These small, blue mussels (Mytilus edulis) are a common sight on UK coasts. They can form extensive beds, with living and dead mussels, sand and mud all bound together by the mussels’ sticky ‘beards’ of byssus threads. Blue mussel beds occur mostly on the lower shore between the tides or permanently submerged in shallow water.
Mussel beds provide an important food source for wintering waders. When beds were lost from parts of Holland in 1990, the eider duck numbers decline significantly. Otters may also get some of their food supply from blue mussel beds, and the ‘mussel mud’ formed by the blue mussels’ waste is an important source of nutrients for animals living within the seabed.
Blue mussel beds have a particularly important role where they occur on soft seabeds, as they provide a hard surface in otherwise muddy or sandy areas. This attracts and supports a greater range of marine life than would otherwise be found there. 133 different animals and plants have been recorded in blue mussel beds, including seaweeds, anemones, barnacles, sea snails, crabs, starfish and worms.
The threats to blue mussel beds include their removal for food or bait, and the damage caused by mobile fishing gear, anchoring or mooring chains, or, for beds found between the tides, by trampling. They are also at risk from shoreline building developments, dredging, and pollution.
Blue mussel beds may take at least five years to recover from damage.
Blue mussels are widespread on the shore and in shallow water around the coasts of the UK and Europe. Significant beds of blue mussels on soft sea beds are found in scattered locations within this broad range. Conservation status / need UKBAP Priority Habitat OSPAR List of Threatened and/or Declining Species and Habitats (Region II – Greater North Sea, and Region III – Celtic Sea) Blue mussel beds can also be key features of habitats listed in Annex I of the Habitats Directive
Mytilus edulis (FAO)
Mytilus edulis (Marine Species Identification Portal)
Mytilus edulis (WoRMS)
The blue mussel can survive at temperatures as low as -10°C.