Invasion History

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

General Invasion History:


North American Invasion History:


Bougainvillia muscus is a widely distributed hydrozoan, with a sessile asexual reproducing hydroid, and a pelagic sexually reproducing medusa..

The hydroids of Bougainvillia muscus are erect, and irregularly branched, with a single or multiple stalks, with a few, or with densely bushy branches. The surfaces of the stalks and branches are often densely covered with detritus. The branches are corrugated at the base, but not distinctly annulated. The hydranths have 10-18 tentacles, protuding from a rounded to conical hypostome. Gonophores (which bud off medusae), are pear-shaped, and are borne on stalks of variable length. Hydroid colonies vary from a few mm to 1200 mm. The hydranths can be pink, red, orange, or grayish purple, depending on food types (Schuchert 2007; Mills et al. 2007).

The medusa of Bougainvillia muscus is bell-shaped. Newly released medusae have a thin umbrella, with four radial canals leading from the manubrium to tentacle bulbs, each of which have two tentacles and two ocelli. Mature medusae have gonads growing around the manubrium, and two-six tentacles per bulb. The mamubrium bears four oral tentacles, which are each divided dichotomously two to four times. Adult medusae are 1-4 mm in height and width Schuchert 2007; Mills et al. 2007).

The distribution of B. muscus is confused by the presence of many similar related speces, and the potential for misidentification (Schuchert 2007). Most Mediterranean records may be actually B. nana (Denitto et al. 2007). However,


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Cnidaria
Class:   Hydrozoa
Subclass:   Hydroidolina
Order:   Anthoathecatae
Suborder:   Filifera
Family:   Bougainvilliidae
Genus:   Bougainvillia
Species:   muscus


Bougainvillia ramosa (Millard, 1975)
Eudendrium ramosum (Van Beneden, 1844)
Perigonymus muscus (Allman, 1863)
Perigonymus ramosus (Allman, 1863)

Potentially Misidentified Species

Bougainvillia multitentaculata
Abundant in British Columbia (Arai and Brinckmann-Voss 1980)

Bougainvillia superciliaris
Widely circumboreal in Atlanitc and Pacific (Arai and Brinckmann-Voss 1980)



Bougainvillia muscus has an epibenthic hydroid and a planktonic medusa (Calder 1988).. Hydroids reproduce asexually by stolons, and vary greatly, from monosiphonic and sparsely branched colonies, as small as 1 mm, to complex bushy structures up to 120 mm high (Schuchert 2007). Medusae are budded off from gonophores, and have separate sexes. For a related species, B. nana, male medusae live for an anverage of 15 days, while females live for an average of 30 days (Denitto et al. 2007). Sperm and eggs are released into the water, and fertilized eggs develop into planula larvae, which settle, and develop into hydroids (Barnes 1983).

Bougainvillia muscus ranges from tidepools to depths of 100 m, from cold-temperate to tropical regions, and from oceanic waters to the Black Sea and western Baltic, with polyhaline salinities (Schuchert 2007). The medusae feed on zooplankton.



Trophic Status:




General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatVessel HullNone
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone
Vertical HabitatPlanktonicNone

Tolerances and Life History Parameters

Minimum Salinity (‰)13None
Minimum Height (mm)1Schuchert 2007
Maximum Height (mm)120Schuchert 2007
Broad Temperature RangeNoneCold temperate-Tropical
Broad Salinity RangeNonePolyhaline-Euhaline

General Impacts

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NEA-III None 1862 Native Estab
NEA-II None 0 Native Estab
AUS-VIII None 1971 Def Estab
AUS-X None 1931 Def Estab
NA-ET4 Bermuda 1976 Crypto Estab
WA-IV None 1898 Crypto Estab
WA-V None 1898 Crypto Estab
SA-II None 0 Crypto Estab
SA-III None 0 Crypto Estab
SA-I None 1980 Crypto Estab
NWP-4a None 0 Crypto Estab
MED-III None 0 Native Estab
NEP-III Alaskan panhandle to N. of Puget Sound 1978 Crypto Estab
SP-XXI None 1945 Def Estab
MED-VI None 0 Native Estab
NZ-IV None 1953 Def Estab
MED-II None 0 Native Estab
MED-IV None 0 Native Estab
MED-VII None 0 Native Estab
MED-IX None 0 Native Estab
NWP-3a None 2007 Crypto Estab
CAR-VII Cape Hatteras to Mid-East Florida 0 Crypto Estab
CAR-IV None 0 Crypto Estab
WA-I None 0 Crypto Estab
WA-VI None 0 Crypto Estab
SEP-H None 0 Crypto Estab
NEA-V None 0 Native Estab
MED-I None 0 Native Estab
PAN_PAC Panama Pacific Coast 0 Crypto Estab
NEP-V Northern California to Mid Channel Islands 1972 Crypto Estab
P112 _CDA_P112 (Bodega Bay) 1972 Crypto Estab
AR-V None 0 Native Estab
NEA-IV None 0 Native Estab
NZ-VI None 1996 Def Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 0 Crypto Estab
NA-ET2 Bay of Fundy to Cape Cod 1874 Crypto Estab
NA-ET3 Cape Cod to Cape Hatteras 0 Crypto Estab
SEP-B None 0 Crypto Estab
NWP-3b None 0 Crypto Estab
SEP-I None 2019 Crypto Estab
SEP-Z None 2016 Crypto Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Skora, Michał; Guðni, E.; Guðbergsson; Copp, Gordon H. (2023) Evidence of successful recruitment of non-native pink salmon Oncorhynchus gorbuscha in Iceland, Journal of Fish Biology 104: 329-334
DOI: 10.1111/jfb.15556

Skora, Michał; Guðni, E.; Guðbergsson; Copp, Gordon H. (2023) Evidence of successful recruitment of non-native pink salmon Oncorhynchus gorbuscha in Iceland, Journal of Fish Biology 104: 329-334
DOI: 10.1111/jfb.15556

Arai, M.N., Brinckmann-Voss, A. (1980) Hydromedusae of British Columbia and Puget Sound, Canadian Bulletin of Fisheries and Aquatic Sciences 204: 1-192

Calder, D. R.; Mallinson, J. J.; Collins, K.; Hickman, C. P. (2003) Additions to the hydroids (cnidaria) of the Galapagos, with a list of species reported from the islands, Journal of Natural History 37: 1173-1218

Calder, Dale R. (1988) Shallow water hydroids of Bermuda. The Athecatae.”, Royal Ontario Museum Life Sciences Contributions 148: 1-107

Calder, Dale R. (2010) Some anthoathecate hydroids and limnopolyps (Cnidaria, Hydrozoa) from the Hawaiian archipelago, Zootaxa 2590: 1-91

Calder, Dale R.; Hester, Betty S. (1978) Phylum Cnidaria., In: Zingmark, Richard G.(Eds.) An Annotated Checklist of the Biota of the Coastal Zone of South Carolina. , Columbia. Pp. 87-93

California Academy of Sciences 2005-2015 Invertebrate Zoology Collection Database. <missing URL>

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

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

Farrapeira, Cristiane Maria Rocha; Tenório, Deusinete de Oliveira ; do Amaral, Fernanda Duar (2011) Vessel biofouling as an inadvertent vector of benthic invertebrates occurring in Brazil, Marine Pollution Bulletin 62: 832-839

Fauchauld, Kristian (1977) Polychaetes from Intertidal Areas in Panama, with a Review of Previous Shallow-Water Records, Smithsonian Contributions to Zoology 221: 1-81

Galea, Horia R.; Häussermann, Verena; Försterra, Günter (2007) Cnidaria, Hydrozoa: latitudinal distribution of hydroids along the fjords region of southern Chile, with notes on the world distribution of some species., Check List 3(4): 308-320

Hewitt, C.L.; Campbell, M.L.; Thresher, R.E.; Martin, R.B. (1999) Marine Biological Invasions of Port Phillip Bay, Victoria, In: (Eds.) . , Hobart, Tasmania. Pp. <missing location>

Kazyak (1998) Pocomoke River Basin: Environmental Assessment of Stream Conditions, Maryland Department of Natural Resources, Annapolis. Pp. <missing location>

Lennox, Robert J. ; Berntsen, Henrik H.; Garseth, Åse Helen; Hinch, Scott G.; Hindar, Kjetil; Ugedal, Ola; Utne, Kjell R.; Vollset, Knut Wiik; Whoriskey, Frederick G.; Thorstad. Eva B. (2023) Prospects for the future of pink salmon in three oceans: From the native Pacific to the novel Arctic and Atlantic, Journal of Fish Biology 24: 759–776
DOI: 10.1111/faf.12760

Looby, Audrey; Ginsburg, David W. (2021) Nearshore species biodiversity of a marine protected area off Santa Catalina Island, California, Western North American Naturalist 81(1): 113-130

McGlade, Ciara L. O. ;Dickey, James W. E.; Kennedy, Richard; Donnelly, Shannon; Nelson, Clare‑Ann; Dick. Jaimie T. A.; Gareth, Arnott, (2022) Behavioural traits of rainbow trout and brown trout may help explain their differing invasion success and impacts, Scientific Reports 12: Published online

Megina, Cesar; Gonzalez-Duarte, Manuel M.; Lopez-Gonzalez, Pablo J. Piraino, Stefano (2013) Harbours as marine habitats: hydroid assemblages on sea-walls compared with natural habitats, Marine Biology 160(2): 371-381

Miglietta, Maria Pia; Rossi, Marco; Collin, Rachel (2008) Hydromedusa blooms and upwelling events in the Bay of Panama, Tropical East Pacific., Journal of Plankton Research 30(7): 783-793

Millard, N. A. H. (1959) Hydrozoa from ships' hulls and experimental plates in Cape Town docks., Annals of the South African Museum 45: 239-255

Mills, C.E. (1981) Seasonal occurrence of planktonic medusae and ctenophores in the San Juan archipelago (NE Pacific), Wasmann Journal of Biology 39: 6-29

Mills, Claudia and 16 other authors (2000) The 1998 Puget Sound Expedition: A Shallow Water Rapid Assessment Survey for Nonindigenous Species, with Comparisons to San Francisco Bay., In: Pederson. Judith(Eds.) Marine Bioinvasions. , Cambridge. Pp. 130-138

Mills, Claudia; Marques, Antonio; Migotto, Alvaro E; Calder, Dale R.; Hand, Cadet (2007) The Light and Smith Manual: Intertidal invertebrates from Central California to Oregon (4th edition), University of California Press, Berkeley CA. Pp. 118-168

Philippe, Herve; Brinkmann, Henner; Martinez, Pedro; Riutort, Marta; Baguna, Jaume (2007) Acoel flatworms Are Not Platyhelminthes: Evidence from phylogenomics, PLOS ONE 8(e717): Published online

Philippe, Herve; Brinkmann, Henner; Martinez, Pedro; Riutort, Marta; Baguna, Jaume (2007) Acoel flatworms Are Not Platyhelminthes: Evidence from phylogenomics, PLOS ONE 8(e717): Published online

Schuchert, Peter (2007) The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Filifera Part 2, Revue Suisse de Zoolgie 114(2): 195-396

Short, Frederick T. (Ed.) (1992) The Ecology of the Great Bay Estuary, U. S. Navy, Environmental Protection Agency, Narragansett, RI. Pp. <missing location>

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database.

Watson, J. E. (1999) Review of hydroids introduced to Victorian waters., In: Hewitt, C.; Campbell, M.;Thresher, R. Martin, R.(Eds.) Marine Biological Invasions of Port Phillip Bay, Victoria. , Hobart, Tasmania. Pp. 88-107.

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