Biodiversity & Conservation

Mytilus edulis and Fucus vesiculosus on moderately exposed mid eulittoral rock



Image David Connor - Mytilus and fucoids. Image width ca 80 cm.
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Distribution map

LR.MLR.MF.MytFves 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 Scarce
Habitat Directive feature (Annex 1) Reefs
Large shallow inlets and bays

Biotope importance

Suspension feeding Mytilus beds can deplete the seston (organic particulates) available downstream of them and are probably important in energy flow within the wider ecosystem (Holt et al., 1998). Dense beds of bivalve suspension feeders increase turnover of nutrients and organic carbon in estuarine (and presumably coastal) environments by effectively transferring pelagic phytoplanktonic primary production to secondary production (pelagic-benthic coupling) (Dame, 1996).

Mussel eggs and larvae from mussel beds (including subtidal beds) are probably an important food source for herring larvae and other zooplankton (Kautsky 1981; Seed & Suchanek, 1992). The Mytilus edulis beds probably also form an important food source for starfish and decapod crustaceans, and may provide refuge for others (see ecology). Mytilus reefs and beds are important food sources for wildfowl, and Mytilus is a staple food for oystercatchers and eider ducks. For example, unpredecentedly low stocks of Mytilus edulis in the Dutch Wadden Sea resulted in eider ducks either dying or leaving the area, while oystercatchers sought alternative food, depleting stocks of Mya arenaria and Cerastoderma edule (Holt et al, 1998). Although intertidal rocky shore beds are probably less important than sedimentary shore beds, they may still be of significant importance for resident local populations of wildfowl.


Large Mytilus edulis reefs and beds have been the subject of fisheries for at least the past 100 years, and Mytilus edulis is also the subject of cultivation (Holt et al, 1998). Small, rocky shore beds exemplified by this biotope are probably not subject to large scale exploitation. However, Holt et al. (1998) noted that small, accessible mussel beds may be exploited locally by anglers for bait. For example, a small bed close to a road on Anglesey was almost eliminated by anglers and bait diggers over a period of years (see sensitivity).

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This review can be cited as follows:

Tyler-Walters, H. 2002. Mytilus edulis and Fucus vesiculosus on moderately exposed mid eulittoral rock. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 29/11/2015]. Available from: <>