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You are here: Home / Aquatic Species / Species Profiles / Clubbed Tunicate
Aquatic Species
Species Profiles

Clubbed Tunicate

Asian tunicate

Scientific name: Styela clava Herdman, 1881 (ITIS)

Common names: Clubbed tunicate, stalked sea squirt, solitary sea squirt, leathery sea squirt, Pacific rough sea squirt, Asian sea squirt

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Selected Resources

Native To: Eastern Asia (Clarke and Therriault 2007)

Date of U.S. Introduction: First observed on the Pacific coast in the 1930s (Clarke and Therriault 2007)

Means of Introduction: Probably introduced accidentally on the hulls of ships or with imported oysters (Clarke and Therriault 2007)

Impact: Competes with and displaces native species (Clarke and Therriault 2007)

Current U.S. Distribution: Coastal regions of New England and the Western U.S.


Selected Resources:

Council or Task Force

Stop the Invasion: Invasive Tunicate (Jun 2016; PDF | 484 KB)
Washington State Recreation and Conservation Office. Washington Invasive Species Council.
See also: Outreach and Educational Materials - Invasive Species Fact Sheets for more resources


Invasive Species Compendium - Styela clava
CAB International.

Delivering Alien Invasive Species Inventories for Europe: Species Factsheet - Styela clava
European Commission. Sixth Framework Programme.

Non-native Species Information: Leathery Sea Squirt
Great Britain Non-Native Species Secretariat.

Rhode Island Marine & Estuarine Invasive Species Site - Club Tunicate
Narragansett Bay Research Reserve. Coastal Training Program.

NEANS Panel Online Guide - Club Tunicate
Northeast Aquatic Nuisance Species Panel.

The Exotics Guide: Non-native Marine Species of the North American Pacific Coast (Revised Sep 2011) - Styla clava
San Francisco Estuary Institute; Center for Research on Aquatic Bioinvasions.

NOBANIS: Invasive Alien Species Fact Sheet - Styela clava (2010; PDF | 66 KB)
European Network on Invasive Alien Species.
See also: NOBANIS Fact Sheets for invasive alien species of the European region, covering both animals and plants, as well as microorganisms

Global Invasive Species Database - Styela clava (tunicate)
IUCN. Species Survival Commission. Invasive Species Specialist Group.

Federal Government

National Exotic Marine and Estuarine Species Information System (NEMESIS) - Styela clava
Smithsonian Institution. Smithsonian Environmental Research Center. Marine Invasions Research Lab.

International Government

Invasive Sea Squirt (Styela clava) Fact Sheet
National Institute of Water and Atmospheric Research (New Zealand).

Non-Native Species: Styela clava
Joint Nature Conservation Committee (United Kingdom).

State Government

Aquatic Invasive Species: Invasive Tunicate Species Management Program
Washington Department of Fish and Wildlife.


Invasive Tunicate Identification Card: Colonial Tunicate and Club Tunicate (PDF | 1.6 MB)
University of Washington. Washington Sea Grant Program.


Integrated Taxonomic Information System. Styela clava. [Accessed Sep 10, 2014].

Clarke, C.L. and T.W. Therriault. 2007. Biological Synopsis of the Invasive Tunicate Styela clava (Herdman 1881) (PDF | 1.38 MB) Pacific Biological Station, Fisheries and Oceans Canada. Canadian Manuscript Report of Fisheries and Aquatic Sciences 2807.

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Last Modified: Jul 17, 2018
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