreational shellfishers in British Columbia and Washington (Fisheries and Oceans Canada 2009; Washington Department of Fish and Wildlife 2013)
NEP-IIIAlaskan panhandle to N. of Puget SoundEcological ImpactHabitat Change
Sites in which farming of R. philippinarum took place had 'significantly greater amounts of ammonium, phosphorus and manganese in bulk and organic matter, and ammonium, iron, manganese and silt in surficial sediments' (Bendell et al. 2010). Antipredator nets at these sites may increase the deposition of silt and sediments (Bendell et al. 2010). However, farming activity did not affect the abundance of other bivalve species at the sites (Whiteley and Bendell-Young 2007).
NEA-VNoneEcological ImpactHybridization
Of 328 'Venerupis' spp. sampled in the Ria de Vigo, Spain, nine were apparent hybrids, based on DNA sequences and chromosome studies. The spawning seasons of these two bivalves partially overlap and the chromosomes of hybrids appear to pair normally (Hurtado et al. 2011). However, the frequency and significance of genetic exchange between the species is not known.
NEP-IIIAlaskan panhandle to N. of Puget SoundEcological ImpactFood/Prey
Ruditapes philippinarum may be more vulnerable to predators than the native Leukoma staminea (Pacific Littleneck) because of its shorter siphon. Simulated sublethal predation (cropping the siphon) caused R. philippinarum to bury at shallower Repths, making it more vulnerable to predators, while L. staminea, even after losing 40% of its siphon, remained at the same depth (Meyer and Byers 2005). Sea ducks (Surf Scoter- Melanitta perspicillata; White-Winged Scoter- M. fusca) fed primarily on R. philippinarum and Nuttallia obscurata (Purple Varnish Clam) in Britsh Columbia waters. Scoter predation appeared to be the primary cause for winter decline in these bivalves (Lewis et al. 2007).
SP-XXINoneEconomic ImpactFisheries
Ruditapes philippinarum was stocked, several times in Oahu, possibly in the 1880-90s, and then before 1918, and in 1920, and then transplanted to other islands. Harvesting at several locations has been intense enough to reduce, or eliminate local populations (Yap 1977; Carlton and Eldredge 2009).
NEP-IVPuget Sound to Northern CaliforniaEcological ImpactFood/Prey
Palacios and Ferraro (2003) found that Carcinus maenas (Green Crabs) fed at high rates on R. philippinarum and other bivalves at high rates, though O. lurida (Olympic Oysters) were the preferred prey.
P290Puget SoundEconomic ImpactFisheries
Ruditapes philippinarum (Manila Clam, Japanese Littleneck) is reared in shellfish farms and fished recreationally in Puget Sound (Washington Department of Fish and Wildlife 2013).
P280Grays HarborEconomic ImpactFisheries
Japanese littlenecks are frequently harvested by recreational shellfishers in Washington. Copalis Beach, in Grays Harbor, is a popular site (Washington Department of Fish and Wildlife 2013).
P270Willapa BayEconomic ImpactFisheries
Ruditapes philippinarum (Manila Clam, Japanese Littleneck) is reared in shellfish farms and fished recreationally in Willapa Bay (Ruesink et al. 2006; Washington Department of Fish and Wildlife 2013).
NEP-IVPuget Sound to Northern CaliforniaEconomic ImpactFisheries
Ruidtapes philippinarum (Manila Clam, Japanese Littleneck) is reared in shellfish farms in Willapa Bay and Humboldt Bay, and fished recreationally in Grays Harbor, Willapa Bay and Humboldt Bays (Ruesink et al. 2006; California Department of Health Services 2007; Washington Department of Fish and Wildlife 2013, http://wdfw.wa.gov/fishing/shellfish/clams/).
P130Humboldt BayEconomic ImpactFisheries
Ruditapes philippinarum (Manila Clam, Japanese Littleneck) is reared in shellfish farms in Humboldt Bay in small quantities (California Department of Health Services 2007).  Recreational shellfishing for these clams is also popular (California Department of Fish and Game 2001).
NEP-VNorthern California to Mid Channel IslandsEconomic ImpactFisheries
San Francisco Bay supports dense populations of Ruditapes philippinarum, which have attracted recreational clammers. However, water quality issues have limited harvests (California Department of Fish and Game 2001). In Tomales Bay, they are cultured as 'Manila Clams' in several shellfish farms, according to local websites.
NEP-VNorthern California to Mid Channel IslandsEcological ImpactFood/Prey
Ruditapes philippinarum is a common food item for moon snails, sturgeon, gulls, shorebirds, ducks, and raccoons (Cohen and Carlton 1995).
P110Tomales BayEconomic ImpactFisheries
In Tomales Bay, Ruditapes philippinarum are cultured as 'Manila Clams' in several shellfish farms, according to local websites.
P090San Francisco BayEconomic ImpactFisheries
San Francisco Bay supports dense populations of Ruditapes philippinarum, which have attracted recreational clammers. However, water quality issues have limited harvests (California Department of Fish and Game 2001).
P050San Pedro BayEcological ImpactCompetition
In Colorado Lagoon, Long Beach CA, Ruditapes philippinarum became the biomass dominant in the benthic community by 2004, as the previous dominant, the introduced Hard Clam, Mercenaria mercenaria, disappeared. Competition is possible, but when R. philippinarum appeared, M. mercenaria had already become rare (Burnaford et al. 2011).
NEP-VIPt. Conception to Southern Baja CaliforniaEcological ImpactCompetition
In Colorado Lagoon, Long Beach, CA Ruditapes philippinarum became the biomass dominant in the benthic community by 2004, as the previous dominant, the introduced Hard Clam, Mercenaria mercenaria, disappeared. Competition is possible, but when R. philippinarum appeared, M. mercenaria had already become rare (Burnaford et al. 2011).
NEA-IIINoneEconomic ImpactFisheries
Although Ruditapes philippinarum does not breed in Irish waters, Ireland supports successful hatchery-based culture operations in Drumcliff Bay, Cork Harbour, and other locations (Drummond et al. 2006).
NEA-IINoneEconomic ImpactFisheries
In French waters, hatchery stocks were established in 1972, and a commercial fishery was established by 1984. By 1992, it was sustained by natural breeding, although adversely affected by Vibrio infections. The harvested clams were mostly exported to Spain (Flaasch and LeBorgne 1992). A winter fishery has developed in Poole Harbour, England, for R. philippinarum. The fishery depresses clam abundance, but appears to be sustainable (Humphreys et al. 2007).
NEA-IVNoneEconomic ImpactFisheries
In French waters, hatchery stocks were established in 1972, and a commercial fishery was established by 1984. By 1992, it was sustained by natural breeding, although adversely affected by Vibrio infections. The harvested clams were mostly exported to Spain (Flaasch and LeBorgne 1992).
NEA-VNoneEconomic ImpactFisheries
In French waters, hatchery stocks of R. philippinarum were established in 1972, and a commercial fishery was established by 1984. By 1992, it was sustained by natural breeding, although adversely affected by Vibrio infections. The harvested clams were mostly exported to Spain (Flaasch and LeBorgne 1992). In Spain, culture of this clam began in 1980 (Cigarria et al. 1997). A fishery for R. philippinarum in the Ria Arousa, Spain, has been proposed to be certified as environmentally sustainable by the Marine Stewardship Council, Spain, a designation which is disputed by Galil et al. (2013).
NEA-IINoneEcological ImpactFood/Prey
In Poole Harbour, England, R. philippinarum may be an important food for Eurasian Oystercatchers (Haematopus ostralegus), a bird considered to be an indicator of ecosystem health (Jensen et al. 2004). Modeling suggests that the high density of R. philippinarum has reduced winter mortality of the Eurasian Oystercatcher at Poole Harbour. The spread of this clam is considered a potential benefit to European shorebirds (Caldow et al. 2007). Excretion of inorganic carbon and nutrients by R. philippinarum stimulates microbial activity in intertidal sandflats, both when submerged at high tides, and energed at low tides (Mign et al. 2018). However, it is unclear whether these effects are different feom those of natïve bivalves.
NEA-VNoneEcological ImpactParasite/Predator Vector
In the Eo estuary, Spain, R. philippinarum has suffered mortality due to protozoan parasites of the genus Perkinsus (Cigarria et al. 1997). The parasites appear to be native to the Northwest Pacific, and introduced to European waters. At least two species, P. olseni and P. honshuesis, are known from Asian R. philippinarum (Elston et al. 2003; Dungan and Reece 2006).
MED-IINoneEcological ImpactParasite/Predator Vector
Perkinsus olseni (as P. atlanticus) was reported to cause serious mortality of R. philippinarum and Venerupis decussata on clam farms in the Ebro Delta, Spain.
NEP-IIIAlaskan panhandle to N. of Puget SoundEcological ImpactCompetition
Ruditapes philippinarum appears to be replacing the native Leukoma staminea (Pacific Littleneck) in farmed areas and reference sites, despite its greater vulnerablity to predators, partly because of the intensity of seeding in farmed areas (Bendell 2014).
NEA-VNoneEcological ImpactCompetition
Ruditapes philippinarum is considered a potential competitor of the native Venerupis decussatus, but the two species differ somewhat in their ecological preferences, with R. philippinarum being more abundant in regions of less sand, slower current, ande higher organic content (Bidegain et al. 2015). In the Tagus estuary, Portugal, the growth performance of R. philippinarum was much higher than that of V. decussatus, whise population is delining (Moura et al. 2017).
NEA-VNoneEcological ImpactHerbivory
Brito et al. (2015) have attributed a decrease in phytoplankton abundance and average size, in the Tagus estuary, Portugal, to development of a large biomass of R. philippinarum. They estimate that R. philippinarum could clear the water column in 10 days (Brito et al. 2015).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
SP-XXI None 1918 Def Estab
NWP-4a None 0 Native Estab
NWP-3a None 0 Native Estab
NWP-2 None 0 Native Estab
EAS-IV None 0 Native Estab
EAS-III None 0 Native Estab
NEP-III Alaskan panhandle to N. of Puget Sound 1924 Def Estab
NEP-IV Puget Sound to Northern California 1947 Def Estab
NEP-V Northern California to Mid Channel Islands 1946 Def Estab
MED-II None 1980 Def Estab
MED-III None 1985 Def Estab
MED-VII None 1983 Def Estab
NEA-V None 1980 Def Estab
AR-V None 1988 Def Unk
NEA-IV None 1974 Def Estab
SP-VII None 1965 Def Unk
NEA-II None 1974 Def Estab
EAS-I None 0 Native Estab
EAS-II None 0 Native Estab
CIO-V None 0 Native Estab
CIO-II None 0 Native Estab
SP-XVI None 1980 Def Unk
NWP-3b None 0 Native Estab
NWP-4b None 0 Native Estab
MED-VI None 2001 Def Estab
MED-VIII None 2005 Def Estab
P130 Humboldt Bay 1964 Def Estab
P050 San Pedro Bay 1998 Def Estab
P170 Coos Bay 1986 Def Failed
NEP-VI Pt. Conception to Southern Baja California 1998 Def Estab
P040 Newport Bay 1998 Def Estab
P062 _CDA_P062 (Calleguas) 2000 Def Estab
P070 Morro Bay 1953 Def Failed
P080 Monterey Bay 1949 Def Estab
P090 San Francisco Bay 1946 Def Estab
P095 _CDA_P095 (Tomales-Drakes Bay) 1966 Def Estab
P110 Tomales Bay 1954 Def Estab
P112 _CDA_P112 (Bodega Bay) 1949 Def Estab
P230 Netarts Bay 1965 Def Estab
P240 Tillamook Bay 1965 Def Failed
P210 Yaquina Bay 1965 Def Failed
P270 Willapa Bay 1946 Def Estab
P280 Grays Harbor 1964 Def Estab
P286 _CDA_P286 (Crescent-Hoko) 2002 Def Estab
P284 _CDA_P284 (Hoh-Quillayute) 2002 Def Estab
P290 Puget Sound 1943 Def Estab
P293 _CDA_P293 (Strait of Georgia) 1924 Def Estab
P297 _CDA_P297 (Strait of Georgia) 1963 Def Estab
P292 _CDA_P292 (San Juan Islands) 1950 Def Estab
NWP-5 None 0 Native Estab
EAS-VI None 0 Native Estab
NEA-III None 1984 Def Estab
P093 _CDA_P093 (San Pablo Bay) 1949 Def Estab
MED-IV None 2006 Def Estab
P030 Mission Bay 2012 Def Estab
P065 _CDA_P065 (Santa Barbara Channel) 2011 Def Unk
P023 _CDA_P023 (San Louis Rey-Escondido) 2011 Def Unk
P061 _CDA_P061 (Los Angeles) 2016 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude
26583 Quayle 1964, cited by Carlton 1979 1964 1964-01-01 Humboldt Bay General Location Def 40.7864 -124.1922
26829 Foss 2009 2005 2005-11-14 California Maritime Academy, Vallejo Def 38.0661 -122.2299
27530 Cohen, et al. 2005 (SF Bay Area RAS) 2004 2004-05-24 Fruitvale Bridge, San Francisco Bay Def 37.7690 -122.2296
27610 Foss 2009 2005 2005-09-09 San Mateo Bridge Def 37.5806 -122.2543
27704 Nichols and Thompson 1985a 1985 1985-01-01 Chipps Island, Suisun Bay Def 38.0713 -122.0581
28023 Foss 2009 2005 2005-10-21 Romberg Tiburon Center Def 37.8906 -122.4458
28232 California Department of Fish and Wildlife 2014 2011 2011-04-07 Private Dock, Channel Islands Harbor Def 34.1798 -119.2297
28892 Foss 2009 2005 2005-07-06 Coyote Point Def 37.5920 -122.3210
28976 Fairey et al. 2002 2000 2000-09-13 Port Hueneme Infaunal 02 Def 34.1531 -119.2101
29328 Foss 2009 2005 2005-06-09 Paradise Area Def 37.9062 -122.4768
29477 Foss 2011 2010 2010-06-12 McNears Beach Def 37.9962 -122.4556
29510 Foss 2011 2010 2010-07-12 Cruise Ship Pier Def 37.8085 -122.4060
29586 California Department of Fish and Wildlife 2014 2011 2011-05-05 Middle Harbor Yacht Slip Def 33.2106 -117.3960
29760 Carlton 1979 1949 1949-01-01 Bodega Bay Def 38.3262 -123.0495
29915 Wasson et al, 2001 (Elkhorn Slough Survey) 1998 1998-03-01 Highway I Bridge, Moss Landin, Elkhorn Slough Def 36.8090 -121.7841
29975 Foss 2009 2005 2005-06-08 Sea Plane Lagoon Def 37.7761 -122.2998
30076 Los Angeles/Long Beach Baseline Study (2000) 2000 2000-01-01 Los Angeles/Long Beach Harbor Complex Def 33.7632 -118.2526
30334 Nichols and Thompson 1985a 1985 1985-01-01 South San Francisco Bay Def 37.5457 -122.1645
30398 Carlton 1979 1949 1949-01-01 Elkhorn Slough General Location Def 36.8086 -121.7856
30599 Carlton 1979 1946 1946-01-01 San Francisco Bay Def 37.8494 -122.3681
30876 Foss 2009 2005 2005-10-19 Hercules Wharf, San Pablo Bay Def 38.0231 -122.2928
31229 Carlton 1979 1966 1966-01-01 Bolinas Lagoon Def 37.9189 -122.6816
31711 Foss 2009 2005 2005-08-19 Ayala Cove Def 37.8680 -122.4350
31816 California Department of Fish and Wildlife 2011 2011 2011-04-06 Radon Corner Def 34.4047 -119.6937
31966 Foss 2009 2005 2005-07-08 Richmond Marina Def 37.9137 -122.3504
32571 Foss 2009 2005 2005-06-09 Point Cavallo Def 37.8319 -122.4737
32632 Foss 2011 2005 2005-11-15 China Camp Def 38.0025 -122.4617
32889 California Department of Fish and Wildlife 2011 2011 2011-04-19 Balboa Coves Def 33.6213 -117.9364
32985 Fairey et al. 2002 2000 2000-09-13 Port Hueneme Infaunal 10 Def 34.1506 -119.2068
33110 Foss 2009 2005 2005-06-08 Crown Beach Def 37.7603 -122.2737
33239 Foss 2011 2010 2010-06-30 Rodeo Marina Def 38.0394 -122.2717
33596 Cohen, et al. 2005 2004 2004-05-23 Brisbane Lagoon, San Francisco Bay Def 37.6862 -122.3906
33712 Burch 1955, cited by Carlton 1979 1955 1955-01-01 Tomales Bay Def 38.2100 -122.9400
768119 Ruiz et al., 2015 2012 2012-09-04 Redwood City Marina, San Francisco Bay, CA, California, USA Def 37.5023 -122.2130

References

Aarnio, Katri; Törnroos, Anna; Björklund, Charlotta; Bonsdorff, Erik (2015) Food web positioning of a recent coloniser: the North American Harris mud crab Rhithropanopeus harrisii (Gould, 1841) in the northern Baltic Sea, Aquaitc Invasions 10: In press

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

2002-2016a Malacology Collection Search. http://clade.ansp.org/malacology/collections/

2006-2014b OBIS Indo-Pacific Molluscan Database. http://data.acnatsci.org/obis/

Albayrak, Serhat (2011) Alien marine bivalve species reported from Turkish seas, Cahiers de Biologie Marine 52: 107-118

Amor, Kounofi-Ben; Rifi, M.; Ghanem, R.; Draief, I.; Zouali, J.; Souissi, J. Ben (2016) Update of alien fauna and new records of Tunisian marine fauna, Mediterranean Marine Science 17(1): 124-143

Anacleto, Patrícia and 7 authors (2014) Ecophysiology of native and alien-invasive clams in an ocean warming context, Comparative Biochemistry and Physiology, Part A 175: 28-37

Antit, M.; Gofas, S.; Salas, C.; Azzouna, A. (2011) One hundred years after Pinctada: an update on alien Mollusca in Tunisia, Mediterranean Marine Science 12(1): 53-73

Baldwin, Andy; Leason, Diane (2016) Potential Ecological impacts of Emerald Ash Borer on Maryland's Eastern Shore, In: None(Eds.) None. , <missing place>. Pp. <missing location>

Bendell, L. I. (2014) Evidence for declines in the native Leukoma staminea as a result of the intentional introduction of the non-native Venerupis philippinarum in coastal British Columbia, Canada, Estuaries and Coasts 37: 369-380

Bendell, L. I.; Duckham, C.; L’Espérance, T.; Whiteley, J. A. (2010) Changes in geochemical foreshore attributes as a consequence of intertidal shellfish aquaculture: a case study, Marine Ecology Progress Series 404: 91-108

Bidegain, Gorka; Juanes, José Antonio (2013) Does expansion of the introduced Manila clam Ruditapes philippinarum cause competitive displacement of the European native clam Ruditapes decussatus?, Journal of Experimental Marine Biology and Ecology 445: 44-52

Bidegain, Gorka; Barcena, Javier Francisco; García, Andres; Juanes, Jose Antonio (2015) Predicting coexistence and predominance patterns between the introduced Manila clam (Ruditapes philippinarum) and the European native clam (Ruditapes decussatus), Estuarine, Coastal and Shelf Science 152: 162-172

Bower, S.M., Blackbourn, J., Meyer, G.R. (1992) Parasite and symbiont fauna of Japanese littlenecks, Tapes philippinarum (Adams and Reeve, 1850), in British Columbia, Journal of Shellfish Research 11(1): 13-19

Boyd, Milton J.; Mulligan, Tim J; Shaughnessy, Frank J. (2002) <missing title>, California Department of Fish and Game, Sacramento. Pp. 1-118

Breber, Paolo (2002) Invasive Aquatic Species of Europe> distribution, impacts, and management, Kluwer, Dordrecht. Pp. 120-126

Brito, Ana C.; Moita, Teresa; Gameiro, Carla; Silva, Teresa; Anselmo, Tânia Brotas, Vanda (2015) Changes in the phytoplankton composition in a temperate estuarine system (1960 to 2010), Estuaries and Coasts 38: 1678-1691

Brock, Vernon E. (1960) The introduction of aquatic animals into Hawaiian waters, Internationale Revue der Gesamten Hydrobiologie 45(4): 463-480

Burfeind, Dana D.; Pitt, Kylie A.; Connolly, Rod M.; Byers, James E. (2012) Performance of non-native species within marine reserves, Biological Invasions published online: <missing location>

Burnaford, Jennifer L.; Henderson, Scottie Y. Pernet, Bruno (2011) Assemblage shift following population collapse of a non-indigenous bivalve in an urban lagoon, Marine Biology 158: 1915-1927

Byers, James E. (2005) Marine reserves enhance abundance but not competitive impacts of a harvested nonindigenous species., Ecology 86(2): 487-500

California Department of Fish and Game (2001) California’s Living Marine Resources: A Status Report, California Department of Fish and Game, Sacramento CA. Pp. 450-451

California Department of Fish and Wildlife (2014) Introduced Aquatic Species in California Bays and Harbors, 2011 Survey, California Department of Fish and Wildlife, Sacramento CA. Pp. 1-36

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

Carl, G. Clifford; Guiguet, C. J. (1972) Alien animals in British Columbia., British Columbia Provincial Museum: Department of Recreation and Conservation: Handbook 14: 1-102

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. (1989) <missing title>, <missing publisher>, <missing place>. Pp. <missing location>

Carlton, James T. (Ed.) (2007) <missing title>, University of California Press, Berkeley. Pp. <missing location>

Carlton, James T.; Eldredge, Lucius (2009) Marine bioinvasions of Hawaii: The introduced and cryptogenic marine and estuarine animals and plants of the Hawaiian archipelago., Bishop Museum Bulletin in Cultural and Environmental Studies 4: 1-202

Carregosa, Vanessa and 6 authors (2014) Tolerance of Venerupis philippinarum to salinity: Osmotic and metabolic aspects, Comparative Biochemistry and Physiology Part A: Physiology 171: 36-43

Carswell, Barron; Cheesman, Sean; Anderson, Josh (2006) The use of spatial analysis for environmental assessment of shellfish aquaculture in Baynes Sound, Vancouver Island, British Columbia, Canada, Aquaculture 253: 408-414

Chiesa, Stefania and 8 authors (2011) The invasive Manila clam Ruditapes philippinarum (Adams and Reeve, 1850) in Northern Adriatic Sea: Population genetics assessed by an integrated molecular approach, Fisheries Research 110: 259-267

Cigarria, J.; Rodriguez, C.; Fernandez, J. M. (1997) Impact of Perkinsus sp. on Manila clam Ruditapes philippinarum beds, Diseases of Aquatic Organisms 29: 117-120

Çinar, M. E.; Noglu, M. Bilece; Özturk, B.; Katagan, T. ; Aysel, V. (2005) Alien species on the coasts of Turkey, Mediterranean Marine Science 6/2: 119-146

Cladow, Richard W. G. and 7 authors (2007) Benefits to shorebirds from invasion of a non-native shellfish., Proceedings of the Royal Society of London B 274: 1449-1455

Cloern, James E.; Jassby, Alan D.;Thompson, Janet K.; Hieb, Kathryn A. (2007) A cold phase of the East Pacific triggers new phytoplankton blooms in San Francisco Bay, Proceedings of the National Academy of Sciences 104(47): 18561-18565

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) <missing title>, Santa Barbara Museum of Natural history, Santa Barbara CA. Pp. <missing location>

Cohen, Andrew N. (2004) <missing title>, San Francisco Estuary Institute, San Francisco CA. Pp. 1-50

2005 Exotics Guide. San Francisco Estuary Institute, Oakland, CA, www.exoticsguide.org

Cohen, Andrew N. and 10 authors (2005) <missing title>, San Francisco Estuary Institute, Oakland CA. Pp. <missing location>

Cohen, Andrew N. and 22 authors (2001) <missing title>, Washington State Department of Natural Resources, Olympia. Pp. <missing location>

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>

Cohen, Andrew N.; Chapman, John T. (2005) <missing title>, San Francisco Estuary Institute, San Francisco. Pp. <missing location>

Cohen, Andrew; and 16 authors. (1998) <missing title>, Washington State Department of Natural Resources, Olympia, Washington. Pp. 1-37

Coles S. L., DeFelice R. C., Eldredge, L. G. (1999a) Nonindigenous marine species introductions in the harbors of the south and west shores of Oahu, Hawaii., Bishop Museum Technical Report 15: 1-212

Coles, S. L.; DeFelice, R. C. : Eldredge, L. G. (2002a) Nonindigenous marine species in Kaneohe Bay, Oahu, Hawai`i, Bishop Museum Technical Report 24: 1-364

Coles, S. L.; DeFelice, R. C.; Eldredge, L. G.; Carlton, J. T. (1999b) Historical and recent introductions of non-indigenous marine species into Pearl Harbor, Oahu, Hawaiian Islands., Marine Biology 135(1): 147-158

Collado-Vides, L. (2002) Morphological plasticity of Caulerpa prolifera (Caulerpales, Chlorophyta) in relation to growth form in a coral reef lagoon, Botanica Marina 45: 123-129

Crocetta, Fabio (2011) Marine alien Mollusca in the Gulf of Trieste and neighbouring areas: a critical review and state of knowledge (updated in 2011), Acta Adriatica 52(2): 247 - 260,

Crocetta, Fabio (2012) Marine alien Mollusca in Italy: a critical review and state of the knowledge, Journal of the Marine Biological Association of the United Kingdom 92(6): 1357-1365

de Montaudouin, Xavier; Sauriau, Pierre-Guy (2000) Contributions to a synopsis of marine species richness in the Pertuis-Charentais Sea with new insights into the soft-bottom macrofauna of the Marennes-Oleron Bay, Cahiers de Biologie Marine 41: 181-222

de Rivera, Catherine, and 27 authors (2005a) <missing title>, National Fish and Wildlife Foundation, Washington, D.C.. Pp. <missing location>

Drummond, Linda; Mulcahy, Maire; Culloty, Sarah (2006) The reproductive biology of the Manila clam, Ruditapes philippinarum, from the North-West of Ireland, Aquaculture 254: 326-340

Dudas, Sarah E.; McGaw, Iain J. ; Dower, John F. (2006) Selective crab predation on native and introduced bivalves in British Columbia., Journal of Experimental Marine Biology and Ecology 325: 8-17

Dungan, Christopher F.; Reece, Kimberly S. (2006) In vitro propagation of two Perkinsus spp. parasites from Japanese Manila Clams Venerupis philippinarum and description of Perkinsus honshuensis n. sp., Journal of Eukaryotic Microbiology 53(5): 316-326

Eldredge, L. G. (1994) Introductions of Commercially Sginificant Aquatic Organsisms to th Pacific Islands, South Pacific Commission, Noumea, New Caledonia. Pp. <missing location>

Eldredge, L.G. (1994) Perspectives in aquatic exotic species management in the Pacific Islands Vol. I. Introductions of commercially significant aquatic organisms to the Pacific islands, South Pacific Commission. Inshore Fisheries Research Project, Technical Document 7: 1-127

Elston, Ralph A.; Cheney, Daniel P.; Macdonald, Brian F.; Suhrbier, Andrew D.. (2003) Tolerance and response of Manila clams, Venerupis philippinarum (A. Adams and Reeve, 1850) to low salinity., Journal of Shellfish Research 22(3): 667-674

Elston, Ralph A.; Dungan, Christopher F.; Meyers, Theodore R.; Reece, Kimberly S. (2003) Perkinsus sp. infection risk for manila clams, Venerupis philippinarium on the Pacific Coast of North and Central America., Journal of Shellfish Research 22(3): 661-665

Environment Canada (1994) Fraser River Benthic Invertebrate Catalogue, In: None(Eds.) None. , <missing place>. Pp. <missing location>

Fairey, Russell; Dunn, Roslyn; Sigala, Marco; Oliver, John (2002) <missing title>, California Department of Fish and Game, Sacramento. Pp. <missing location>

Fischer, W.; Schneider, M.; Bauchot, M.-L. (1987) <missing title>, FAO-CEE, Rome. Pp. <missing location>

2009 Manila Clam. http://www.pac.dfo-mpo.gc.ca/science/species-especes/shellfish-coquillages/clam-palourde/manila-japonaise-eng.htm

Flassch, J. P. ; Leborgne, Y. (1992) Introduction in Europe, from 1972 to 1980, of the Japanese Manila clam Tapes philippinarum) and the effects on aquaculture production and natural settlement, International Council for Exploration of the Marine Science Symposium 194: 92-96

1998-2012 Database on Introductions of Aquatic Species. Web address http://www.fao.org/fishery/introsp/search/en

2013 Cultured Aquatic Species Information Programme, <i>Ruditapes philippinarum</i> (Adams & Reeve, 1850). <missing description>

Foss, Stephen (2009) <missing title>, California Department of Fish and Game, Sacramento CA. Pp. <missing location>

Foss, Stephen (2011) <missing title>, California Department of Fish and Game, Office of Spill Prevention and Response, Sacramento. Pp. 54

Galil, Bella S.; Genovesi, Piero; Ojaveer, Henn; Quilez-Badia, Gemma; Occhipinti, Anna (2013) Mislabeled: eco-labeling an invasive alien shellfish fishery, Biological Invasions published online: <missing location>

Genez, Pinar; Önal, Umur; Gezen, Mehmet R. (2015) Comparison of gametogenic cycles of the endemic European Carpet Shell Clam (Ruditapes decussatus) and the introduced Manila Clam (Ruditapes philippinarum) from a temperate coastal Mediterranean lagoon in the Dardanelles, Turkey, Journal of Shellfish Research 34(2): 337-345

Gillespie, Graham E.; Bower, Susan M.; Marcus, Kerry L.; Kieser, Dorothee (2012) <missing title>, Canadian Science Advisory Secretariat, Fisheries and Oceans Canada, Ottawa, Ontario. Pp. 1-97

2007 Distribution of nonindigenous intertidal species on the Pacific Coast of Canada. http://www.pices.int/publications/presentations/PICES_15/Ann15_S8/S8_Gillespie.pdf

Golikov, A. N. and 7 other editors. (1976) <missing title>, Nauk, Leningrad. Pp. <missing location>

Goulletquer, Philippe; Bachelet, Guy; Sauriau, Pierre; Noel, Pierre (2002) Invasive aquatic species of Europe: Distribution, impacts, and management., Kluwer Academic Publishers, Dordrecht. Pp. 276-290

Grosholz, Edwin; Olin, Paul; Williams, Briar; Tinsman, Rico (2001) Reducing predation on manila clams by nonindigenous European green crabs., Journal of Shellfish Research 20(3): 913-919

Herbert, Roger J. H. and 7 authors (2012) Invasion in tidal zones on complex coastlines: modelling larvae of the non-native Manila clam, Ruditapes philippinarum, in the UK, Journal of Biogeography 39: 585-599

Hopkins, Dale R. (1986) Atlas of the distributions and abundances of common benthic species in San Francisco Bay, California, US Geological Survey Water Resources Investigations Report 86-4003: 1-16+ 25+228

Huang, Zongguo (Ed.) (2001) <missing title>, Krieger, Malabar, FL. Pp. <missing location>

Humphreys, John; Caldow, Richard W. G.; McGrorty, Selwyn ; West Andrew D.; Jensen, Antony C. (2007) Population dynamics of naturalised Manila clams Ruditapes philippinarum in British coastal waters., Marine Biology 151: 2255-2270

Humphreys, John; Harris, Matthew R. C.; Herbert, Roger J. H.; Farrell, Paul; Jensen, Antony; Cragg, Simon M. (2015) Introduction, dispersal and naturalization of the Manila clam Ruditapes philippinarum in British estuaries, 1980–2010, Journal of the Marine Biological Association of the United Kingdom 95(6): 1163-1172

Hurtado, Ninoska S.; Pérez-García, Concepción P; Morán, Paloma; Pasantes, Juan J. (2011) Genetic and cytological evidence of hybridization between native Ruditapes decussatus and introduced Ruditapes philippinarum (Mollusca, Bivalvia, Veneridae) in NW Spain, Aquaculture 311: 123-128

Inoue, Nariaki and 5 authors (2012) SEM observations on larval shell morphology of Manila clam Ruditapes philippinarum and their utility, Fisheries Science 78: 1237-1243

International Commission for the Scientific Exploration of the Mediterranean Sea (CEISM) (2001) <missing title>, <missing publisher>, <missing place>. Pp. <missing location>

Ivanova, M. B.; Belogurova, L. S.; Tsurpalo, A. P. (2008) Ecological studies and the state of the ecosystem of Amursky Bay and the estuarine zone of the Razdolnaya River (Sea of Japan) Vol. 1., Dalnauka, Vladivostok, Russia. Pp. 1-140

Jensen, A. C.; Humphreys, J.Caldow, R. W. G.; Grisley, C.; Dyrynda, P. E. J. (2004) Naturalization of the Manila clam Tapes philippinarum, an alien species, and establishment of a clam fishery within Poole Harbour, Dorset., Journal of the Marine Biological Association 84: 1069-1073

Jimenez, H.; Ruiz, G. M. (2016) Contribution of non-native species to soft-sediment marine community structure of San Francisco Bay, California, Biological Invasions Publshed online: <missing location>

Jung, Jongwoo (2012) New record of a naidid oligochaete species, Ripistes parasita (Annelida: Clitellata: Naididae) from Korea, Animal Systematic, Evolution, and Diversity 28(2): 137-139

Kamenev, Gennady M.; Nekrasov, Dmitry A. (2012) Bivalve fauna and distribution in the Amur River estuary: A warm-water ecosystem in the cold-water Pacific region, Marine Ecology Progress Series 455: 195-210

Kasai, Akihide; Horie, Hisako; Sakamoto, Wataru (2004) Selection of food sources by Ruditapes philippinarum and Mactra veneriformis (Bivalva: Mollusca) determined from stable isotope analysis, Fisheries Science 70: 11-20

Kennedy, C., Pappal, A. L.; Bastidas, C.; ; Carlton, J. T.; David, A. A.; Dijkstra, J.A.; Duffey, S; Gibson, J.; Grady, S. P.; Green-Gavrielidis, (2020) . Report on the 2018 Rapid Assessment Survey of Introduced, Cryptogenic, and Native Marine Species at New England Marinas: Massachusetts to Maine. , <missing publisher>, Bostom MA. Pp. <missing location>

Kil, Hyun Jong; Yoon, Sook Hee; Kim, Won; Choe, Byung Lae; Sohn, Hyun Joon; Park, Joong-Kee (2005) Faunistic investigation for marine mollusks in Jindo Island., Korean Journal of Systematic Zoology Special Issue 5: 29-46

Komorita, Tomohiro and 5 authors (2009) Impact of low temperature during the winter on the mortality in the post-settlement period of the juvenile of short-neck clam, Ruditapes philippinarum, on the tidal flats in Hichirippu Lagoon, Hokkaido, Japan, Plankton & Benthos Research 41(1): 31-37

LeJart, Morgane; Hily, Christian (2011) Differental response of macrobenthos to formation of novel oyster reefs (Crassostrea gigas Thunberg) on soft and rocky substrate in theinteridal of the Bay of Brest, France, Journal of Sea Research 65: 84-93

Lewis, Tyler L.; Esler, Daniel; Boyd, W. Sean (2007) Effects of predation by sea ducks on clam abundance in soft-bottom intertidal habitats, Marine Ecology Progress Series 329: 131-144

Lipej, L.; Mavric, B.; Orlando-Bonaca, M.; Malej, A. (2012) State of the art of the marine non-indigenous flora and fauna in Slovenia, Mediterranean Marine Science 13(2): 243-249

Liu, Wenliang; Liang, Xiaoli ; Zhu, Xiaojing (2015) A new record and mitochondrial identification of Synidotea laticauda Benedict, 1897 (Crustacea: Isopoda: Valvifera: Idoteidae) from the Yangtze Estuary, China, Zootaxa 4294: 371-380

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

Mach, Megan E.; Levings, Colin D.; Chan, Kai M. A. (2016) Nonnative species in British Columbia eelgrass beds spread via shellfish aquaculture and stay for the mild climate, Estuaries and Coasts Published online: <missing location>

Maldonado, Gustavo Carvalho; Skinner, Luis Felipe (2016) Differences in the distribution and abundance of Teredinidae (Mollusca: Bivalvia) along the coast of Rio de Janeiro state, Brazil, Brazilian Journal of Oceanography 64(4): Published online

Mao, Yangli; Gao, Tianxiang; Yanagimoto, Takashi; Xiao, Yongshuang (2011) Molecular phylogeography of Ruditapes philippinarum in the Northwestern Pacific Ocean based on COI gene, Journal of Experimental Marine Biology and Ecology 407: 171-181

Marshall, W. L.; Bower, S. M.; Meyer, G. R. (2003) A comparison of the parasite and symbiont fauna of cohabiting native (Protothaca staminea) and introduced (Venerupis philippinarum and Nuttalia obscurata) clams in British Columbia., Journal of Shellfish Research 22(1): 185-192

Meyer, John J.; Byers, James E. (2005) As good as dead? Sublethal predation facilitates lethal predation on an intertidal clam, Ecology Letters 8: 160-166

Mikkelsen, Paula M.; Bieler, Rüdiger; Kappner, Isabella; Rawlings, Timothy A. (2006) Phylogeny of Veneroidea (Mollusca: Bivalvia) based on morphology and molecules, Zoological Journal of the Linnean Society 148: 439-521

Mistri, Michele (2004) Predatory behavior and preference of a successful invader, the mud crab Dyspanopeus sayi (Panopeidae), on its bivalve prey., Journal of Experimental Marine Biology and Ecology 312: 385-398

Mortensen, Stein H.; Strand, Oivind (2000) Releases and recaptures of Manila clams (Ruditapes philippinarum) introduced to Norway, Sarsia 85: 89-91

Munroe, Daphne; Mckinley, R. Scott (2007) Effect of predator netting on recruitment and growth of Manila Clams (Venerupis philippinarum) on soft substrate intertidal plots in British Columbia, Canada, Journal of Shellfish Research 26(4): 1035-1044

Nichols, Frederic H.; Thompson, Janet K. (1985a) Time scales of change in the San Francisco Bay benthos., Hydrobiologia 129: 121-138

Nichols, Frederic H.; Cloern, James E.; Luoma, Samuel N. (1986) The modification of an estuary., Science 231: 567-573

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.

Nunes, Paulo, A. L. D.; Markandya, Anil (2008) Economic value of damage caused by marine bio-invasions: Lessons from two European case studies., ICES Journal of Marine Science 65: 775-780

Occhipinti Ambrogi, A. (2001) Transfer of marine organisms: a challenge to the conservation of coastal biocoenoses, Aquatic Conservation: Marine and Freshwater Ecosystems 11: 243-251

Occhipinti Ambrogi, Anna (2000) Biotic invasions in a Mediterranean lagoon., Biological Invasions 2: 165-176

Otero, M.; Cebrian, E.; Francour, P.; Galil, B.; Savini, D. (2013) <missing title>, International Union for Conservation of Nature, Malaga, Spain. Pp. 136

Palacios, Kelly C.; Ferraro, Stephen P. (2003) Green crab consumption rates on and prey preferences among four bivalve prey species, Journal of Shellfish Research 22(3): 265-271

Pederson, Judith and 6 authors (2011) Climate change and non-native species in the North Atlantic, ICES Cooperative Reseach Report 310: 174-190

Ponurovsky, S. K.; Yakolev, Yu M. (1992) The reproductive biology of the Japanese Littleneck Tapes philippinarum (A. Adams and Reeve 1850) (Bivalvia: Veneridae), Journal of Shellfish Research 11(2): 265-277

Pranovi, Fabio; Da Ponte, Filippo; Torricelli, Patrizia (2008) Historical changes in the structure and functioning of the benthic community in the lagoon of Venice., Estuarine, Coastal and Shelf Science 76: 753-764

Queiros, Ana de Moura; Hiddink, Jan Geert; Johnson, Gareth; Cabral, Henrique Nogueira; Kaiser, Michel Joseph (2011) Context dependence of marine ecosystem engineer invasion: Impacts on benthic ecosystem functioning, Biological Invasions 13: 1059-1075

Ranasinghe, J. Ananda and 6 authors. (2005) The prevalence of non-indigenous species in southern California embayments and their effects on benthic macroinvertebrate communities, Biological Invasions 7: 679-686

Riggs, Sharon R. (2011) <missing title>, Padilla Bay NERR, Padilla Bay WA. Pp. 5

Robinson, April; Cohen, Andrew N.; Lindsey, Brie; Grenier, Letitia (2011) Distribution of macroinvertebrates across a tidal gradient, Marin County, California, San Francisco Estuary and Watershed Science 9(3): published online

Ruesink, J. L. and 6 authors (2014) Spatio-temporal recruitment variability of naturalized Manila clams (Ruditapes philippinarum) in Willapa Bay, Washington, USA, Fisheries Research 151: 199-204

Ruesink, J. L.; Freshley, N.; Herrold, S.; Trimble, A. C.; Patten, K. (2014) Influence of substratum on non-native clam recruitment in Willapa Bay, Washington, USA, Journal of Experimental Marine Biology and Ecology 459: 23-30

Ruesink, J. L.; Feist, B. E.; Harvey, C. J., Hong, J. S.; Trimble, A. C.; Wisehart , L. M. (2006) Changes in productivity associated with four introduced species: ecosystem transformation of a ‘pristine’ estuary., Marine Ecology Progress Series 311: 203-215.

Ruiz, Gregory; Geller, Jonathan (2021) Spatial and temporal analysis of marine invasions: supplemental studies to evaluate detection through quantitative and molecular methodologies, Marine Invasive Species Program, California Department of Fish and Wildlife, Sacramento CA. Pp. 153 ppl.

Sagrista, Elena; Dufort, Merce; Azvedo, Carlos (1996) Ultrstructural data on the life cycle of the parasite Perkinsus atlanticus (Apicomplexa) on the clam Ruditapes philippinarum, in the Mediterranean, Scientia Marina 60(2-3): 283-288

Sakamaki, Takashi; Richardson, John S. (2008) Effects of small rivers on chemical properties of sediment and diets for primary consumers in estuarine tidal flats, Marine Ecological Progress Series 360: 13-24

Shin, Yun-Kyong; Kim, Yoon; Chung, Ee-Yung; Hurl, Sung-Bum (2000) Temperature and salinity tolerance of the Manila Clam, Ruditapes philippinarum, Journal of the Korean Fisheries Society 33(3): 313-318

Sladonja, Barbara; Bettoso, Nicola; Zentilin, Aurelio Tamberlich, Francesco; Acquavita, Alessandro (2011) Aquaculture and the Environment - A Shared Destiny, InTech, Rijeka, Croatia. Pp. 51-78

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

Stiger-Pouvreau, Valérie; Thouzeau, Gérard (2015) Marine species introduced on the French Channel-Atlantic coasts: a review of main biological invasions and impacts, Open Journal of Ecology, 5: 227-257

Streftaris, N.; Zenetos, A. (2006) Alien marine species in the Mediterranean - The 100 ‘worst invasives’ and their impact., Mediterranean Marine Science 7(1): 87-118

Talley, Drew M.; Talley, Theresa Sinicrope; Blanco, Alexander (2015) Insights into the establishment of the Manila Clam on a tidal flat at the southern end of an introduced range in Southern California, USA, PLOS ONE 10(3): e0118891

Tsai, Chaochung; Yang, Sylvia; Trimble, Alan C.; Ruesink, Jennifer L. (2010) Interactions between two introduced species: Zostera japonica(dwarf eelgrass) facilitates itself and reduces condition of Ruditapes philippinarum (Manila clam) on intertidal flats, Marine Biology 157: 1929-1936

2002-2021 Invertebrate Zoology Collections Database. <missing description>

Utting, S. D.; Spencer, B. E. (1992) Introductions of marine Bivalvia Mollusca into the United Kingdom, International Council for Exploration of the Marine Science Symposium 194: 84-91

Wallentinus, Inger; Nyberg, Cecilia D. (2007) Introduced marine organisms as habitat modifiers., Marine Pollution Bulletin 55: 323-332

2013 Hardshell Clams. http://wdfw.wa.gov/fishing/shellfish/clams/

Wasson, Kerstin; Zabin, C. J.; Bedinger, L.; Diaz, M. C.; Pearse J. S. (2001) Biological invasions of estuaries without international shipping: the importance of intraregional transport, Biological Conservation 102: 143-153

Weinersmith, Kelly L.; Colombano, Denise D.; Bibian, Andrew J.; Young, Matthew J.; Sih, Andrew J.; Conrad, Louise (2019) Diets of Largemouth Bass (Micropterus salmoides) in the Sacramento-San Joaquin Delta, San Francisco Estuary and Watershed Science 17: Published online

Whiteley, Jonathan; Bendell-Young, Leah (2007) Ecological implications of intertidal mariculture: observed differences in bivalve community structure between farm and reference sites, Journal of Applied Ecology 44: 495-505

Wonham, Marjorie J.; Carlton, James T. (2005) Trends in marine biological invasions at local and regional scales: the Northeast Pacific Ocean as a model system, Biological Invasions 7: 369-392

Yap, Wilfredo G. (1977) Population biology of the Japanese little-neck clam, Tapes philippinarum, in Kaneohe bay, Oahu, Hawaiian Islands, Pacific Science 31(3): 323-244