Ciona intestinalis is a solitary ascidian which is up to 15 cm high. This upright cylindrical
sea-squirt has a smooth soft test. It is translucent and its colour varies from white to yellow. Muscular
bands, branchial sac and intestine are visible through the test. The edges of the siphons have a yellow margin.
Oral and atrial siphons are contiguous and terminal. The oral siphon has 8 lobes and the
atrial one has 6 lobes. Yellow sea-squirts often live in groups attached to rocks, piles, hulls. It can be
common in harbours because this species seems to bear polluted waters.
It is found from low water level to 50 m deep in the Atlantic Ocean, the English Channel, the North Sea, the
Baltic sea and the Mediterranean Sea.
(source : European Register of Marine Species)
Test : or tunic: thick layer secreted by the mantel containing cellulose and protecting the animal.
Oral siphon : Opening by which water is drawn in the ascidian.
Atrial siphon : Opening through which water is expelled.
Ciona intestinalis
Yellow sea-squirt
Ciona intestinalis
View of the branchial sac
Ciona intestinalis
Young specimen
Top photograph :
© Wilfried Bay-Nouailhat. Published with author's kind permission :
Ciona intestinalis,
Bay of Concarneau, South-Brittany, West of France. Depth 5 meters.
Bottom photographs : © Wilfried Bay-Nouailhat. Published with author's kind permission :
Ciona intestinalis, Yellow sea-squirt. Baie de Concarneau, South Brittany, West of France. Depth 4 meters.
© Wilfried Bay-Nouailhat. Published with author's kind permission :
Ciona intestinalis, View of the branchial sac. Baie de concarneau, South Brittany, West of France. Depth 11 meters.
© Wilfried Bay-Nouailhat. Published with author's kind permission :
Ciona intestinalis, Young specimen. Baie de Concarneau, South Brittany, West of France. Depth 4 meters.
Text : Anne Bay-Nouailhat © 2005-2020.
Translation : Anne Bay-Nouailhat © 2007-2020.
