Ciona savignyi (Solitary sea squirt)

Animal Tunicate/Sea-squirt
Family: Cionidae
Classification: Unlisted Invasive Species

Ciona savignyi next to Spiny Pink Star. Near Union, on south Hood Canal. Photo by Janna Nichols

Ciona savignyi grows near Union, on south Hood Canal. Photo by Georgia Arrow

State aquatic managers ask the public to report sightings of tunicates and other aquatic invasive species. To report sightings contact:

Allen Pleus
A quatic nuisance species coordinator for WDFW
(360) 902-2724

Pam Meacham
WDFW Assistant aquatic nuisance species coordinator
(360) 902-2741


Ciona savignyi is a solitary tunicate (“sea-squirt”) native to the Asian Pacific.  It is not considered native to the Pacific Northwest.   C. savignyi is whitish in color to almost clear.  In fact, it can be so transparent that the organs can be seen within.   It is generally tube-shaped, has two siphons of unequal length that are slightly scalloped at the edges with small yellowish to orange flecks forming at the rim.  C. savignyi is usually found in depths 40 feet  to 75 feet, but can also be found under cover in protected waters on hanging aquaculture rafts, in marinas under docks, pilings, boat hulls and other structures.  C. savignyi can form dense aggregations that aggressively compete with many other organisms including mussels and oysters for food and space.

C. savignyi pumps water in through the inhalant siphon, filters out oxygen and feeds on small organisms such as phytoplankton, zooplankton, oyster and mussel larvae, and other suspended organic materials, and then pumps the water as waste out through the exhalent siphon.  The siphons are able to retract when the animal is disturbed.

Like all sea squirts, C. savignyi is hermaphroditic, meaning that it contains both male and female organs.  However the male and female parts of each individual do not mature at the same time, so it does not self fertilize.  Eggs and sperm are broadcast spawned into the water column producing planktonic, tadpole-like, larvae that can survive for only a few days unless a suitable substrate is found to attach to.  It then metamorphoses into an adult that can reach up to 6 inches in length.

See the Tunicate information page for more information

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