A bristleworm (Chaetozone setosa)

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



Chaetozone setosa has a relatively thin cylindrical body that narrows posteriorly. The overall body length is 20-25 mm with 70-90 segments (chaetigers). The head bears a pointed, eyeless prostromium with two extremely long, wrinkled fragile palps on the first segment. Typically grey, brownish or bluish-black in colour. Long finger-like gills are present along the initial half of the body from the first segment. At the posterior end of the body, stout pointed chaetea form transverse series latterally. Toward the end of the body the chaetae increase in number and almost encircle the entire segment.

Recorded distribution in Britain and Ireland

This species can be found around the coasts of Britain and Ireland.

Global distribution



Chaetozone setosa is common on muddy and gravel bottoms in the shallow sublittoral.

Depth range


Identifying features

  • Cylindrical body with 70-90 segments (chaetigers).
  • Body length 20-25 mm.
  • Head bears pointed, eyeless prostomium.
  • Stout, pointed chaetae towards the end of the body; latter chaetae almost encircle the entire segment.
  • Gills on at least 20 initial segments.

Additional information

This species is a sedentary worm feeding on detritus using its long, wrinkled fragile palps. There are several species confused under this name in UK waters (Howson & Picton, 1997).

Listed by

- none -


  1. Ball, B.J., Fox, G. & Munday, B.W., 2000. Long- and short-term consequences of a Nephrops trawl fishery on the benthos and environment of the Irish Sea. ICES Journal of Marine Science, 57, 1315-1320.

  2. Bruce, J.R., Colman, J.S. & Jones, N.S., 1963. Marine fauna of the Isle of Man. Liverpool: Liverpool University Press.

  3. Chambers, S.J., 2000. A redescription of Chaetozone setosa Malmgren, 1867 including a definition of the genus, and a description of a new species of Chaetozone (Polychaeta: Cirratulidae) from the northeast Atlantic. Bulletin of Marine Science, 67, 587-596.

  4. Christie, G., 1985. A comparative study of the reproductive cycles of three Northumberland populations of Chaetozone setosa (Polychaeta: Cirratulidae). Journal of the Marine Biological Association of the United Kingdom, 65, 239-254.

  5. Curtis, M.A., 1977. Life cycles and population dynamics of marine benthic polychaetes from the Disko Bay area of W. Greenland. Ophelia, 16, 9-58.

  6. Frid, C.L.J., Clark, R.A. & Hall, J.A., 1999. Long-term changes in the benthos on a heavily fished ground off the NE coast of England. Marine Ecology Progress Series, 188, 13-20.

  7. Hayward, P., Nelson-Smith, T. & Shields, C. 1996. Collins pocket guide. Sea shore of Britain and northern Europe. London: HarperCollins.

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

  9. Hily, C., 1987. Spatio-temporal variability of Chaetozone setosa (Malmgren) populations on an organic gradient in the Bay of Brest, France. Journal of Experimental Marine Biology and Ecology, 112, 201-216.

  10. 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.]

  11. Kenchington, E.L.R., Prena, J., Gilkinson, K.D., Gordon, D.C., Macisaac, K., Bourbonnais, C.; Schwinghamer, P.J., Rowell, T.W., McKeown, D.L. & Vass, W.P., 2001. Effects of experimental otter trawling on the macrofauna of a sandy bottom ecosystem on the Grand Banks of Newfoundland. Canadian Journal of Fisheries and Aquatic Sciences, 58, 1043-1057.

  12. 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.

  13. Sparks-McConkey, P.J. & Watling, L., 2001. Effects on the ecological integrity of a soft-bottom habitat from a trawling disturbance. Hydrobiologia, 456, 73-85.

  14. Tuck, I.D., Hall, S.J., Robertson, M.R., Armstrong, E. & Basford, D.J., 1998. Effects of physical trawling disturbance in a previously unfished sheltered Scottish sea loch. Marine Ecology Progress Series, 162, 227-242.


  1. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.

  2. Environmental Records Information Centre North East, 2018. ERIC NE Combined dataset to 2017. Occurrence dataset: http://www.ericnortheast.org.ukl accessed via NBNAtlas.org on 2018-09-38

  3. NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.

  4. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-07-14

  5. South East Wales Biodiversity Records Centre, 2018. SEWBReC Worms (South East Wales). Occurrence dataset: https://doi.org/10.15468/5vh0w8 accessed via GBIF.org on 2018-10-02.


This review can be cited as:

Rowley, S.J. 2006. Chaetozone setosa A bristleworm. 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 14-07-2024]. Available from: https://www.marlin.ac.uk/species/detail/2099

Last Updated: 10/10/2006