Styela clava

Asian Stalked Tunicate

Styela clava

Common name:

Asian Stalked Tunicate

Scientific name:

Styela clava

Alternative common names:

Club Sea Squirt, Club Tunicate, Korean Sea Squirt, Leathery Tunicate


Description:

Styela clava is a solitary tunicate with a leathery, but thin, and bumpy tunic. Its body is cylindrical or club-shaped and narrows posteriorly to a stalk that is anchored to the substrata by a disk shaped holdfast. The wrinkled or creased looking stalk is often 20-50% of the total body length. Styela clava can grow up to 150 mm in length. Colors can range from yellowish to reddish to brownish. The oral and atrial siphons are located close together and are directed anteriorly. Both siphons have four lobes and appear striped with alternating dark and light brownish to purplish bands. It is native to the Northwest Pacific, from Shanghai to the Sea of Okhotsk and the Southeastern Bering Sea and has been introduced to both coasts of North America and to Europe, Australia and New Zealand.

Club Sea Squirt, Club Tunicate, Korean Sea Squirt, Leathery Tunicate

Additional Information


Where does this species come from?

It is native to the Northwest Pacific, from Shanghai to the Sea of Okhotsk and the Southeastern Bering Sea and has been introduced to both coasts of North America and to Europe, Australia and New Zealand.

What is its invasive status in South Africa?

NEMBA 2020 2020 Category XX: Styela clava has not been recorded in South African waters.

Where in South Africa is it a problem?

Styela clava has not been recorded in South African waters.

How does it spread?

Styela clava introduced through ship fouling and transport with oysters.

Why is it a problem?

S. clava adversely affects aquaculture production by fouling cultured species and equipment. It can also grow in dense clumps, dominating large patches, and outcompeting other fouling species.

What does it look like?

Description: Styela clava is cylindrical or club-shaped and narrows posteriorly to a stalk supported by a disk-shaped holdfast. It has a leathery, but thin, and bumpy tunic. Colors can range from yellowish to reddish to brownish. Styela clava can grow up to 150 mm in length.

Habitat: Vessel hull, oyster reef, marinas and docks, coarse woody debris and rocks.

Breeding: Solitary ascidians release both, eggs and sperm to the atrial chamber. Eggs may be self-fertilized or fertilized by sperm from nearby animals, but many species have a partial block to self-fertilization.