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Underwater photograph of two sea vase sea squirts

(Photo: Claire Goodwin)

Sandy Island

Sea Vase

Ciona intestinalis

This large solitary sea squirt can be up to 15 centimetres long. It is white, pale yellow, or pale green and has yellow markings on its siphons (the openings at the top of the sea squirt). Out of water it contracts to a jelly-like blob. As the common name suggests, it might squirt you from its siphon when lifted from the water!


Linnaeus, 1767

Classification Details

Phylum: Chordata (chordates); Subphylum: Tunicata (tunicates); Class: Ascidiacea (sea squirts).


Grow on bedrock and boulders. Also found on man-made structures such harbour walls, pier pilings, and aquaculture cages. This is a non-native species to Canada. It comes from Europe and arrived in New Brunswick in 1852. It is becoming very common in the Bay of Fundy. It can cause problems for native species and industries like aquaculture.


Suspension feeders - feed on small particles in the seawater including plankton and detritus. They suck in water through their inhalant siphons and trap particles from the seawater in a mucus net that lines the pharynx. The net is then made into a mucus rope to pass food to the stomach.


Hermaphrodites – individuals are both male and female. They release sperm and eggs through their exhalant siphons. Fertilization occurs in the seawater. They can chemically sense when sperm from another sea vase is present in the water, and this triggers egg release. About a day after fertilization, a tadpole-like larvae forms. It swims in the seawater for two to five days and then uses special adhesive glands in the front of its head to glue itself to the seabed. Once attached, it develops into an adult.

Fun Facts

It is hard to believe it but these little blobs of jelly are related to humans and other vertebrates. The larvae have a dorsal nerve cord, and adult sea squirts have a well-developed heart and circulatory system.


Carver CE, Mallet AL, Vercaemer B (2006) Biological synopsis of the solitary tunicate Ciona intestinalis. Canadian Manuscript Report of Fisheries and Aquatic Sciences 2746: v + 55 p.

Jackson A (2008) Ciona intestinalis A sea squirt. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on–line]. Plymouth: Marine Biological Association of the United Kingdom. Available from: Accessed online 20 January 2020.

Shenkar N, Gittenberger A, Lambert G, Rius M, Moreira da Rocha R, Swalla BJ and Turon X (2020). Ascidiacea World Database. Ciona intestinalis (Linnaeus, 1767). Accessed through: World Register of Marine Species at: Accessed online 20 January 2020.

Underwater photograph of two sea vase sea squirts