Mytilicola orientalis

Invasion History

First Non-native North American Tidal Record: 1938
First Non-native West Coast Tidal Record: 1938
First Non-native East/Gulf Coast Tidal Record:

---

General Invasion History:

Mytilicola orientalis is a parasitic copepod known from oysters (Crassostrea gigas, Pacific Oyster; Ostrea lurida, Olympia Oyster) and mussels (Mytilus crassitesta, M. edulis, M. trossulus, M. californianus) (Grizel 1985; Goater and Weber 1996). It also parasitizes clams (Protothaca staminea, Pacific Littleneck; Venerupis philippinarum, Japanese Littleneck), and the gastropod Crepidula fornicata (Rankin 1943, cited by Carlton 1979; Bower et al. 1992). It was described in 1935 from the Seto Inland Sea, Japan, from the bivalves C. gigas (Pacific Oyster) and M. crassitesta (the Asian Black Mussel) (Mori 1935, cited by Odlaug 1946). It has been introduced to Western North America from Morro Bay, California to British Columbia (Bernard 1969; Quayle 1969; Carlton 1979) and the Northeast Atlantic from France (Grizel 1985) to Ireland (Steele and Mulcahy 2001), the Netherlands (Stock 1993), and the French Mediterranean Coast (Clanzig 1989).

North American Invasion History:

Invasion History on the West Coast:

Mytilicola orientalis was first reported from North American waters in 1938 from Willapa Bay, Washington (WA) in Crassostrea gigas (Wilson 1938; cited by Carlton 1979). By 1943, it was reported from Puget Sound, WA (Rankin 1943, cited by Carlton 1979; Odlaug 1946). Its pattern of spread is difficult to discern and it was probably introduced to many locations with early plantings of Pacific Oysters around 1902, and not recognized until after the species was described. This parasite has been found in cultured oysters in Morro Bay, Elkhorn Slough, Tomales Bay, and Drakes Estero, California; and Yaquina Bay, Oregon (Hedgpeth 1962, cited by Carlton 1979; Chew 1965; Katkansky et al. 1967; Katkansky and Warner 1974, cited by Carlton 1979). In San Francisco and Humboldt Bays, it was found in Olympia Oysters (O. lurida) and mussels (Mytilus spp.) (Chew et al. 1965, Katkansky et al. 1967, Bradley and Siebert 1978, all cited by Carlton 1979). In southern British Columbia waters, M. orientalis is widespread in the Strait of Georgia and in Barkley Sound on the western side of Vancouver Island, in C. gigas, M. trossulus, and V. phillipinarum (Quayle 1969; Carlton 1979; Bower et al. 1992; Goater and Weber 1996).

Invasion History on the East Coast:

Mytilicola orientalis was first collected in European waters in 1977, in the Bay of Arcachon, France, on the Bay of Biscay (Goulletquer et al. 2002). In 1979, it was found in Marennes-Oleron, also on the Bay of Biscay (Goulletquer et al. 2002) and in the Mediterranean, in the Thau Lagoon, Sette, France (Clanzig 1989). All of these areas are extensively used for Pacific Oyster culture.

---

Description

The larval nauplius and copepodite stages of Mytilicola orientalis are planktonic, but the adults settle inside the intestine of a bivalve, where they metamorphose into greatly modified sedentary wormlike forms, with their appendages greatly reduced (Grizel 1985; Goater and Weber 1996). The adult female is 10 to 12 mm in length, and 1.33 mm wide at the largest section. The head is separate from the thorax. The antennules have four segments; the antennae have two. The antennae are modified into hooks used to cling to the host's tissue. The thorax consists of five segments with triangular lateral extensions. The genital segment is fused with the thoracic segments. The female produces paired egg sacs about 7 mm length, containing approximately 200 eggs. The abdomen is narrower than the genital segment and ends in two triangular outgrowths (Grizel 1985; Fisheries and Oceans Canada 2009).

The development of M. orientalis is unknown, but is probably similar to that of M. intestinalis, which consists of 2 nauplius stages, 5 copepodite stages, and a pre-adult stage, before metamorphosis into the parasitic adult (Gee and Davey 1986).

---

Taxonomy

Ecology

General:

Mytilicola orientalis is a parasitic copepod, capable of infecting a wide range of bivalve molluscs. Its most common host is the Pacific Oyster (Crassostrea gigas), but it is known from Ostrea lurida (Olympic Oyster), O. edulis (European Oyster), Mytilus coruscus (Japanese Black Mussel), M. edulis (Blue Mussel), M. galloprovincialis (Mediterranean Mussel), M. trossulus (Bay Mussel), M. californianus (California Mussel), Protothaca staminea (Pacific Littleneck), Venerupis philippinarum (Japanese Littleneck), and the gastrood Crepidula fornicata (Common Atlantic Slippersnail) (Rankin 1943, cited by Carlton 1979; Grizel 1985; Bower et al. 1992; Goater and Weber 1996). The wormlike adult female and male mate inside the host's intestine. The female produces paired egg sacs which hatch into naupli.

The life cycle of M. orientalis has not been studied, but in the similar M. intestinalis, there are two nauplius stages, and 5 copepodite stages, all non-feeding. The planktonic stages are filtered out by the bivalve, and remain within, developing into parasitic adults (Gee and Davies 1986). Patterns of infection suggest that dispersal distance in mussel beds is usually short, because the intense filtration of the bivalves remove the larvae from the water column. The number of copepods per mussel increases with mussel size, but decreases with tidal height, probably because of less time for infection (Goater and Weber 1996).

Food:

Crassostrea gigas; other bivalves

Trophic Status:

Parasite

Paras

---

Habitats

General Habitat	Oyster Reef	None
General Habitat	Marinas & Docks	None
General Habitat	Rocky	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Tidal Range	Low Intertidal	None
Tidal Range	Mid Intertidal	None
Vertical Habitat	Epibenthic	None

---

---

Tolerances and Life History Parameters

Minimum Reproductive Salinity	9.6	~50% hatching (Brenner et al. 2019)
Maximum Length (mm)	12	Female (Grizel 1985)
Broad Temperature Range	None	Cold temperate-Warm temperate
Broad Salinity Range	None	Mesohaline-Euhaline

General Impacts

The parasitic copepod Mytilicola orientalis infects oysters, mussels, and clams, including such commercially important species as the Pacific Oyster (Crassostrea gigas), Olympic Oyster (Ostrea lurida), European Oyster (O. edulis), Blue Mussel (Mytilus edulis). Impacts of parasitism on oysters appear to be mostly nonlethal, including local damage to intestinal tissue, and decreased condition factors (increased water, decreased fat content) (Odlaug 1946; Bernard 1969; Grizel 1985; Steele and Mulcahy 2001; Fisheries and Oceans Canada 2009). The extent of damage to mussels is unclear, but heavy infections can lead to mortality (Fisheries and Oceans Canada 2009). This parasite was included on a list of the '100 Worst Invaders' in the Mediterranean Sea (Streftaris and Zenetos 2006).

Economic Impacts

Fisheries: Parasitism by Mytilicola orientalis rarely kills oysters, but can lower their condition factor (increased water and decreased fat content), affecting the perceived quality of the oysters (Odlaug 1946; Grizel 1985; Fisheries and Oceans Canada 2009).

Ecological Impacts

Parasitism: Infection by Mytilicola orientalis appears to rarely result in mortality of oysters, but tissue damage to intestinal tissue and scar formation can reduce the efficiency of digestion, and contributes to decreased condtion factor (increased water content, decreased fat) (Odlaug 1946; Katkansky et al. 1967; Grizel 1985; Fisheries and Oceans Canada 2009). These impacts were variable with geography and season (Deslou-Paoli 1981, cited by Fisheries and Oceans Canada 2009). In Ireland, infection by M. orientalis did not directly affect health or quality of Crassostrea gigas, but was associated with increased infestations by shell-boring Polydora spp. (Steele and Mulcahy 2001).

---

Regional Impacts

NEP-IV	Puget Sound to Northern California		Ecological Impact	Parasitism
Infection with M. orientalis resulted in reduced condition factor in Olympia Oyster (Ostrea lurida) in Willapa Bay (Oldaug 1946). Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967).
P270	Willapa Bay		Ecological Impact	Parasitism
Infection with M. orientalis resulted in reduced condition factor in Olympia Oyster (Ostrea lurida) in Willapa Bay (Oldaug 1946). Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967).
NEP-IV	Puget Sound to Northern California		Economic Impact	Fisheries
Infection resulted in reduced condition factor (increased water, reduced fat) in Olympia Oyster (Ostrea lurida) in Willapa Bay (Oldaug 1946). Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967).
P270	Willapa Bay		Economic Impact	Fisheries
Infection resulted in reduced condition factor(increased water, reduced fat) in Olympia Oyster (Ostrea lurida) in Willapa Bay (Oldaug 1946). Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967).
NEA-III	None		Ecological Impact	Parasitism
Parasitism by M. orientalis did not directly affect health or quality of Crassostrea gigas, but was associated with increased infections by Polydora spp (Steele and Mulcahy 2001),
P130	Humboldt Bay		Ecological Impact	Parasitism
Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967).
NEP-III	Alaskan panhandle to N. of Puget Sound		Ecological Impact	Parasitism
Reduced condition factor was reported in infected Pacific Oysters (Crassostrea gigas) in Hood Canal and Oyster Bay, Puget Sound (Katkansky et al. 1967). Highest infection rates in mussels (Mytilus trossulus) in Barkley Sound, British Columbia, were seen in sheltered, muddy areas near the low-tide mark (Goater and Weber 2009).
P290	Puget Sound		Ecological Impact	Parasitism
Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in the Hood Canal and Oyster Bay, Puget Sound. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967).
NEP-III	Alaskan panhandle to N. of Puget Sound		Economic Impact	Fisheries
Impacts of Mytilicola orientalis on cultured Pacific Oysters (Crassostrea gigas were considered insignificant by Bernard (1969). Reduced condition factor was reported in infected Pacific Oysters (Crassostrea gigas) in Hood Canal and Oyster Bay, Puget Sound Chew et al. 1965; Katkansky et al. 1967). Reduced condition factor (smaller body mass, higher water content, less fat) reduces the quality of oysters.
P130	Humboldt Bay		Economic Impact	Fisheries
Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967). Reduced condition factor (smaller body mass, higher water content, less fat) reduces the quality of oysters.
P210	Yaquina Bay		Ecological Impact	Parasitism
Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967).
P210	Yaquina Bay		Economic Impact	Fisheries
Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967). Reduced condition factor (smaller body mass, higher water content, less fat) reduces the quality of oysters.
P290	Puget Sound		Economic Impact	Fisheries
Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in the Hood Canal and Oyster Bay, Puget Sound. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967). Reduced condition factor (smaller body mass, higher water content, less fat) reduces the quality of oysters.
NEA-IV	None		Ecological Impact	Parasitism
Parastism of Crassostrea gigas (Pacific Oyster) by Mytilicola orientalis resulted in reduced condtion factor only in spring and fall, when oysters were stressed by low food availability or spawning (Deslou-Paoli 1981, cited by Fisheries and Oceans Canada 2009).
NEA-II	None		Ecological Impact	Parasitism
Mytilicola orientalis, on the coast of the Netherlands, infected Pacific Oysters (Crassostrea gigas at 2-43% frequency, but also were found in Blue Mussels (Mytilus edulis, 3-63%), Common Cockles (Cerastoderma edule, 2-13%), and Baltic Tellins (Macoma balthica, 6-7%) (Goedknegt et al. 2017a; Goedknegt et al. 2017b). The intensity of infection in M. edulis was strongly correlated with intensity in C. gigas, indicating transmission of the parasite between Pacific Oysters and native Blue Mussels (Goedknegt et al. 2017b). Stable isotope studies, in the Netherlands, show that M. orientalis gets much of its nutrition from tissues of its host mussel (Mytilus edulis, as well as from the ingested organic material, so that it is more of a parasite than a commensal (Goedknecht et al. 2018).
NEA-II	None		Ecological Impact	Competition
The parasitic copepod Mytilicola orientalis, introduced into the Wadden Sea (Sylt, Gernany) with Pacific Oysters (Magallana gigas) has infected native Blue Mussels (Mytilus edulis) and displaced its native parasite (Mytilicola intestinalis).  Mytilcola orientalis is less successful  than the native parasite at infecting mussels, but the high density of Pacific Mussels allows a highrate of spllover.  Also, aggergation of M. orientalis may interfere with mating of M. intestinalis , resultin in indirect competition (Feis et al. 2022)/
NEP-V	Northern California to Mid Channel Islands		Economic Impact	Fisheries
Reduced condition factor of oysters
WA	Washington		Ecological Impact	Parasitism
Infection with M. orientalis resulted in reduced condition factor in Olympia Oyster (Ostrea lurida) in Willapa Bay (Oldaug 1946). Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967)., Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in the Hood Canal and Oyster Bay, Puget Sound. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967).
WA	Washington		Economic Impact	Fisheries
Infection resulted in reduced condition factor(increased water, reduced fat) in Olympia Oyster (Ostrea lurida) in Willapa Bay (Oldaug 1946). Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967)., Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in the Hood Canal and Oyster Bay, Puget Sound. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967). Reduced condition factor (smaller body mass, higher water content, less fat) reduces the quality of oysters.
OR	Oregon		Ecological Impact	Parasitism
Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967).
OR	Oregon		Economic Impact	Fisheries
Reduced condition factor was also reported in infected Pacific Oysters (Crassostrea gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967). Reduced condition factor (smaller body mass, higher water content, less fat) reduces the quality of oysters.
CA	California		Ecological Impact	Parasitism
Reduced condition factor was also reported in infected Pacific Oysters (Magallana gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967).
CA	California		Economic Impact	Fisheries
Reduced condition factor of oysters Reduced condition factor was also reported in infected Pacific Oysters (Magallana gigas) in Humboldt, Yaquina, and Willapa Bays. However, no relation was seen between infection and mortality (Chew et al. 1965; Katkansky et al. 1967). Reduced condition factor (smaller body mass, higher water content, less fat) reduces the quality of oysters.

References

Ashelby, Christopher W. (2022) Tanaid in The Thames: Sinelobus vanhaareni Bamber, 2014 (Crustacea: Tanaididae) arrives in Britain, Cahiers de Biologie Marine 63(4): 377-383
DOI: 10.21411/CBM.A.FC8CA4E6

Bernard, F. R. (1969) The parasite Mytilicola orientalis in British Columbia, Journal of the Fisheries Research Board of Canada 26(1): 190-191

Boisset, Fernando; Ferrer-Gallego, P. Pablo (2015) Typification of the marine siphonous green algae Caulerpa prolifera (Bryopsidales,Chlorophyta), Phytotaxa 221(2): 148–156
https://doi.org/10.11646/phytotaxa.221.2.4

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

Brenner, Matthias; Schulze, Jona Fischer, Johanna; Wegner, K. Mathias (2021) First record of the parasitic copepod (Mytilicola orientalis Mori, 1935) in blue mussels (Mytilus spp.) of the Baltic Sea, BioInvasions Records 8(3): 623–632

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

Chew, K. K.; Sparks, A. K.; Katkansky, S. C. (1965) Preliminary results on the seasonal size distribution of Mytilicola orientalis and the effects of theis parasite on the condition of the Pacific Oyster Crassostrea gigas, Journal of the Fisheries Research Board of Canada 22(4): 1099-1101

Clanzig, Sylvain (1989) Invertebres d'introduction recente dans les lagunes mediterraneennes du languedoc-roussillon, Bulletin de la Societe Zoologique de France 114(3): 151-152

Coen, Loren D.; and 7 authors (2007) Ecosystem services related to oyster restoration., Marine Ecology Progress Series 341: 303-307

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

Elsner, Nikolaus O.; Jacobsen, Sabine; Thieldges, David W.; Reise, Karsten (2011) Alien parasitic copepods in mussels and oysters of the Wadden Sea, Helgoland Marine Research 65: 299-307

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 2009 Synopsis of infectious diseases and parasites of commercially exploited shellfish: <i>Mytilicola orientalis</i> (red worm) of oysters. <missing URL>



Francisco, Claire J.; Hermida, Margarida A.; Santos, Maria J. (2010) Parasites and symbionts from Mytilus galloprovincialis (Lamark, 1819) (Bivalves: Mytilidae) of the Aveiro estuary Portugal, Journal of Parasitology 96(1): 200-205

Gagnon, Karine; Herlevi, Heidi; Wikström, Jenny; Nordström, Marie C.; , Salo, Tiina; Salovius-Laurén, Sonja; Rinne, Henna (2021) Distribution and ecology of the recently introduced tanaidacean crustacean Sinelobus vanhaarenI Bamber, 2014 in the northern Baltic Sea, Aquatic Invasions 17: Published online

Galil, Bela S. (2000) A sea under siege: alien species in the Mediterranean., Biological Invasions 2: 177-186

Gee, J. M.; Davey, J. T. (1986) Stages in the life history of Mytilicola intestinalis Steur, a copepod parasite of Mytilus edulis L., and the effect of temperature on their rate of development, Journal du Conseil Internationale d Exploration de la Mer 42: 254-264

Goater, Cameron P.; Weber, Amy E. (1996) Factors affecting the distribution and abundance of Mytilicola orientalis (Copepoda) in the mussel Mytlilus trossulus in Barkeley Sound, B. C., Journal of Shellfish Research 15(3): 681-684

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

Grizel, H. (1985) Mytilicola orientalis Mori, parasitism, ICES Identification Sheets for diseases and parasites [Fishes, Crustaceans, Mollusks) 20: 1-4

Holmes, J. M. C.; Minchin, Dan (1995) Two exotic copepods imported into Ireland with the Pacific oyster Crassostrea gigas (thunberg), Irish Naturalists' Journal 25(1): 17-20

Jeffrey A. Sibaja-Cordero; Garcia-Mendez, Kimberly; Troncoso, Jesús S. (2013) Additions to the mollusk checklist of Cocos Island National Park, Costa Rica (Eastern Tropical Pacific), Iberus 31(2): 127-163

Katkansky, Stanley C.; Sparks, Albert K.; Chew, Kenneth, K.h (1967) Distribution and effects of the endoparasitic copepod Mytilicola orientalis, on the Pacific coast, Proceedings of the National Shellfisheries Association 57: 50-58

Katkansky, Stanley C.; Warner, Ronald W. (1970) Sporulation of a haplosporidan in a Pacific oyster (Crassostrea gigas) in Humboldt Bay, California, Journal of the Fisheries Research Board of Canada 27(7): 1320-1321

Kim, Il-Hoi (2004) Poecilostomatoid copepods associated with bivalves in Korea and their distribution., Zoological Studies 43(2): 187-192

Kocak, Ferah (2023) Alien bryozoan species along the Aegean coast of Turkey, Cahiers de Biologie Marine 64: 137-151
DOI: 10.21411/CBM.A.B3634AD9

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

Minchin, Dan; Gollasch, Stephan (2002) Vectors - how exotics get around., In: Leppakoski, E.; Gollasch, S.; Olenin, S.(Eds.) Invasive aquatic species of Europe: distribution, impacts and management.. , Dordrecht/ Boston/ London. Pp. 183-192

Nydam, Marie L.; Stefaniak, Lauren M.; Lambert, Gretchen; Counts, Bailey; · López?Legentil, Susanna (2022) Dynamics of ascidian?invaded communities over time, Biological Invasions 24: 3489–3507
https://doi.org/10.1007/s10530-022-02852-0

Odlaug, Theron O. (1946) The effect of the copepod, Mytilicola orientalis upon the Olympia Oyster, Ostrea lurida., Transactions of the American Microscopical Society 65(4): 311-317

Quayle, D. B. (1969) Pacific oyster culture in British Columbia, Canadian Fisheries Research Board Bulletin 169: 1-192

Rosenfield, Aaron, Kern, Frederick G. (1979) <missing title>, Massachusetts Institute of Technology Press, Cambridge. Pp. 165-189

Steele, S.; Mulcahy, M. F. (2001) Impact of the copepod Mytilicola orientalis on the Pacific oyster Crassostrea gigas in Ireland., Diseases of Aquatic Organisms 47: 145-149

Stock, Jan H. (1993) Copepoda (Crustacea) associated with commercial and non-commercial Bivalvia in the East Scheldt, The Netherlands, Crustaceana 63(1): 61-64

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

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

Van den Brink, A. M.; Wijsman, J. W. M. (2010) <missing title>, ]IMARES - Institute for Marine Resources & Ecosystem Studies], Netherlands. Pp. 1-47

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

Wells, Harry W.; Wells, Mary Jane; Gray, I. E. (1967) Marine Sponges of North Carolina, Journal of the Elisha Mitchell Scientific Society 76(2): 200-245

White, C. ;Snodgrass, J. (1988) <missing title>, Office of Natural Resources Management, Brevard County, Titusville FL. Pp. 12 pp.

---