Vase Tunicate

Vase Tunicate, or Ciona intestinalis, is a solitary tunicate with a cylindrical, gelatinous body, up to 14 cm long. The soft, smooth translucent tunic (outer skin) is pale yellow or green in colour with orange body parts visible through the outer skin.

This species grows in dense aggregations on any floating or submerged substrate, particularly artificial structures like pilings, aquaculture gear, floats and boat hulls in the lower intertidal to subtidal zones. The tunicate often grows with or on other fouling organisms. While the vase tunicate is a hermaphroditic broadcast spawner it can not self-fertilize. Eggs and sperm once released can stay in the water column for 1 or 2 days while the larvae are free-swimming for 2 to 10 days.

(Photo credit: D. Mouland, DFA)

Means of introduction

Vase Tunicate is thought to be spread mainly through hull fouling. Since it’s larvae can live for up to 10 days this species may also be transferred through the release of bilge or ballast water.

Management of the species

Fish and shellfish harvesters should avoid transferring harvested shellfish and fishing gear to another area. Gear should be thoroughly dried before transfer. Boat hulls should be inspected and, if necessary, well cleaned and disinfected with bleach or vinegar then dried before moving to other areas. Any organisms removed from boat hulls or gear should be disposed of on land. Bilge water should be released on land or disinfected. Report sightings by using the contact information on the main AIS page.

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