BIOTIC Species Information for Atrina fragilis
Researched byDr Harvey Tyler-Walters Data supplied byMarLIN
Refereed byDr Dan Minchin
Distribution and Habitat
Distribution in Britain & IrelandPredominantly southern and western shores of the UK from North Scotland to the Iberian Peninsula, including the Channel Isles (see additional information below). Recorded at Milford Haven.
Global distributionNorthern UK to Iberian Peninsula and the Adriatic Sea.
Biogeographic rangeNot researched Depth rangeLWS to 400m
MigratoryNon-migratory / Resident   
Distribution Additional InformationDistribution
Specimens occur as solitary individuals or localized patches of small groups of individuals. Records for Ireland were supplied by Julia Nunn and the Centre for Environmental Data and Recording (CEDaR). Records of fan mussel shells, and records before 1950, are more widespread than shown in the above map, which only shows live records after 1950.

Atrina fragilis was recorded in Zostera sp. beds in the Isles of Scilly, however specimens have not been found since the Zostera sp. beds were lost (Turk 1982; Turk & Seaward 1997). This species was more common in scallop areas in the early 1900s. Presumably trawling and dredging of theses formerly populated regions is the reason for the decline of this species (Minchin pers. comm.). Dredging of a Pecten maximus bed off Glengad Head, Ireland, after 1975, removed many live specimens of Atrina fragilis in scallop dredges and the population of fan mussels is thought to have been destroyed by subsequent dredging (Anon 1999c).

The species is known from weak to moderately strong currents, for example in Knightstown, Valentia Island the population is exposed to >2 knots on spring tides (Dan Minchin pers. comm.). Although usually found at full salinities it may be exposed to reduced or variable salinities for brief periods (Dan Minchin pers. comm.).

Substratum preferencesGravel / shingle
Muddy gravel
Muddy sand
Fine clean sand
Sandy mud
Coarse clean sand
Physiographic preferencesOffshore seabed
Ria / Voe
Enclosed coast / Embayment
Biological zoneSublittoral Fringe
Upper Infralittoral
Lower Infralittoral
Upper Circalittoral
Lower Circalittoral
Wave exposureSheltered
Very Sheltered
Tidal stream strength/Water flowModerately Strong (1-3 kn)
Weak (<1 kn)
SalinityFull (30-40 psu)
Habitat Preferences Additional Information
Distribution References Tebble, 1976, Woodward, 1985, Anonymous, 1999(c), Seaward, 1990, Seaward, 1982, Turk, 1982, Turk & Seaward, 1997, Moore, 2002, Simunovic et al., 2001,
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