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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: Asian tunicate

Synonyms and Other Names: club tunicate, sea squirt.

Taxonomy: available through www.itis.gov

Identification: Solitary; club-shaped; yellowish-gray to reddish-brown.  Thick tunic, leathery with conspicuous bumps.  Siphons near top; both siphons pointed upward (Meinkoth 1981).

Size: 15 cm high, 51 mm wide (Meinkoth 1981).

Native Range: Asia (Meinkoth 1981).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Means of Introduction: Ballast water release and/or ship fouling (Meinkoth 1981).  It is believed to have come from Japan via Europe sometime in the late 1960s (Berman et al. 1992).  Carried on ship hulls into harbors in California, Europe, and Australia at the beginning of the century (Meinkoth 1981).
 

Status: Established. One of the two dominant tunicates in Newport Harbor by 1949. This species still dominates (Lambert and Lambert 1995).  This species was rare in Beverly, Massachusetts, in the spring of 1970.  By the late 1970s it had become common, and it is now abundant (Berman et al. 1992).  First found in New Hampshire in Portsmouth Harbor in 1985.  As of Novermber 1990, it had not been found at Newcastle,  New Hampshire  (Berman et al. 1992).  Therefore, it is not increasing as rapidly as the population in Massachusetts (Berman et al. 1992).

Impact of Introduction: A dominant competitor.  Has apparently replace the native solitary tunicates Pyura haustor and Ascidia ceratodes in California (Lambert and Lambert 1995).  Now occurs  in monoculture stands on floating and fixed sublittoral substrates in many parts of southern New England, occurring by the tens of thousands in regions previously occupied by the blue mussel, Mytilus edulis (Carlton 1989).    Berman et al. (1992) predict that if it becomes abundant in the northern part of its range, S. clava will competitively exclude Mytilis edulis and Metridium senile.

Remarks: Used as seafood in Korea (Meinkoth 1981). 

References: (click for full references)

Berman, J., L. Harris, W. Lambert, M. Buttrick, M. Dufresne.  Recent invasions of the Gulf of Maine: three contrasting ecological histories.  Conservation Biology 6(3):435-441.

Carlton, J.T.  1989.  Man's role in changing tohe face of the ocean: biological invasions and implications for conservation of near-shore environments.  Conservation Biology 3(3):265-273.
 

Lambert, G., and C.C. Lambert. 1995. Nonindigenous sea squirts in California Harbors. Aquatic Nuisance Species Digest 1(2):17,20.

Meinkoth, N.A.  1981.  The Audubon Society Field Gude to North American Seashore Creatures.  Alfred A. Knopf., New York, NY.  813 pp.

Ruiz, G. M., P. W. Fofonoff, J. T. Carlton, M. J. Wonham, and A. H. Hines. 2000. Invasion of coastal marine communities in North America: Apparent patterns, processes, and biases. Annual Review of Ecological Systematics. 31: 481-531.

Author: Fuller, P.

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.