NEMESIS Bioregion Distribution:


Native  Introduced  Cryptogenic  Failed


First Non-native North American Marine/Estuarine Record: 1877
First Non-native West Coast Marine/Estuarine Record: 1915
First Non-native East/Gulf Coast Marine/Estuarine Record: 1877



General Invasion History:

The precise origin of Styela plicata is unknown. The type specimen was described from a ship in the Delaware River, Philadelphia, Pennsylvania in 1823 (Van Name 1912). It was apparently well established south of Cape Hatteras by the late 19th and early 20th centuries before regular collecting began. It is believed to have been introduced to the Mediterranean, probably centuries ago (Monniot, in Food and Agricultural Organization 2000). James T. Carlton considers the species introduced to the Northwest Atlantic, based on the general diversity of this genus in the Pacific (Carlton and Rucklelshaus 1997; Carlton, pers. comm.).  Genetic analysis by de Barros et al. (2009) suggested the Northwest Pacific as the probable native region. However, another study (Pineda et al. 2011) found the highest genetic diversity in the Western Atlantic, although the authors could not definitely identify a native region. The cladistic history of the genus Styela does support a Northwest Pacific ancestry of S. plicata, since it is distinct both from an Eastern Atlantic clade of warm-shallow water Styela, and cold deep-water forms (e.g. S. rustica (Carlton et al., in prep.)). Pineda et al's (2011) genetic analysis is consistent with historical data that suggests that transport of S. plicata began very early, and was very frequent, blurring genetic distinctions among native and introduced populations.

North American Invasion History:

Invasion History on the West Coast:

In the Northeast Pacific, Styela plicata was first collected in San Diego Bay in 1915 and ranges north to Santa Barbara, California (Lambert and Lambert 1998). To the south, it has been reported from Baja California, Mexico, being collected in Ensenada in 2000 (Lambert and Lambert 2003) and Bahia San Quintin in 2005 (Rodriguez and Ibarra-Obando 2008). 

Invasion History on the East Coast:

The type specimen for Styela plicata was described from a ship in the Delaware River, Philadelphia, Pennsylvania in 1823 (Van Name 1912; 1945). However, because this specimen was reported from a vessel hull and not as present in the surrounding environment, we do not consider this record to be its date of introduction.  It was also collected in 1880 on Blackfish Bank, off Charleston, South Carolina (USNM 6960, U.S. National Museum of Natural History 2007). The long-established range of S. plicata along the Western Atlantic is from Cape Lookout, North Carolina (USNM 14790, U.S. National Museum of Natural History 2007) to Padre Island, Texas (USNM 14424, U.S. National Museum of Natural History 2007), and south through the Caribbean to Venezuela (Van Name 1945; USNM 14481, U.S. National Museum of Natural History 2007). Recently, however, S. plicata has been collected north of Cape Hatteras, in Lynnhaven Bay, Virginia Beach, at the mouth of Chesapeake Bay (Ruiz et al., unpublished data), in Chincoteague Bay, Virginia (in 1999, O'Beirn et al. 2004, on oyster-culture floats), and in the Mystic River, Long Island Sound (one specimen in 2001, but not yet established in Long Island Sound as of 2011; J.T. Carlton personal communication).

Invasion History on the Gulf Coast:

A specimen of Styela plicata was collected from Padre Island, Texas (USNM 14424, U.S. National Museum of Natural History 2007) and Cedar Key, Florida in 1877 (USNM 940, U.S. National Museum of Natural History 2007). This tunicate is established and abundant on the Gulf Coast from Florida through Texas (Van Name 1921; Van Name 1945; Ruiz et al., unpublished data).

Invasion History elsewhere in the World:

The long-established range of Styela plicata along the Western Atlantic is from Cape Lookout, North Carolina (USNM 14790, U.S. National Museum of Natural History 2007) to Padre Island, Texas (USNM 14424, U.S. National Museum of Natural History 2007), and south through the Caribbean to Venezuela (Van Name 1945; USNM 14481, U.S. National Museum of Natural History 2007). In 1884, S. plicata was reported from St. Thomas, US Virgin Islands/Caribbean Sea (USNM 6916, U.S. National Museum of Natural History 2007), and from Bermuda in 1882 (USNM 2769, U.S. National Museum of Natural History 2007) suggesting that it was established and widespread in warm waters of the Western Atlantic by the late 19th century.

Styela plicata was collected from Panama in 1973 (USNM 19744, US National Museum of Natural History 2007). Nearly a century before, in 1883, it was collected from Rio de Janeiro state, Brazil (Trautstedt 1883, cited by da Rocha and Kremer 2005), It ranges south to Uruguay (Orensanz et al. 2002), but in Bahia, northern Brazil, it was known only from 'one individual' (da Rocha and Kremer 2005).

Styela plicata is considered introduced to the Mediterranean: ['This species is not native to the Mediterranean, but was introduced centuries ago. It is present in all warm-temperate and tropical regions, especially in zones of human activity.'] (C. F. Monniot, in Food and Agricultural Organization 2000). It was collected from Naples (Traustedt 1877, cited by Kott 1985) and Trieste, Italy (Heller 1877, cited by Kott 1998). Outside the Mediterranean, it has been collected from Dakar, Senegal (Monniot 1969).

In the Northwest Pacific, S. plicata ranges from Hong Kong (Huang 2001) to Mutsu Bay, at the north end of Honshu, Japan (Oka 1935, cited by Nishikawa 1991). Within the Indian Ocean, it has been collected from Vizhinjam, India, on the Arabian Sea (Abdul and Sivakumar 2007), Somalia (in 1964, USNM 18297, U.S. National Museum of Natural History 2007), and the Gulf of Suez (in 1927, Monniot 2002). These scattered records could represent introductions.

In the Southwest Pacific, S. plicata was first collected at Port Jackson, near Sydney, Australia (Heller 1878, cited by Kott 1985). Its range runs from the mouth of the Calliope River, Queensland to Port Phillip Bay (in 1963, Millar 1966, cited by Keough and Ross 1999), and west to Cockburn Sound and the Perth area (Hartmeyer and Michaelsen 1928, cited by Kott 1985). Within this range, it is strongly associated with harbors and artificial structures (Kott 1985; Keough and Ross 1999). A genetic survey indicates high diversity in Australian populations, with significant genetic structure in more southern latitudes, but no structure in tropical latitudes (David et al. 2010). In New Zealand, it has been reported at several locations on the North Island, including Auckland Harbour and Hauraki Gulf (in 1957, Cranfield et al. 1998), Gulf Harbour Marina (Inglis et al. 2005), and Taranaki (Inglis et al. 2006).