information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

An acorn barnacle (Balanus balanus)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.
Only coastal and marine records shown



A relatively large barnacle of up to 5 cm diameter (typically around 1.5 cm). Balanus balanus has a thick greyish-white, steeply conical shell with prominent longitudinal ridges, a strongly beaked opercular valve (tergum) and a yellow opercular membrane.

Recorded distribution in Britain and Ireland

Widespread in United Kingdom and Irish coastal waters.

Global distribution

Balanus balanus has a boreo-arctic distribution ranging from Long Island Sound in the western Atlantic to around 80°N. B. balanus has also been recorded from the North Pacific including Alaska, British Columbia and the Okhotsk Sea.


Balanus balanus is a cold water species found between low water and 150 m, attaching to hard substrates including rocks and mussels.

Depth range


Identifying features

  • Steeply conical shell.
  • Shell wall with prominent longitudinal ridges.
  • Parietes and calcareous base porous.
  • Strongly beaked tergum.
  • Opercular membrane yellow.

Additional information

No text entered

Listed by

- none -

Further information sources

Search on:



    This review can be cited as:

    Hosie, A.M. 2008. Balanus balanus An acorn barnacle. 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. [cited 20-08-2018]. Available from:

    Last Updated: 10/10/2008