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:


Lissoclinum fragile was described from Bermuda in 1902. Is is a colonial tunicate which forms very falt, thin, encrusting colonies. The test of the colony is very fragile,in part due the density of white, calcareous burr-like spicules, ~0.02 mm in idameter, and also the exttensive shared cloacal cavities. The apertures protedt above the surface of the colony. The zooids are aout 1.5 mm long. The branchoial aperture is six-lobed and crown-shamped, while the anal aperture has a languet,. The brancial sac is lange, with four rows of stigmata, and ~10-11 rows. The intestinal loop is small, and the stomach is thin-walled. There are two pear-shaped testes in the intestinal loop, united by common duct. The ovary is represented by a small group of eggs. Colonies can reach up to 60-80 mm, but are 2-3 mm thick, and tear easily. The colonies are usually snowy white due to spiqules, but zooids are orange (Eldredge 1966; Van Name 1945).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Chordata
Subphylum:   Tunicata
Class:   Ascidiacea
Order:   Aplousobranchia
Family:   Didemnidae
Genus:   Lissoclinum
Species:   fragile


Diplosomoides fragile (Van Name, 1902)
Diplosomoides molle (Sluiter, 1909)
Lissoclinum fragile (Van Name, 2921)

Potentially Misidentified Species



Life History- A colonial 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 Didemnidae have small zooids, completely embedded in an encrusting and thin tunic. Each zooid has an oral siphon and an atrial aperture which opens to a shared cloacal chamber. Water is pumped into the oral siphon, through finely meshed ciliated gills on the pharynx, where phytoplankton and detritus is filtered, and passed on mucus strings to the stomach and intestines. Excess waste is 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. Fertilized eggs are brooded within the tunic 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).

Lissoclinum fragile is widely distributed in tropical and subtropical habitats, including stones, pilings, and offshore oil platforms (Van Name 1945; Venugopalan and Wagh, 1990).


Phytoplankton, detritius

Trophic Status:

Suspension Feeder



General HabitatRockyNone
General HabitatMarinas & DocksNone

Life History

Tolerances and Life History Parameters

Maximum Length (mm)80Van Name 1945
Broad Temperature RangeNoneSubtropical-Tropical
Broad Salinity RangeNonePolyhaline-Euhaline

General Impacts

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NA-ET4 Bermuda 1902 Crypto Estab
CAR-IV None 1915 Crypto Estab
CAR-III None 0 Crypto Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 1945 Crypto Estab
NEA-VI None 0 Crypto Estab
CAR-VII Cape Hatteras to Mid-East Florida 0 Crypto Estab
CAR-II None 0 Crypto Estab
SP-XIII None 1955 Def Estab
EAS-III None 1941 Crypto Estab
SP-XII None 1998 Def Estab
CIO-II None 1981 Crypto Estab
CIO-I None 0 Crypto Estab
SA-II None 1969 Crypto Estab
AG-5 None 1994 Crypto Estab
AG-4 None 1994 Crypto Estab
SP-XXI None 1962 Def Estab
SA-III None 0 Crypto Estab
SP-XVI None 1962 Def Estab
EAS-I None 1909 Crypto Estab
EAS-VI None 0 Crypto Estab
SEP-H None 1970 Def Estab
NEP-VII None 2012 Def Estab
NEP-VIII None 2012 Def Estab
SA-I None 2004 Def Estab
PAN_PAC Panama Pacific Coast 2009 Def Estab
WA-I None 1994 Crypto Estab
SP-IV None 0 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Ali, H. Abdul Jaffar; Sivakumar, V.; Tamilselvi, M. (2009) Distribution of alien and cryptogenic ascidians along the southern coasts of Indian peninsula, World Journal of Fish and Marine Sciences 1(4): 305-312

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

Berrill, N. J. (1932) Ascidians of the Bermudas, Biological Bulletin 62(1): 77-88

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

da Rocha, Rosana M.; Bonnet, Nadia Y. K. (2009) [Ascídians (Tunicata, Ascidiacea) introduced to the Alcatraz achipelago, São Paulo], Iheringia Series Zoologie 99: 27-35

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

da Rocha, Rosana M.; Moreno, Tatiane M.; Metri, Rafael (2005) [Ascidians of the Marine Biological Reserve of Avoredro, Santa Catarina, Brazil)., Revista Brasileira de Zoologia 22(2): 461-476

Dias, G. M.; Rocha, R. M.; Lotufo, T. M. C.; Kremer, L. P. (2013) Fifty years of ascidian biodiversity research in Sao Sebastiao, Brazil, Journal of the Marine Biological Association of the United Kingdom 93(1): 273-282

Eldredge, L. G. (1966) Taxonomic review of Indo-Pacific didemnid ascidians and descriptions of twenty-three central Pacific species., Micronesica 2: 161-261

Goodbody, Ivan; Webber, Mona (2003) <missing title>, 3 Environmental Foundation of Jamaica, Kingston. Pp. <missing location>

Monniot, Claude; Monniot, Francoise (1994) Additions to the inventory of Eastern tropical Atlantic Ascidians: arrival of cosmopolitan species., Bulletin of Marine Science 54(1): 71-93

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, Françoise (1983) [littoral ascidians of guadeloupe. i. didemnidae] (french), Bulletin du Museum National d'Histoire Naturelle. 4e Serie. Section A. Zoologie, Biologie et Ecologie Animales 5(1): 5-49

Moreno-Davila, Betzabe Berenice (2010) <missing title>, Universidad del Mar, campus Puerto Angel, Oaxaca, Puerto Angel, Oaxaca, Mexico. Pp. 116

Schwindt, Evangelina and 15 authors (2014) Marine fouling invasions in ports of Patagonia (Argentina) with implications for legislation and monitoring programs, Marine Environmental Research 99: 60-68

Tamilselvi, M. ; Sivakumar, V.; Ali, H. Abdul Jaffar; Thilaga, R. D. (2011) Distribution of alien tunicates (ascidians) in Tuticorin coast, India, World Journal of Zoology 6(2): 164-172

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

Tokioka, Takasi (1972) On a small collection of ascidians from the Pacific coast of Costa Rica, Publications of the Seto Marine Biological Laboratory 19(6): 383-408

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

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

Venugopalan, V. P.; Wagh, A. (1990) Biofouling of an offshore oil platform: Faunal composition and biomass, Indian Journal of Marine Science 19: 53-56