Biodiversity & Conservation

Mytilus edulis beds on variable salinity infralittoral mixed sediment


<i>%Mytilus edulis%</i> beds on variable salinity infralittoral mixed sediment
Distribution map

SS.SBR.SMus.MytSS recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats
  • UK_BAP

Marine natural heritage importance

Listed under EC Habitats Directive
UK Biodiversity Action Plan
National importance Uncommon
Habitat Directive feature (Annex 1) Reefs
Large shallow inlets and bays

Biotope importance

Dense beds of suspension feeding bivalves are important in nutrient cycling in estuarine and coastal ecosystems, transferring phytoplankton primary production and nutrients to benthic secondary production (pelagic-benthic coupling) (Dame, 1996). Mussel beds also stabilize the sediment and generate organically rich deposits (mussel mud) that provides food for numerous deposit feeding invertebrates both within the deposit and the surrounding area (Holt et al., 1998). Mytilus spp. beds are, therefore, probably important to the functioning of their entire ecosystem.

Subtidal mussel beds in the Baltic Sea were a major food source for the flounder (Platichthys flesus) but probably of only minor importance for eelpout (Zoarces viviparus) and cod (Gadus morhua) (Kautsky, 1981). 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 edulis beds, including subtidal beds are probably important food sources for eider duck, which consume large numbers of mussels, primarily over winter. Raffaelli et al. (1990) recorded the removal of 4500 mussels /m² (within the preferred size of 10-25mm) within 60 days by a flock of 500 eider. Loss of stock may have significant effects on other species, e.g. in the Dutch Wadden Sea in 1990 the mussel stocks fell to unprecedented low levels resulting in death or migration of eiders, and oystercatchers seeking alternative prey such as Cerastoderma edule, Mya arenaria, and Macoma baltica.


Mussels have been harvested for food and bait since early times. British mussel production is relatively small comprising only 5% of total European Community production (Edwards, 1997). Edwards (1997) notes that the commercial development of natural beds is hampered by sporadic and unpredictable recruitment. The extent to which this biotope is exploited is uncertain.

Additional information icon Additional information

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This review can be cited as follows:

2001. Mytilus edulis beds on variable salinity infralittoral mixed sediment. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 26/11/2015]. Available from: <>