Description: A large solitary seasquirt with a soft gelatinous cylindrical body and conspicuous oral and atrial siphons. The test is semi-transparent, the animal greenish with orange or yellow bars on the branchial sac. At some times or in some places all individuals will have the whole test deep orange in colour. The margins of the siphons have characteristic yellow marks. 50-80mm tall.

Habitat: Often abundant and conspicuous in sheltered areas with some current, often on man-made structures, wrecks, buoys, ropes, etc. Also a component of moderately exposed rocky shallow sublittoral communities, but usually only as solitary individuals.

Ecology: Relatively short-lived and fast-growing but not seasonal in most habitats. Ciona populations show tremendous fluctuations of numbers over a period of years and may be very opportunistic, rapidly colonising new structures or areas cleared by abnormal fluctuation of temperature or salinity.

Distribution: Widely distributed all round the British Isles and reported from many parts of the world.

Similar Species: The soft texture and yellow marks around the siphons are totally characteristic of this species.

Key Identification Features:

• Tall, soft body with large siphons.
• Scalloped yellow markings around margins of siphons.

Distribution Map from NBN: Ciona intestinalis at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Ciona intestinalis at iNaturalist World Species Observations database.

WoRMS: Ciona intestinalis at World Register of Marine Species. Accepted name: Ciona intestinalis (Linnaeus, 1767). AphiaID: 103732.

Classification: Biota; Animalia; Chordata; Tunicata; Ascidiacea; Phlebobranchia; Cionidae; Ciona