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Club tunicate  Club tunicate  Club tunicate  Club tunicate 

  Scientific Name:

Styela clava

 Common Name:

Club tunicate (also: clubbed tunicate, leathery sea squirt, Asian sea squirt)

 Native Range:


 Established Range:

S. clava has established itself off the coasts of Australia, New Zealand, Europe, and North America. On the East Coast, it is found from Canada to Maryland.

 Established in Rhode Island?

Yes, throughout Narragansett Bay

 Date and Location of Introduction:

1970, Beverly, Massachusetts

 Method of Introduction:

Unknown, but likely ballast water or hull fouling


S. clava generally lives in the subtidal zone, attached to rocks, pilings, floating docks, and the hulls of ships. It can tolerate water temperatures from -2 to 23° Celcius, and salinities between 22 and 36 ppt.

 Average Life Span:

1 to 3 years


S. clava is a filter feeder that eats zooplankton, phytoplankton and detritus.


S. clavais hermaphroditic and breeds by broadcast spawning. In New England, it breeds between June and November.


All invasive tunicates, including S. clava, pose the same problems. These tunicates are notorious fouling organisms, and can completely cover submerged boat hulls, aquaculture cages, and just about any other surface that they are capable of living on. As a result, they can slow down boats and have negative impacts on the local environment. Invasive tunicates have been known to smother shellfish and other sessile organisms, and will outcompete native filter feeders for food and space.


S. clavacan be removed from an infested object by scraping it off by hand and placing it in the garbage or letting it dry out. If you choose to pressure wash it off of equipment, only do so on land and make sure the resulting wastewater does not go back into the sea. Additionally, S. clavacan be removed from smaller objects, such as shellfish, by placing it in vinegar or a brine bath and then exposing it to air.

 Identification Card:

Courtesy of Salem Sound Coastwatch


 Works Cited:

Cohen, Andrew N. 2005. Guide to the Exotic Species of San Francisco Bay. San Francisco Estuary Institute, Oakland, CA,

Fuller, Pam. 2010.   Styela  clava. USGS Nonindigenous Aquatic Species Database, Gainesville, FL.

Clarke, C.L., and T.W. Therriault. Biological Synopsis of the Invasive Tunicate Styela clava(Herdman 1881). Fisheries and Oceans Canada, Nanaimo, BC.