Species Information

Club tunicate (Styela clava) Club tunicate (Styela clava)
N. Balcom, CT Sea Grant
Club tunicate (Styela clava)
N. Balcom, CT Sea Grant
Club tunicate
Styela clava

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• First observed in Long Island Sound in 1973; by 1988, its range expanded northward to Maine and southward to Connecticut


• Yellowish-gray to reddish-brown
• Club-shaped with two siphons
• Tough, leathery, bumpy exterior; often covered with other organisms
• Up to 8 in (20 cm) tall with stalk approximately 1/3 of its total length
• Fast-growing, prolific breeder


• Grows on hard surfaces such as pilings
• Shallow water below low-tide line

Known Distribution in the Northeast

• Prince Edward Island, and Maine to New Jersey
• Native to Sea of Okhotsk south to Shanghai


• Aggressive competitor for living space and food
• Can replace native species of invertebrates
• Occurs by the tens of thousands in areas previously occupied by the blue mussel, Mytilus edulis, in parts of southern New England

Club tunicate (Styela clava)
MIT Sea Grant College Program

Protecting the marine and freshwater resources of the Northeast from invasive aquatic nuisance species