Cornish Biodiversity Network  -  Supporting Wildlife Recording

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Cornish Red Data (2009)

The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.

Atrina fragilis - Fan Mussel

Range & Status

Found with its pointed anterior end deeply buried in mud, sand or fine gravel from extreme low water mark to considerable depth (400m). A widely distributed, but rarely encountered, species in Britain. Recorded from the north of Scotland through to the Iberian Peninsula, however it is a predominantly southern and south-western species in the British Isles. Once described as being relatively common about the extreme low water mark on the shores of the Isles of Scilly, it has since undergone a very marked decline in numbers. The most recent records come from south of Dodman Head, south of the Helford Estuary and a single specimen amongst sublittoral Eelgrass Zostera spp. in the Helford Estuary itself. There are apparently fairly large numbers of this species in deep water in the English Channel outside the 12 mile limit off Cornwall (Walker, 1991). This species has been affected by the increase in demersal fishing in recent years. The single specimen in the Helford Estuary is in danger of boats anchoring in the shallow water or collection by divers.

Atrina fragilis is on the UK list of Priority Species, has its own Species Action Plan and has been protected under Schedule 5 of the Wildlife and Countryside Act (1981) since 1998.


I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.

The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.

Cornish Biodiversity Network. 2017.