Invasion History

First Non-native North American Tidal Record: 1972
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record: 1972

General Invasion History:


North American Invasion History:


The shell of Amphibalanus sublabidus is usually conical or subcylindrical. The orifice is slightly toothed, and its width is usually more than 1/2 its height. The plates have a smooth surface, with narrow longitudinal spaces (radii), narrowing to the tops of shell plates. The radii vary in width, narrower in subcyliindric specimens, and wider in more conical specimens. The tergum has a blunt apex, and its spur is broad and blunt, with the length about 9/10 of the width (Henry and McLaughlin 1975). Amphibalanus improvisus grows up to 20 mm in diameter. The outer parietal plates are dirty white (sometimes with narrow lavender stripes) with inner plates (ale), white. This barnacle is characteristic of low brackish estuarine habitats, with very low or highly variable salinity (Henry and McLaughlin 1975; Kennedy 1983). Larval stages of A.subalbidus are illustrated by Lang (1979; 1980).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Arthropoda
Subphylum:   Crustacea
Class:   Maxillopoda
Subclass:   Thecostraca
Infraclass:   Cirripedia
Superorder:   Thoracica
Order:   Sessilia
Suborder:   Balanomorpha
Superfamily:   Balanoidea
Family:   Balanidae
Genus:   Amphibalanus
Species:   subalbidus


Balanus amphitrite pallidus (Henry, 1954)
Balanus canabus (Zullo and Buising, 1989)

Potentially Misidentified Species

Balanus amphitrite

Balanus pallidus



Like many other barnacles, Amphibalanus subalbidus, is hermaphroditic, but is capable of cross-fertilization. The fertilized eggs are brooded in the mantle cavity, sometimes for several months, and are released as nauplius larvae with three pairs of appendages (Barnes 1983). The nauplii feed in the plankton and go through five successive molts, column before molting into a non-feeding cypris stage, covered with a pair of chitinous shells (Lang and Marcy 1982; Furman and Yule 1991). Cyprids swim, investigating suitable surfaces, and then settle, secreting a shell, and molting into the first juvenile barnacle stages. Juvenile and adult barnacles are filter feeders, sweeping the water with their long bristled appendages to gather phytoplankton, zooplankton, and detritus (Barnes 1983).

The Bay Barnacle, Amphibalanus isubalbidus, is characteristic of low-salinity estuaries and brackish waters,but it has been collected at 23 PSU ((McPherson et al. 1985).). In estuaries, it has been found at 0.8 PSU, but may require salinities of above 2 PSU for reproduction (Dineen and Hines 1992). It is typically found in lower intertidal and subtidal zones, in sheltered waters. This barnacle grows on a wide range of hard surfaces, including logs, rocks, , oysters, mangroves buoys and ship hulls (Kennedy and de Cosimo 1980; Farrapeireira 2010).


General HabitatCoarse Woody DebrisNone
General HabitatOyster ReefNone
General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatMangrovesNone
General HabitatVessel HullNone
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Tidal RangeSubtidalNone
Tidal RangeLow IntertidalNone
Vertical HabitatEpibenthicNone

Tolerances and Life History Parameters

Minimum Salinity (‰)0.8Field survey, Chesapeake Bay, Kennedy and DiCosimo (1983).
Maximum Salinity (‰)23Field survey, Indian River Lagoon FL (McPherson et al. 1985).
Minimum Reproductive Salinity2Successful settlement (Dineen et al. 1994)
Maximum Width (mm)20Henry and McLaughlin 1975
Broad Temperature RangeNoneWarm-Temperate-Subtropical-Tropical
Broad Salinity RangeNoneOligohaline to Polyhaine

General Impacts

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 1923 Native Estab
CAR-III None 0 Native Estab
CAR-VII Cape Hatteras to Mid-East Florida 0 Native Estab
NA-ET3 Cape Cod to Cape Hatteras 0 Native Estab
NA-ET2 Bay of Fundy to Cape Cod 1972 Def Unk
NEP-VII None 1989 Def Estab
SA-III None 1994 Def Estab
M060 Hudson River/Raritan Bay 1972 Crypto Estab
N170 Massachusetts Bay 1972 Def Unk
AG-2 None 2011 Def Estab
M040 Long Island Sound 2017 Def Unk

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Carlton, James T.; Newman, William A.; Pitombo, Fábio Bettini (2011) In the wrong place- Alien marine crustaceans: Distribution, biology, impacts, Springer, Dordrecht. Pp. 159-213

Celis, Antonio; Rodríguez-Almaráz, Gabino; Álvarez, Fernando (2007) [The shallow-water thoracican barnacles (Crustacea) of Tamaulipas, Mexico], Revista Mexicana de Biodiversidad 78: 325-337

Dineen, Joseph F.; Hines, Anson H. (1994) Larval settlement of the polyhaline barnacle Balanus eburneus: cue interactions and comparisons with two estuarine congeners., Journal of Experimental Marine Biology and Ecology 179: 223-234

Farrapeira, Christiane M. R. (2010) Barnacles (Crustacea:Cirripedia) of the estuarine and marine areas of the port of Recife (Pernambuco, Brazil), Cahiers de Biologie Marine 50: 199-129

Furman, E. R.; Yule, A. B. (1991) Estuaries and coasts: Spatial and temporal intercomparisons., Olsen and Olsen, Fredensborg, Denmark. Pp. Pp. 273-276.

Henry, Dora P.; McLaughlin, Patsy A. (1975) The barnacles of the Balanus amphitrite complex (Cirripedia, Thoracica)., Zoologische Verhandelingen 141: 1-203

Kennedy, Victor S.; DiCosimo, Jane (1983) Subtidal distribution of barnacles (Cirripedia: Balanidae) in Chesapeake Bay, MD., Estuaries 6(2): 95-101

Lang, William H. (1979) Larval development of shallow water barnacles of the Carolinas (Cirripedia: Thoracica) with keys to naupliar stages., NOAA Technical Report NMFS Circular 421: 1-39

Lang, William H.; Marcy, Martha (1982) Some effects of early starvation on survival and development of barnacle nauplii Balanus improvisus, Journal of Experimental Marine Biology and Ecology 60: 63-70

Pederson, Judith, and 13 authors (2021) 2019 Rapid Assessment Survey of marine bioinvasions of southern New England and New York, USA, with an overview of new records and range expansions, Bioinvasions Records 10(2): 22-–237

Pitombo, F. B. (2004) Phylogenetic analysis of the Balanidae (Cirripedia, Balanomorpha)., Zoologica Scripta 33(3): 261-276

Ristich, S. S., Crandall, M., Fortier, J. (1977) Benthic and epibenthic macroinvertebrates of the Hudson River I. Distribution, natural history, and community structure, Estuarine and Coastal Marine Science 5: 255-266

Rodríguez-Almaraz, Gabino A.; García-Madrigal, María del Socorro (2014) [Aquatic Invasive Species in Mexico], Comisión Nacional para el Conocimiento y Uso de la Biodiversidad, <missing place>. Pp. 337-371

Shahdadi, Adnan; Sari, Alireza; Naderloo, Reza (2014) A checklist of the barnacles (Crustacea: Cirripedia: Thoracica) of the Persian Gulf and Gulf of Oman with nine new records, Zootaxa 3784: 201-223

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

Van Syoc, Robert J. (1992) Living and fossil populations of a western Atlantic barnacle, Balanus subalbidus Henry, 1974, in the Gulf of California region, Proceedings of the San Diego Society of Natural History 12: 1-7

Yale Peabody Museum of Natural History 2008-2016 YPM Invertebrate Zoology - Online Catalog. <missing URL>

Yasser, Amaal Gh.; Naser, Murtada D.; Ghazi, Abdulhussein H.; Mahdi, Rusul; Younis, Mohammed; Shahen, Mohammed; Ali, Russall (2022) An expansion of the invasive species Amphibalanus subalbidus (Henry, 1973) in the south of Iraq, BioInvasions Records <missing volume>: In press

Young, Paulo S. (1994) Superfamily Balanoidea Leach (Cirripedia, Balanomorpha) from the Brazilian coast., Boletim do Museo Nacional (Zoologia) 356: 1-36