Biodiversity & Conservation

Ocnus planci aggregations on sheltered sublittoral muddy sediment



Image Dominic Counsell - Aggregation of Ocnus planci on broken shell and cobbles. Image width ca 40 cm.
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Distribution map

SS.IMU.MarMu.Ocn 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 Rare
Habitat Directive feature (Annex 1) Large shallow inlets and bays

Biotope importance

This biotope is notable for the large aggregations of the sea cucumber Ocnus planci (or Ocnus brunneus). The presence of hard substrata in areas otherwise dominated by sheltered muds allows epifaunal species to colonize the habitat increasing the species richness. The biotope is dominated by suspension feeders, which probably transport primary productivity from the pelagic ecosystem to the benthic ecosystem, although their relative importance in energy flow within the community and surrounding ecosystem is not known.


No species are known to be exploited in this biotope.

Additional information icon Additional information

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This review can be cited as follows:

Tyler-Walters, H. 2002. Ocnus planci aggregations on sheltered sublittoral muddy sediment. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 27/11/2015]. Available from: <>