Orange sea grapes (Stolonica socialis)

Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help



Stolonica socialis forms clusters which are connected by branch-like stolons that form the base. The zooids are ovoid or rectangular and are up to 2 cm in height. Stolonica socialis is most consistently orange but can be yellow or brown in colour. The small siphons are close together at the upper end of the zooid. The test is smooth with little or no sand adhering to it, although the stolons are often sand coated.

Recorded distribution in Britain and Ireland

Stolonica socialis is recorded from the western English Channel around to north Wales, and in north-west and south-east Ireland.

Global distribution

Stolonica socialis is recorded south to Brittany but probably extends farther south


On subtidal rocks on the open coast, often in current swept areas.

Depth range


Identifying features

  • Forms clusters connected by stolons
  • Zooids ovoid or rectangular.
  • Most consistently orange, may be yellow or brown.
  • Small siphons, close together at upper end of zooid.
  • Smooth test.

Additional information

Stolonica socialis may be confused with the baked bean ascidian, Dendrodoa grossularia, or a smaller sea squirt Distomus variolosus. The internal anatomy is important when distinguishing between species (Millar, 1970).

Listed by

- none -


  1. Berrill, N.J., 1950. The Tunicata with an account of the British species. London: Ray Society.

  2. Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.

  3. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  4. JNCC (Joint Nature Conservation Committee), 1999. Marine Environment Resource Mapping And Information Database (MERMAID): Marine Nature Conservation Review Survey Database. [on-line]

  5. Millar, R.H., 1970. British Ascidians London: Academic Press.[Synopses of the British Fauna, no. 1.]

  6. Picton, B.E. & Costello, M.J., 1998. BioMar biotope viewer: a guide to marine habitats, fauna and flora of Britain and Ireland. [CD-ROM] Environmental Sciences Unit, Trinity College, Dublin.


  1. NBN (National Biodiversity Network) Atlas. Available from:

  2. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-06-20


This review can be cited as:

Ager, O.E.D. 2007. Stolonica socialis Orange sea grapes. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 20-06-2024]. Available from:

Last Updated: 22/08/2007