Biodiversity & Conservation

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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