Biodiversity & Conservation

Polydora sp. tubes on upward-facing circalittoral soft rock



Image Keith Hiscock - Polydora sp. tubes on upward-facing circalittoral soft rock, with the sponge Suberites sp. also present. Image width ca 2 m.
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Distribution map

CR.MCR.SfR.Pol recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

Marine natural heritage importance

Listed under EC Habitats Directive
National importance Not available
Habitat Directive feature (Annex 1) Reefs
Large shallow inlets and bays

Biotope importance

Polydora ciliata is a serious pest of oysters and mussels, but invades only the shell and does not eat the soft tissue. When infestation is heavy, the shell is weakened and this makes the mollusc more susceptible to predation by crabs. Occasionally, the inner surface of the shell is damaged by the worms and the mollusc secretes a nacreous substance to seal the perforation. The resulting blisters are an indication of attack by the species, and mussels heavily infested with the polychaete have reduced flesh content, possibly as a result of some impact on the metabolism of the mussel.


The biotope is unlikely to be exploited because Polydora ciliata has no commercial importance.

Additional information icon Additional information

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This review can be cited as follows:

Hill, J.M. 2001. Polydora sp. tubes on upward-facing circalittoral soft rock. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 01/12/2015]. Available from: <>