BIOTIC Species Information for Musculus discors
Researched byLizzie Tyler Data supplied byUniversity of Sheffield
Refereed byThis information is not refereed.
Distribution and Habitat
Distribution in Britain & IrelandCommon around most of the British Isles from Shetland to the Channel Isles.
Global distributionA panartic bivalve, found from the Arctic Circle south through the Bering Sea to Japan or to the Puget Sound in the Pacific or south to New York or Madeira in the Atlantic, including the western Baltic and Mediterranean.
Biogeographic rangeNot researched Depth range
MigratoryNon-migratory / Resident   
Distribution Additional Information

Musculus discors forms gregarious clumps on the holdfasts of seaweeds, especially Corallina officinalis, Fucus spp. Laminaria spp. and Desmarestia sp. On laminarians, Musculus discors may cover the holdfast and bottom part of the stipe (Jeffreys, 1863; Ockelmann, 1958; Tebble, 1976). Small specimens (<20mm) were reported nestled in interstices between barnacles and the old holdfasts of tunicates (MacGinitie, 1955). Merrill & Turner (1963) found Musculus discors fouling the upper surface of the sea scallop Placopecten magellanicus.

Most records reported Musculus discors in the shallow subtidal to depths of up to 50m in the British Isles. However, it has been reported to be abundant above 30-40m in east Greenland, to form a well developed community at 60-100m in the Fosse de la Hague in the English Channel (Cabioch, 1968), to occur from 0 -374m in the Barents Sea (Ockelmann, 1958), and to be common in most trawls from 130-741 ft (ca 39-225m) at Point Barrow, Alaska (MacGinitie, 1955).

Musculus discors occasionally forms dense aggregations, especially in strong tidal streams, covering rock surfaces, forming the biotope MCR.Mus.

Substratum preferencesAlgae
Large to very large boulders
Small boulders
Gravel / shingle
Physiographic preferencesOpen coast
Strait / sound
Ria / Voe
Enclosed coast / Embayment
Biological zoneLower Eulittoral
Sublittoral Fringe
Upper Infralittoral
Lower Infralittoral
Upper Circalittoral
Wave exposureExposed
Moderately Exposed
Very Sheltered
Extremely Sheltered
Tidal stream strength/Water flowStrong (3-6 kn)
Moderately Strong (1-3 kn)
Weak (<1 kn)
SalinityVariable (18-40 psu)
Full (30-40 psu)
Habitat Preferences Additional Information
Distribution References Thorson, 1935, Tebble, 1976, Fish & Fish, 1996, Baldock et al., 1998, Könnecker & Keegan, 1983, Ockelmann, 1958, Thorson, 1946, MacGinitie, 1955, Murray, E. et al., 1999, Thorpe, 1998, Könnecker, 1977, Cartlidge & Hiscock, 1980, Bruce et al., 1963, Seaward, 1990, Brazier et al., 1999,
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