A sea squirt (Styela clava)

NBN Interactive23-08-2007

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Researched byAnna Neish Refereed byAdmin
AuthorityHerdman, 1881
Other common names- SynonymsStyela mammiculata Herdman, 1881

Summary

Description

A solitary sea squirt with a long club-shaped body, tapering to a slender and tough stalk. The overall height of the sea squirt can reach 12cm and the stalk can be a 1/3 of the total length. The surface of the sea squirt can be leathery with folds and swellings. The siphons at the top (anterior) end are close together.

Recorded distribution in Britain and Ireland

Styela clava is distributed on the south and west coasts of England as far north as Cumbria. It has also been found in Loch Ryan and Androssan marina, Scotland, in Cork and Fenit Harbours, Ireland, and the Channel Isles.

Global distribution

It is a native of the north western Pacific and found in Japan, Korea and Siberia. It is also now found in France, The Netherlands, Denmark and Ireland.

Habitat

Styela clava is found in shallow water on hard surfaces and occurs abundantly in sheltered warm water docks and harbour installations.

Depth range

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Identifying features

  • Body long, narrow and club-shaped.
  • Slender tough stalk can be 1/3 of total length.
  • Total length up to 12 cm.
  • Surface leathery with folds and swellings.
  • Siphons at anterior end close together.
  • 2-4 gonads on left-side and 5-8 on right, each with a long narrow ovary surrounded by male follicles.

Additional information

Styela clava is a non native marine species originally from the north western Pacific. It was found in Plymouth Devon in 1953 (Carlisle, 1954) and was possibly introduced on the hulls of war ships following the end of the Korean war in 1951. Styela clava is a fouling pest on ships hulls and oyster beds, and the transport of oysters and any movement of ships probably aided its rapid dispersal (Eno et al., 1997). The distribution of Styela clava was examined recently by Davis & Davis (2004). They reported another 40 new records of this species in European harbours, including new records in the Channel Isles, France and Spain. A similar sea squirt, Styela gelatinosa has only been found in one location and is easily separated from Styela clava by its narrow base or slight stalk.

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Bibliography

  1. Carlisle, D.B., 1954. Styela mammiculata, a new species of ascidian from the Plymouth area. Journal of the Marine Biological Association of the United Kingdom, 33, 329-334.
  2. Davis, M.H. & Davis, M.E., 2004. New records of Styela clava Herdman, 1882 (Tunicata, Ascidiacea) in Europe. Porcupine Marine Natural History Society Newsletter, 14, 24-27.
  3. Eno, N.C., Clark, R.A. & Sanderson, W.G. (ed.) 1997. Non-native marine species in British waters: a review and directory. Peterborough: Joint Nature Conservation Committee.
  4. Hayward, P., Nelson-Smith, T. & Shields, C. 1996. Collins pocket guide. Sea shore of Britain and northern Europe. London: HarperCollins.
  5. Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.
  6. Millar, R.H., 1970. British Ascidians London: Academic Press.[Synopses of the British Fauna, no. 1.]
  7. Minchin, D., & Duggan, C.B. 1988. The distribution of the exotic ascidian, Styela clava Herdman, in Cork Harbour. Irish Naturalists' Journal, 22,388-393.

Citation

This review can be cited as:

Neish, A.H. 2007. Styela clava 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: http://www.marlin.ac.uk/species/detail/1883

Last Updated: 23/08/2007