Invasion History

First Non-native North American Tidal Record: 2000
First Non-native West Coast Tidal Record: 2000
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Polyclinum constellatum was described from Mauritius in 1816. It is widely reported from mangroves, dead corals, rocks, and from man-made structures, such as pilings, floats, buoys, etc. (da Rocha et al. 2010; Carlton and Eldredge 2009). Although its discovery in Mauritius suggests an Indian Ocean origin, native status in the tropical Atlantic cannot be excluded. By the end of the 19th century, it was reported from the Gulf of Mexico (in 1887, Florida), the Caribbean Sea (in 1883, Jamaica), Hawaii (in 1873), and Japan (in 1900) (US National Museum of Natural History 2002; Carlton and Eldredge 2009). We consider it cryptogenic in the western Atlantic, Indian Ocean, and the western Pacific. Polyclinum constellatum is considered introduced in Guam (Lambert 2002; Lambert 2003), Tahiti (Monniot and Monniot 1985), and the Hawaiian Islands (Carlton and Eldredge 2009). It was found at the western entrance to the Panama Canal in 2002-2009 (Ruiz et al., unpublished data; Carman et al. 2010) where Carman et al (2010) considered it cryptogenic. In 2008-2009, it was found in Pacific Mexico, near Mazatlan, at the mouth of the Gulf of California (Tovar-Hernandez et al. 2010). One specimen was identfied on fouling plates in San Diego Bay in 2000 (Ruiz et al., unpublished data).

North American Invasion History:

Invasion History on the West Coast:

In the summer of 2000, a single specimen of Polyclinum constellatum was identified on settlement plates from Navy Pier 14 in San Diego (Ruiz et al., unpublished data). The population status of this species in southern California is not known. In 2008-2009, it was discovered further south, in the Urias estuary, near the port of Mazatlan, Mexico, and in a nearby oyster farm (Tovar-Hernández et al. 2010).

Invasion History on the East Coast:

Van Name (1921; 1945) mentions the occurrence of Polyclinum constellatum on the west coast of Florida, but not on the east coast. However, Weiss (1948) found it on fouling plates in Biscayne Bay in 1944-1946. It was found in Bermuda before 1972 (Monniot 1972). Currently, it is known from waters off Georgia (in 1981, USNM 24319), the Indian River Lagoon (Mook 1983, Ruiz et al. unpublished), and Biscayne Bay (Weiss 1948; Ruiz et al., unpublished data).

Invasion History on the Gulf Coast:

The first collection of Polyclinum constellatum in US waters was in Cedar Key, Florida, in the Gulf of Mexico in 1887 (USNM 6975, US National Museum of Natural History 2010). It was collected in the Dry Tortugas in the 1880s ( USNM 7137, US National Museum of Natural History 2010, exact date unknown); Cedar Key, Florida in 1887; Tampa Bay (Gretchen Lambert 2003, personal communication); and South Padre Island, Texas in 2004 (Lambert et al. 2005). As noted above, we consider this tunicate cryptogenic in the western Atlantic.

Invasion History in Hawaii:

The first Hawaiian record for Polyclinum constellatum is from Oahu in 1873 (Carlton and Eldredge 2009). Subsequently it was reported from Pearl Harbor in 1920 (Coles et al. 1999b, Carlton and Eldredge 2009); Honolulu Harbor in 1997 (Coles et al. 1999a); Ala Wai Harbor in 1998 (Coles et al. 1999a); Kaneohe Bay in 1999 (Coles et al. 2002); and Waikiki in 2001 (Coles et al. 2002). In Hawaii, this tunicate occurs on floats and pilings, but also on dead coral, and under rocks at exposed locations (Carlton and Eldredge 2009).

Invasion History Elsewhere in the World:

Polyclinum constellatum was described from Mauritius in 1816. Although its discovery in Mauritius suggests an Indian Ocean origin, native status in the tropical Atlantic cannot be excluded. Because of this uncertainty, it is considered to be cryptogenic throughout much of its global range. It was reported from Jamaica in 1883 and Japan in 1900 (US National Museum of Natural History 2002; Carlton and Eldredge 2009). Polyclinum constellatum is widely distributed throughout the Caribbean (Van Name 1945) and has also been reported from Tahiti (Monniot and Monniot 1985), New Caledonia (Monniot 1987), Tanzania (Monniot and Monniot 1997) and Brazil (da Rocha and Costa 2005). During 2009, P. constellatum was found on the Atlantic and Pacific sides of the Panama Canal (Carman et al. 2011), where Carman et al (2011) considered it to be cryptogenic.

In 1998, Polyclinum constellatum was collected on man-made substrates in Apra Harbor, Guam (USNM 25073, US National Museum of Natural History 2010; Lambert 2002; Lambert 2003) and we consider it introduced here. In 2016, it was collected from docks in two harbors on Santa Cruz Island in the Galapagos, its first record there (Lambert 2019).


Polyclinum constellatum is a colonial encrusting tunicate. It can be grey, purplish brown or green in color, with white or beige systems of zooids visible on the surface. The attachment area of the colony can be small, so that only a small part of the base is directly attached to the substratum (Van Name, 1945). Colonies are firm and cartilaginous, often without attached debris, but sometimes colonized by hydroids or other epifauna (da Rocha and Costa 2005). Colonies range in size from 25-65 mm long and 5-20 mm thick. The zooids of P. constellatum are about 5-7 mm long when straightened. Zooids are arranged in circular systems, of about 20 zooids each, which border a circular common cloaca (or atrial siphon). The oral siphons are tubular and fringed by six long and triangular lobes (da Rocha and Costa 2005). The reproductive organs are located in the post-abdomen, with the testes forward to the ovaries (Van Name 1945; da Rocha and Costa 2005).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Chordata
Subphylum:   Tunicata
Class:   Ascidiacea
Order:   Aplousobranchia
Family:   Polyclinidae
Genus:   Polyclinum
Species:   constellatum


Polyclinum festum (Hartmeyer, 1905)
Polyclinum brasiliense (Michaelsen, 1923)

Potentially Misidentified Species



A colonial (or compound) tunicate consists of many zooids, bearing most or all of the organs of a solitary tunicate, but modified to varying degrees for colonial life. Colonial tunicates of the family Polyclinidae have zooids organized around cloacal systems. Each zooid has a thorax, an abdomen and a posterior abdomen. The thorax has an oral siphon and an atrial aperature with an anterior lip, which open to the surface. Below the thorax, the abdomen contains the stomach and intestines, while the posterior abdomen contains the ovaries, testis, and heart. Water is pumped into the oral siphon, through finely meshed ciliated gills along the pharynx, where it is filtered, and passed on mucus strings to the stomach and intestines. Excess waste is then expelled in the outgoing atrial water (Van Name 1945; Barnes 1983).

Colonial tunicates reproduce both asexually by budding and sexually from fertilized eggs that develop into larvae. Buds can form from the body wall of the zooids. Colonies vary in size ranging from small clusters of zooids to huge spreading masses. The zooids are hermaphroditic, which means both eggs and sperm are released into the atrial chamber. Eggs may be self-fertilized or fertilized by sperm from nearby animals, but some species have a partial block to self-fertilization. Eggs are brooded in the atrial chamber until they hatch into lecithotrophic (non-feeding, yolk-dependent) tadpole larvae. The larva has a muscular tail and a notochord, eyespots, and a set of adhesive papillae. The larvae are expelled upon hatching and swim briefly before settlement. Swimming periods are usually less than a day, but some larvae settle immediately after release or swim for longer periods if the water temperature is low. On settlement the tail is absorbed, the gill basket expands, and the tunicate begins to feed by filtering (Van Name 1945; Barnes 1983).


Algae, detritus



Trophic Status:

Suspension Feeder



General HabitatMarinas & DocksNone
General HabitatMangrovesNone
General HabitatCoral reefNone
General HabitatRockyNone
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone

Life History

Tolerances and Life History Parameters

Minimum Temperature (ºC)17Field, near southern range limit, Santa Catarina, Brazil (da Rocha et al. 2009)
Maximum Temperature (ºC)29Field, near southern range limit, Santa Catarina, Brazil (da Rocha et al. 2009)
Minimum Salinity (‰)24Field, Ilha Grande Bay, Brazil (Marins et al. 2010)
Maximum Salinity (‰)40Gulf of California, Mazatlan, Mexico (Tovar-Hernandez et al. 2010)
Broad Temperature RangeNoneWarm temperate-Tropical
Broad Salinity RangeNonePolyhaline-Euhaline

General Impacts

Economic Impacts – Polyclinum constellatum has been reported as fouling on cultured mussels (Perna perna) in Hong Kong (da Rocha et al. 2009).

Regional Impacts

SA-IINoneEconomic ImpactFisheries
Polyclinum constellatum was found fouling mussels (Perna perna) in an aquaculture operation in Santa Catarina, Brazil (da Rocha et al. 2009).
NWP-2NoneEconomic ImpactFisheries
Fouling cultured shellfish in Hong Kong (Huang 2003, cited by da Rocha et al. 2009).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
CAR-III None 1884 Crypto Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 1887 Crypto Estab
G080 Suwannee River 1887 Crypto Estab
S206 _CDA_S206 (Vero Beach) 1890 Crypto Estab
CAR-II None 1884 Crypto Estab
CAR-V None 1903 Crypto Estab
SA-II None 1923 Crypto Estab
CAR-IV None 1921 Crypto Estab
SP-XIII None 1955 Crypto Estab
SP-XI None 0 Def Estab
NWP-3b None 1900 Crypto Estab
EAS-III None 1979 Crypto Estab
SA-IV None 1972 Crypto Estab
CAR-VII Cape Hatteras to Mid-East Florida 1981 Crypto Unk
SP-XII None 1998 Def Estab
EA-V None 1816 Crypto Estab
CIO-I None 0 Crypto Estab
SP-XXI None 1873 Def Estab
SA-III None 2002 Crypto Estab
NWP-2 None 2003 Crypto Estab
S190 Indian River 1976 Crypto Estab
S200 Biscayne Bay 1944 Crypto Estab
G330 Lower Laguna Madre 2004 Crypto Estab
SP-XVI None 1985 Def Estab
WA-V None 1955 Crypto Estab
AG-3 None 1994 Crypto Estab
EA-III None 0 Crypto Estab
G070 Tampa Bay 2003 Crypto Estab
SEP-H None 2008 Crypto Estab
NEP-VIII None 2008 Def Estab
NEP-VII None 2009 Def Estab
NEP-VI Pt. Conception to Southern Baja California 2000 Def Unk
P020 San Diego Bay 2000 Def Unk
NA-ET4 Bermuda 0 Crypto Estab
PAN_PAC Panama Pacific Coast 2008 Crypto Estab
PAN_CAR Panama Caribbean Coast 1884 Crypto Estab
EA-IV None 0 Crypto Estab
WA-IV None 2010 Crypto Estab
MED-VI None 2016 Def Estab
NEA-V None 2016 Def Estab
MED-V None 2016 Def Estab
SEP-Z None 2016 Def Estab
MED-IV None 2018 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Abdul, Jaffar Ali H.; Sivakumar, V. (2007) Occurrence and distribution of ascidians in Vizhinjam Bay (south west coast of India)., Journal of Experimental Marine Biology and Ecology 342: 189-190

Bastida-Zavala, Rolando; de León-González, Jesús Ángel; Carballo Cenizo, José Luis; Moreno-Dávila, Betzabé (2014) [Aquatic Invasive Species in Mexico], Comisión Nacional para el Conocimiento y Uso de la Biodiversidad, <missing place>. Pp. 317-336

Caraballo-Pérez, Virginia; Díaz, Oscar (2011) [Tunicates (Tunicata: Ascidiacea) of the Gulf of Cariaco, Venezuela], Boletino del Instituto Oceanographico de Venezuela 50(2): 233-244

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

Carman, Mary R. and 7 authors 2010 Ascidians at the Pacific and Atlantic entrances to the Panama Canal. <missing URL>

Carman, Mary, and 8 authors (2011) Ascidians at the Pacific and Atlantic entrances to the Panama Canal, Aquatic Invasions 6(4): 371-380

Çinar, Melih Ertan and 7 authors (2021) Current status (as of end of 2020) of marine alien species in Turkey, PLOS ONE 16: Published online

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. (2002b) Nonindigenous marine species at Waikîkî and Hawai`i kai, Oahu, Hawai`i, Bishop Museum Technical Report 25: 1-255

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

da Rocha, Rosa Morales and 13 authors (2010) Inventory of ascidians (Tunicata, Ascidiacea) from the National Park La Restinga, Isla Margarita, Venezuela, Biota Neotropica 10: published online

da Rocha, Rosana M.; Costa, Luciana (2005) Ascidians (Urochordata: Ascidiacea) from Arriaal do Cabo, Rio de Janeiro, Brazil., Iheringia Series Zoologie 95(1): 57-64

da Rocha, Rosana M.; Kremer, Laura P.; Baptista, Mariah S.; Metri, Rafael (2009) Bivalve cultures provide habitat for exotic tunicates in southern Brazil., Aquatic Invasions 4(1): 195-205

da Rocha, Rosana M.; Kremer, Laura P. (2005) Introduced ascidians in Paranagua Bay, Parana, southern Brazil., Revista Brasileira da Zoologia 22(4): 1170-1184

Darrigran, Gustavo and 29 authora (2023) Species movements within biogeographic regions: exploring the distribution of transplanted mollusc species in South America, Biological Invasions 25: 673-691

DeFelice, Ralph C.; Coles, Steve L.; Muir, David, Eldredge, L. G. (1998) <missing title>, Hawaii Biological Survey, Bishop Museum, <missing place>. Pp. 1-30

Fisheries and Oceans Canada 2018b Haplosporidium costale (SSO) of Oysters.

Glenner, Henrik; Lützen, Jørgen; , Pacheco-Riaño, Laura Camila; Noever, Christoph (2021) Expansion of the barnacle Austrominius modestus (Darwin, 1854) (Cirripedia, Thoracica, Balanidae) into Scandinavian waters based on collection data and niche distribution modeling, Aquatic Invasions 16: 675-689: <missing location>

Granthom-Costa, Luciana Vieira; Werner Ferreira, Carlos Gustavo; Dias, Gustavo Muniz (2016) Biodiversity of ascidians in a heterogeneous bay from southeastern Brazil, Management of Biological Invasions 7: 5-12

Huang, Xuguang, Bingyu;; Guo, Donghu; Zhong;, Yanping; Li, Shunxing; Liu, Xin;; Laws, Edward A.; Huang, Bangqin (2021) Blackfordia virginica blooms shift the trophic structure to smaller size plankton in subtropical shallow waters, Marine Pollution Bulletin 182(111990): Published online

Lambert, Gretchen (2002) Nonindigenous ascidians in tropical waters., Pacific Science 56(3): 191-298

Lambert, Gretchen (2003) Marine biodiversity of Guam: the Ascidiacea., Micronesica 35-36: 584-593

Lambert, Gretchen (2019) Fouling ascidians (Chordata: Ascidiacea) of the Galápagos: Santa Cruz and Baltra Islands, Aquatic Invasions 14: 132-149

Lambert, Gretchen; Faulkes, Zen; Lambert, Charles C.; Scofield, Virginia L. (2005) Ascidians of South Padre Island, Texas, with a key to species., Texas Journal of Science 57(3): 251-262

Low-Pfeng, Antonio; Recagno, Edward M. Peters (2012) <missing title>, Geomare, A. C., INESEMARNAT, Mexico. Pp. 236

Marins, Flavia O.; Novaes, Roberto L. M.; Rocha, Rosana M.; Junquiera, Andrea O. R. (2010) Non indigenous ascidians in port and natural environments in a tropical Brazilian bay, Zoologia 27(2): 213-222

Monniot, C.; Monniot, F. (1985) [Littoral ascidians of Guadeloupe Island: IX. Characteristics of populations, ecology, relationships with the world fauna] (French), Tethys 11(3-4): 203-213

Monniot, C.; Monniot, F. (1997) Records of ascidians from Bahrain, Arabian Gulf with three new species., Journal of Natural History 31: 1623-1643

Monniot, Claude (1972) [Stolidobranch Ascidians of Bermuda[ (French), Bulletin du Museum National d'Histoire Naturelle. 4e Serie. Section A. Zoologie, Biologie et Ecologie Animales 43: 617-643

Monniot, Claude; Monniot, Francoise (1987) [The Ascidians of French Polynesia] (French), Memoires da Museum d'Histoire Naturelle 136: 106-119

Monniot, Claude; Monniot, Francoise; Griffiths, Charles; Schleyer, Michael (2001) South African Ascidians., Annals of the South African Museum 108(1): 1-141

Monniot, Claude; Monniot, Francoise; Laboutte, Pierre (1985) [Ascidians of the port of Papeete (French Polynesia); Relation to the environment and to intercontinental transport by navigation] (French), Bulletin du Museum National d'Histoire Naturelle. 4e Serie. Section A. Zoologie, Biologie et Ecologie Animales 7(3): 481-495

Monniot, Francoise; Monniot, Claude (1997) Ascidians collected in Tanzania, Journal of East African Natural History 86: 1-35

Montesanto, F.; Chimient, G.; Gissi, C,; Mastrototaro, F, (2022) Polyclinum constellatum (Tunicata, Ascidiacea), an emerging non-indigenous species of the Mediterranean Sea: integrated taxonomy and the importance of reliable DNA barcode data, Mediterranean Marine Science 23(1): 69-83

Mook, David (1983) Indian River fouling organisms, a review, Florida Scientist 26(3/4): 162-167

Quintanilla, Elena; Thomas Wilke; Ramırez-Portilla, Catalina; Sarmiento, Adriana; Sanchez, Juan A. () , None <missing volume>: <missing location>

Quintanilla, Elena; Thomas Wilke; Ramırez-Portilla, Catalina; Sarmiento, Adriana; Sanchez, Juan A.2017 (2017) Taking a detour: invasion of an octocoral into the Tropical Eastern Pacific, Biological Invasions <missing volume>(17): 2583–2597
DOI 10.1007/s10530-017-1469-2

Stewart, Joan G. (1991) Seaweeds and seagrasses of San Diego County, California Sea Grant College, <missing place>. Pp. <missing location>

Tokioka, Takasi (1967) Pacific Tunicata of the United States National Museum, United States National Museum Bulletin 251: 1-247

Tovar-Hernández, M. A.; Villalobos-Guerrero, T. F.; Yáñez-Rivera, B., Aguilar-Camacho, J. M.; Ramírez-Santana, I. D. (2012) [Guide to exotic aquatic invertebrates in Sinaloa] , Geomare, A. C., USFWS, INE-SEMARNAT, Mazatlán, México. Pp. 41

Tovar-Hernández,María Ana; Suárez-Morales, Eduardo; Yáñez-Rivera, Beatriz (2010) The parasitic copepod Haplostomides hawaiiensis (Cyclopoida) from the invasive ascidian Polyclinum constellatum in the southern Gulf of California, Bullerin of Marine Science 86(3): 637-648

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

Van Name, Willard G. (1921) Ascidians of the West Indian region and southeastern United States., Bulletin of the American Museum of Natural History 44: 283-494

Van Name, Willard G. (1945) The North and South American ascidians, Bulletin of the American Museum of Natural History 84: 1-462

Weiss, Charles M. (1948) The seasonal occurrence of sedentary marine organisms in Biscayne Bay, Florida., Ecology 29(2): 153-172