Invasion History

First Non-native North American Tidal Record: 1943
First Non-native West Coast Tidal Record: 1973
First Non-native East/Gulf Coast Tidal Record: 1943

General Invasion History:

Sphaeroma walkeri was described from the Gulf of Mannar, Sri Lanka, and subsequently (1950s-1960s) from the Bay of Bengal and Arabian Sea coasts of India (Carlton and Iverson 1981). Range extensions westward into Pakistan (California Academy of Sciences 2015), the Strait of Hormuz (Khalaji-Pirbalouty 2014), the Persian Gulf (US National Museum of Natural History 2007), the Gulf of Suez (Omer-Cooper 1927, cited by Carlton and Iverson 1981), and eastward to Malaysia and the Strait of Malacca (Rai Singh and Sasekumar 1996), probably represent a mixture of newly discovered natural populations and ship transport.

Outside of the northern Indian Ocean, Sphaeroma walkeri is clearly introduced to southern Africa (Stebbing 1917, cited by Carlton and Iverson 1981), Western Australia (Montelli and Lewis 2008), southern China (Kussakin and Malyutina 1993), and eastern Australia (Iredale et al. 1992, cited by Carlton and Iverson 1981). This isopod has now colonized warm-temperate to tropical waters in many parts of the world, including the Mediterranean Sea (Fox 1927, cited by Carlton and Iverson 1981; Jacobs 1987), the east coast of North and South America from Florida to Brazil (Miller 1968; Carlton and Iverson 1981), the Northwest coast of Africa (Jacobs 1987), Southern California, and Hawaii (Carlton and Iverson 1981). This isopod has been found in large numbers in crevices on ship hulls, pilings, and buoys (Miller 1968; Carlton and Iverson 1981; Mak et al. 1985); and as an occasional swimmer, it may occur in ballast water, too.

North American Invasion History:

Invasion History on the West Coast:

Sphaeroma walkeri was first collected on the West Coast in 1973 in San Diego Bay, California (CA) (Carlton and Iverson 1981). In 1973-1976, it was found throughout much of the bay in fouling communities on pilings, floats and small boats, crevices of intertidal rocks, empty barnacle shells, and burrows made by gribbles (Limnoria spp). At some sites, it exceeded native sphaeratomid isopods (Paracerceis sculpta, Paradella dianae) in abundance. It was not found in adjacent Mission Bay. Sphaeroma walkeri has been reported from San Francisco Bay, as appearing in the 1990s (Carlton 2000; Fairey et al. 2002), but no information is available on its distribution or establishment. It has not been reported in recent surveys in southern California or San Francisco Bay (Cohen et al. 2002; Cohen et al. 2005; Cohen and Chapman 2005; Foss 2009). We consider this species to be established in Southern California, but treat its establishment status in San Francisco Bay as 'unknown'.

Invasion History on the East Coast:

Sphaeroma walkeri was first collected on the East and Gulf coasts in 1943, during a study of fouling on buoys in US coastal waters (Miller 1968: Carlton and Iverson 1981). During this survey, S. walkeri was collected on both coasts of Florida, at Ponce de Leon Inlet, near Daytona Beach on the Atlantic Coast (USNM 233250, US National Museum of Natural History 2007), and the Egmont Channel, Tampa Bay and New Pass, Sarasota Bay on the Gulf Coast (Miller 1968). Subsequently, this isopod was collected on the Atlantic Coast of Florida from Fernandina Beach, near the Georgia border, to Virginia Key, Biscayne Bay including many sites in the Indian River Lagoon (Carlton and Iverson 1981; Nelson and Demetriades 1992; Kensley et al. 1995; US National Museum of Natural History 2015). On the Gulf Coast of Florida, we have no definite records beyond the Tampa and Sarasota Bay records from 1943 (Miller 1968), but assume that it is established. In 1978, S. walkeri was collected on jetties and rocks at South Padre Island, Texas (Clark and Robertson 1982). The extent of this isopod's range in the Gulf of Mexico is uncertain.

Invasion History in Hawaii:

Sphaeroma walkeri was collected in Hilo harbor, during the broad scale 1943 survey of fouling on buoys throughout the United States (Miller 1968). In 1961, it was found in Hanamaula Bay, Kauai (Carlton and Iverson 1981). It has also been collected in Pearl Harbor and Kaneohe Bay, Oahu (in 1976-1980, Carlton and Eldredge 2009).

Invasion History Elsewhere in the World:

Sphaeroma walkeri is one of the world's most widespread isopod invaders. As noted above, the extent of its native range in the Indian Ocean is unclear. We treat occurrences at the Red Sea mouth of the Suez Canal, in the Persian Gulf, the western Arabian Sea, and the Malaysian Peninsula as cryptogenic (Carlton and Iverson 1981; Rai Singh and Sasekumar 1996; Ghani and Mohammed 2001; Khalaji-Pirbalouty and Wagele 2010). This isopod was transported to some distant ports very early in the 20th century: Durban, South Africa (Stebbing 1917 cited by Carlton and Iverson 1981); and Sydney, Australia (in 1927, Iredale et al. 1932 cited by Carlton and Iverson 1981). At other Indo-Pacific ports, S. walkeri was discovered much later: Inhambane, Mozambique (in 1954, Barnard 1955; cited by Carlton and Iverson 1981); Townsville, Queensland, Australia (in 1967, USNM 125946, US National Museum of Natural History 2015); Hainan Island, China (in 1958, Kussakin and Malyutina 1993); and Cockburn Sound, Western Australia (in 2003, Montelli and Lewis 2008).

The spread and/or discovery of Sphaeroma walkeri into the Mediterranean shows a similarly spotty pattern, with an early colonization of the Suez Canal, but with records scattered in space and time further west. Early records from Suez include: Lake Timsah and Port Said, Egypt (in 1924, Fox 1927, cited by Carlton and Iverson 1981). However, records outside Egypt were reported much later: Haifa, Israel in 1972 (Glynn 1972, cited by Galil 2008); Alicante, Spain in 1981 (Jacobs 1987); Turunc, Turkey, Aegean Sea in 1995 (Kirkim et al. 2006); Tunisia, Lagoon of Tunis, in 2003 (Ben Amor et al. 2010), with large gaps in its known Mediterranean range. It was collected in the Black Sea, in Romania in 2004 (Skolka and Preda 2010), but was called 'casual' and not established, there. In the Eastern Atlantic, S. walkeri was found at Nouadhibou, Mauritania, in 1978, and Tangier, Morocco, in 1982 (Jacobs 1987).

In the Western Atlantic, it was collected in 1942 or 1943 in San Juan Harbor, Puerto Rico (Menzies and Glynn 1968). Later Caribbean records were from Nuevitas Bay, Cuba in 1994 (USNM 280039, US National Museum of Natural History 2007) and Isla Margarita, Venezuela in 2004 (Gutiérrez 2010). In Brazilian waters, it was found on the Ihla do Mel (Parana) in 1953 (Loyala e Silva 1960, cited by Carlton and Iverson 1981), and subsequently at many sites in southern Brazil from Ilha do Mel (26°S) to Itaipu Beach (23ºS) (Pires 1982). It was also collected at Fortaleza (Ceara, 4ºS) in northern Brazil, in 1958 (Loyala e Silva 1960, cited by Carlton and Iverson 1981).


Sphaeroma walkeri has a compact, convex, elliptical body, about twice as long as wide. The anterior edge of the head has a small, but visible rostral process, flanked by two blunt projections and bordered by two large eyes. Peraeonites 2-7 have the coxal sutures clearly visible in lateral view, and each has a row of tubercles, which increase in size and density posteriorly. The pleon segments also bear rows of tubercles. The peraeaonites are roughly equal in width, except for Peraeonite 1, which is somewhat broader than the others. The pleotelson has 4 longitudinal rows of large tubercles and irregular lateral rows. There are also 3 large tubercles on the endopodites of the uropods.

Antenna 1 has a flagellum of 13-16 segments and extends to the posterior edge of Peraeonite 1. Antenna 2's flagellum has 14-20 segments, and passes the posterior edge of Peraeonite 2. Peraeonites 2-7 each bear a broad transverse ridge. Pereiopods 1-3 bear dense plumose setae on the upper (anterior) surface of segments 3-4, a possible adaptation for filter-feeding. The pleon has several tubercles. The outer edges of the exopods of the uropods each bear 5-7 prominent teeth. The apical edge of the telson is crenated (scalloped). Adult males are 6-16 mm long, while females are smaller. We have not found descriptions of coloration, but photographs show this isopod being tan, with dark-brown dots. Description based on: Harrison and Holdich 1984, Jacobs 1987, Brusca et al. 2007, Galil 2008, Ben Amor et al. 2010, Khalaji-Pirbalouty and Wägele 2010.


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Arthropoda
Subphylum:   Crustacea
Class:   Malacostraca
Subclass:   Eumalacostraca
Superorder:   Peracarida
Order:   Isopoda
Suborder:   Flabellifera
Family:   Sphaeromatidae
Genus:   Sphaeroma
Species:   walkeri


Potentially Misidentified Species

Sphaeroma quadridentatum
Sphaeroma quadridentatum is native to the Northwestern Atlantic, from Cape Cod to Texas. It inhabits intertidal zones and shallow-water fouling communities (Clark and Robertson 1982; Kensley and Schotte 1989).

Sphaeroma quoianum
Sphaeroma quoianum is native to the coasts of Australia and New Zealand, and introduced to the West Coast of North America from San Diego to Yaquina Bay, Oregon. This isopod is common in estuarine habitats, where it bores in rotten wood, salt-marsh peat, sandstone, and Styrofoam (Carlton 1979; Davidson et al. 2008).

Sphaeroma terebrans
Sphaeroma terebrans is probably native to the Indian Ocean, from Mozambique to India, Japan and Australia, and a very early introduction to the Atlantic, from South Africa to Ghana, and from Brazil to South Carolina. This isopod is a frequent woodborer in mangroves, driftwood, and ships' hulls, and is also known to burrow in marsh peat. It is euryhaline, occurring from freshwater to ~38 PSU (Harrison and Holdich 1984; Kensley 1978; Kensley and Schotte 1989; Carlton and Ruckelshaus 1997).



Sphaeroma walkeri has separate sexes and internal fertilization. Its young are brooded by the female, and development is direct. In the Tunis Lagoon, Tunisia, populations are most abundant in summer, but in the Indian River Lagoon, Florida, peak densities were seen in summer and late winter-early spring (Ben Amor et al. 2010; Nelson and Demetriades 1992). Reported sizes for adults range from 6 to 16 mm (Harrison and Holdich 1984).

Sphaeroma walkeri inhabits sheltered marine coastal waters in warm-temperate to tropical climates. It occurs at a temperature range of at least 12 to 30 C and a salinity range of 24 to 40+ PSU (Carlton and Iverson 1981; Nelson and Demetriades 1992). Sphaeroma walkeri is not a substrate-borer, but is a crevice-dweller, living in and under rocks, wood, and in fouling communities on jetties, pilings, floats, buoys, and vessel hulls (Miller 1968; Carlton and Iverson 1979; Harrison and Holdich 1984; Nelson and Demetriades 1992). In the Indian River Lagoon, Florida, S. walkeri was very abundant in reefs created on jetties by the sabellarid polychaete Phragmatopoma lapidosa (Nelson and Demetriades 1992). In the Tunis Lagoon, Tunisia, it was more abundant in and among sponges (Ben Amor et al. 2010). The feeding habits of this species are unknown; however Loyola e Silva (1980, cited by Carlton and Iverson 1981) suggested that their likely diet is algae and associated microfauna.


Vegetation and associated microorganisms

Trophic Status:




General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatCoarse Woody DebrisNone
General HabitatVessel HullNone
General HabitatCanalsNone
General HabitatMangrovesNone
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Tidal RangeLow IntertidalNone
Vertical HabitatEpibenthicNone

Tolerances and Life History Parameters

Minimum Temperature (ºC)12Field data, San Diego Bay (Carlton and Iverson 1981)
Maximum Temperature (ºC)30Field data, Sebastian River Inlet, Florida (Nelson and Demetriades 1992);
Minimum Salinity (‰)24Field data, Sebastian Inlet, Florida (Nelson and Demetriades 1992). Salinities of 17 and 8.5 PSU were lethal (George 1967).
Maximum Salinity (‰)40Upper range, Persian Gulf, Red Sea, Eastern Mediterranean
Minimum Length (mm)6Harrison and Holdich 1984; Jacobs 1987; Brusca et al. 2007; Khalaji-Pirbalouty and Wägele 2010)
Maximum Length (mm)16Ben Amor et al. 2010
Broad Temperature RangeNoneWarm temperate-Tropical
Broad Salinity RangeNonePolyhaline-Euhaline

General Impacts

Sphaeroma walkeri has been found at high densities in some of its introduced habitats, including those in Florida (Nelson and Demetriades 1992) and southern California (Carlton and Iverson 1981), but its impacts on coastal biota are unknown.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
CIO-II None 0 Native Estab
CIO-III None 0 Native Estab
CIO-I None 0 Native Estab
AG-3 None 1956 Crypto Estab
AG-1 None 2006 Crypto Estab
IP-1 None 1973 Crypto Estab
RS-3 None 1924 Crypto Estab
MED-V None 1924 Def Estab
EA-IV None 1954 Def Estab
WA-V None 1917 Def Estab
AUS-XII None 1967 Def Estab
AUS-X None 1927 Def Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 1943 Def Estab
CAR-IV None 1943 Def Estab
SA-IV None 1958 Def Estab
SA-II None 1953 Def Estab
NEP-VI Pt. Conception to Southern Baja California 1973 Def Estab
SP-XXI None 1943 Def Estab
NWP-2 None 1958 Def Estab
CAR-VII Cape Hatteras to Mid-East Florida 1943 Def Estab
S190 Indian River 1943 Def Estab
P020 San Diego Bay 1973 Def Estab
S175 _CDA_S175 (Nassau) 1965 Def Estab
S183 _CDA_S183 (Daytona-St. Augustine) 1965 Def Estab
S200 Biscayne Bay 1974 Def Estab
G060 Sarasota Bay 1943 Def Estab
G070 Tampa Bay 1943 Def Estab
CAR-II None 1994 Def Estab
NWP-3a None 2001 Def Estab
G330 Lower Laguna Madre 1978 Def Estab
WA-I None 1978 Def Estab
MED-II None 1981 Def Estab
MED-VI None 1995 Def Estab
P090 San Francisco Bay 2000 Def Unk
NEP-V Northern California to Mid Channel Islands 2000 Def Unk
S180 St. Johns River 1965 Def Estab
AUS-IV None 2003 Def Estab
MED-IX None 2004 Def Unk
MED-III None 2003 Def Estab
CAR-III None 2004 Def Estab
EAS-VI None 0 Crypto Estab
NEA-V None 2017 Def Estab
CAR-V None 1994 Def Estab
AUS-XI None 0 Def Estab
MED-IV None 2015 Def Estab
SA-III None 0 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


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Ben Amor, Khadija Ounifi; Salem, Mohamed Ben; Ben Souissi, Jamila (2010) Sphaeroma walkeri Stebbing,1905 (Crustacea, Isopoda, Sphaeromatidae) introduced and established in Tunisia waters, Rapport du Congress de la CIESM 39: 615

Bleile, Nadine; Thieltges, David W. 2021 Prey preferences of invasive (Hemigrapsus sanguineus, H. takanoi) and native (Carcinus maenas) intertidal crabs in the European Wadden Sea. <missing URL>

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Brusca, Richard C.; Coeljo, Vania R. Taiti, Stefano (2007) The Light and Smith Manual: Intertidal invertebrates from Central California to Oregon (4th edition), University of Calfiornia Press, Berkeley CA. Pp. 503-542

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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

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. (2000) Invasive species in a changing world., Island Press, Covelo, CA. Pp. 19-31

Carlton, James T.; Iverson, Ernest W. (1981) Biogeography and natural history of Sphaeroma walkeri Stebbing (Crustacea: Isopoda) and its introduction to San Diego Bay, California, Journal of Natural History 15: 31-48

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

Carlton, James T.; Ruckelshaus, Mary H. (1997) Nonindigenous marine invertebrates and algae of Florida, In: Simberloff, Daniel, Schmitz, Don C., Brown, Tom C.(Eds.) Strangers in Paradise: Impact and Management of Nonindigenous Species in Florida. , Washington, D.C.. Pp. 187-201

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

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

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

Cohen, Andrew N.; Moyle, Peter B. (2004) <missing title>, <missing publisher>, <missing place>. Pp. <missing location>

Davidson, Timothy M. (2008) Prevalence and distribution of the introduced burrowing isopod, Sphaeroma quoianum, in the intertidal zone of a temperate northeast Pacific estuary (Isopoda, Flabellifera), Crustaceana 81(2): 155-167

Emara, Ahmed; Belal, Aisha (2004) Marine fouling in Suez Canal, Egypt, Egyptian Journal of Aquatic Research 30A: 189-206

Fairey, Russell; Dunn, Roslyn; Sigala, Marco; Oliver, John (2002) Introduced aquatic species in California's coastal waters: Final Report, California Department of Fish and Game, Sacramento. Pp. <missing location>

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

Galil, Bella S. (2008) Sphaeroma walkeri Stebbing, 1905 (Crustacea: Isopoda: Sphaeromatidae) established on the Mediterranean coast of Israel., Memoirs of the Museum of Victoria 3(4): 443-444

George, R. Y. (1967) Proceedings of the Symposium on Crustacea, held at Ernakulam from January 12 to 15, 1965, Marine Biological Association of India, <missing place>. Pp. 1067-1073

Ghani, Naseem; Ali Qadeer Mohammad (2001) Sphaeroma walkeri, 1905 in the coastal waters of Karachi (North Arabian Sea), Online Journal of Biological Sciences 1(9): 871-872

Gutiérrez, Javier. A. (2010) [Marine isopods (Crustacea: Peracarida) of the coast of Isla de Margarita, Venezuela], Memoria de la Fundacion La Salle de Ciencias Naturales 173-174: 25-38

Harrison, K.; Ellis, J. P. (1991) The genera of the Sphaeromatidae (Crustacea: Isopoda): a key and distribution list, Invertebrate Taxonomy 5: 915-952

Harrison, K.; Holdich, D. M. (1984) Hemibranchiate sphaeromatids (Crustacea: Isopoda) from Queensland, Australia, with a world-wide review of the genera discussed, Zoological Journal of the Linnean Society 81: 275-387

Huang, Zongguo (Ed.), Junda Lin (Translator) (2001) Marine Species and Their Distributions in China's Seas, Krieger, Malabar, FL. Pp. <missing location>

Jacobs, B. J. M. (1987) A taxonomic revision of the European Mediterranean and NW African species generally placed in Sphaeroma Bosc 1802 (Isopoda: Flabellifera: Sphaeromatidae)., Zoologische Verhandelingen 238: 1-71

Kensley, Brian (1978) <missing title>, Trustees of the South African Musuem, Cape Town. Pp. <missing location>

Kensley, Brian; Nelson, Walter G.; Schotte, Marilyn (1995) Marine isopod biodiversity of the Indian River Lagoon, Florida, Bulletin of Marine Science 57(1): 136-142

Kensley, Brian; Schotte, Marilyn (1989) <missing title>, Smithsonian Institution Press, Washington, D.C.. Pp. <missing location>

Khalaji-Pirbalouty, Valiallah; Wägele, Johann-Wolfgang (2010) A new species and a new record of Sphaeroma Bosc, 1802 (Sphaeromatidae: Isopoda: Crustacea) from intertidal marine habitats of the Persian Gulf, Zootaxa 2631: 1-18

Kirkim, Fevzi; Ahmet Kocatas; Kataúan, Tuncer; Sezgün, Murat (2006) Contribution to the knowledge of the free-living isopods of the Aegean sea coast of Turkey, Turkish Journal of Zoology 30: 361-372

Kussakin, Oleg G.; Malyutina, Marina V. (1993) Sphaeromatidae (Crustacea: Isopoda: Flabellifera) from the South China Sea., Invertebrate Taxonomy 7: 1167-203

Lomonaco, Cecilia; Santos, Andre S.; Christoffersen, Martin l. (2011) Effects of local hydrodynamic regime on the individual’s size in intertidal Sabellaria (Annelida: Polychaeta: Sabellariidae) and associated fauna at Cabo Branco beach, north-east Brazil, Marine Biodiversity Records 4(e76): Published online

Mak, P. M. S.; Huang, Z. G.; Morton, B. S. (1985) Sphaeroma walkeri Stebbing (Isopoda, Sphaeromatidae) Introduced into and established in Hong Kong, Crustaceana 49(1): 75-82

Martín, A.; Díaz, Y. J. (2003) [The amphipod fauna (Crustacea: Amphipoda) of the coastal waters of eastern Venezuela], Boletin Insititute Espanol de Oceanografia 19(1-4): 327-344

Martín, Alberto; Díaz, Yusbelly J. Díaz (2007) [Biodiversity of peracarid curstaceans in the Rio Orinoco Delta, Venezuela, Revista Biologia Tropica 55(Suppl. 1): 87-102,

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Miller, Milton A. (1968) Isopoda and Tanaidacea from buoys in coastal waters of the continental United States, Hawaii, and the Bahamas (Crustacea), Proceedings of the United States National Museum 125(3652): 1-53

Montelli, Luciana; Lewis, John (2008) <missing title>, Maritime Platforms Division, Defence Science and Technology Organisation, Australia, Fishermans Bend, Victoria, Australia. Pp. 1-50

Morgan, David L.; Gill, ;Howard S.; Maddern, Mark G; Beatty. .; Stephen J. (2004) Distribution and impacts of introduced freshwater fishes in Western Australia, New Zealand Journal of Marine and Freshwater Research 38: 511-523

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

Nelson, Walter G.; Demetriades, Leandros (1992) Peracarids associated with Sabellariid worm rock (Phragmatopoma lapidosa) at Sebastian inlet, Florida, Journal of Crustacean Biology 12(4): 647-654

Pires, Ana Maria Setubal (1982) [Sphaeromatidae (Isopoda:Flabellifera) of the intertidal and shallow depths of the states of Sao Paulo and Rio de Janeiro, Boletim do Instituto Oceanográfico 31(2): 43-55

Rai Singh, Harinder; Sasekumar, A. (1996) Wooden panel deterioration by tropical marine wood borers, Estuarine, Coastal and Shelf Science 42: 755-769

Ramadan, Sh. E.; Kheirallah, A. M.; Abdel-salam, Kh. M. (2006) Marine fouling community in the Eastern harbour of Alexandria, Egypt compared with four decades of previous studies, Mediterranean Marine Science 7/2: 19-29

Ruiz, Gregory M.; Geller, Jonathan (2018) Spatial and temporal analysis of marine invasions in California, Part II: Humboldt Bay, Marina del Re, Port Hueneme, and San Francisco Bay, Smithsonian Environmental Research Center & Moss Landing Laboratories, Edgewater MD, Moss Landing CA. Pp. <missing location>

Santos, Cinthya S. G. (2007) Nereididae from Rocas Atoll (North-East, Brazil)., Arq. Mus. Nac., Rio de Janeiro 65(3): 369-380

Skolka, Marius; Preda, Cristina (2010) Alien invasive species at the Romanian Black Sea coast: present and perspectives, Travaux du Muséum National d’Histoire Naturelle «Grigore Antipa» 53: 443-467

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