An erect bryozoan (Cellaria fistulosa)

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



Cellaria fistulosa grows to around 5 to 6 cm high and forms yellowish cream-coloured clumps. It is easily identifiable by its hexagonally shaped zooids, which can be seen using a hand lens. These zooids are usually in a series of 5 or 6 that grow in a column, with each zooid in contact with the one above and below it. The part of the stem between branches (internodes) is cylindrical in shape and between 0.4 and 0.8 mm long. These internodes narrow towards the base of the colony but are not club-shaped. The internal feeding polyp (polypide) has 15 tentacles. The avicularium (a specialized zooid) is one-third of the length of a zooid, rounded to quadrangular in shape and is positioned between the zooids. The colonies branch frequently to form a turf. The brood chamber (ovicell) opening is small, rounded and in the centre. Embryos are yellow in colour and present from September to May.

Recorded distribution in Britain and Ireland

Recorded around Britain and Ireland, but most common in the Irish Sea and western coasts and sparsely recorded along the east coast of Britain.

Global distribution

Occurs in warm, temperature seas. Recorded off northern Norway, the North Sea, the Kattegat, the Gulf of Venice, the Aegean Sea and off the coast of Izmir in Turkey. Also recorded in the Mediterranean in the Balearic Islands, the south of France and Spain. 


Sublittoral attached to hard substrata. 

Depth range

0 – 150 m (occasional records from 180 – 400 m)

Identifying features

  • Forms clumps that are 5 to 6 cm high. 
  • Can be identified by its hexagonal-shaped zooids that are visible with a hand lens. 
  • Embryos are yellow in colour and visible from September to May. 
  • Internodes are between 0.4 and 0.8 mm long and not club-shaped. 
  • Colonies branch frequently to form an extensive diffuse growth and are yellowish to cream-coloured. 

Additional information

It can be distinguished from Cellaria sinuoisa as Cellaria fistulosa has a more slender appearance due to a smaller internode length and smaller zooids. Eggleston (1963) suggested that the colonies of this species are closely associated with clumps of hydroids through the anchoring of a hair-like structure that forms a root and anchoring point (rhizoids).

Listed by

- none -


  1. Eggleston, D., 1963. The Marine Polyzoa of the Isle of Man. Ph.D. Thesis, University of Liverpool, Liverpool.

  2. Hayward, P.J. & Ryland, J.S. 1998. Cheilostomatous Bryozoa. Part 1. Aeteoidea - Cribrilinoidea. Shrewsbury: Field Studies Council. [Synopses of the British Fauna, no. 10. (2nd edition)]

  3. Porter, J., 2012. Seasearch Guide to Bryozoans and Hydroids of Britain and Ireland.   Ross-on-Wye: Marine Conservation Society.


  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: 2024-04-25


This review can be cited as:

Burdett, E.G. 2023. Cellaria fistulosa An erect bryozoan. In Tyler-Walters H. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25-04-2024]. Available from:

Last Updated: 04/10/2023