Pacific oyster (Magallana gigas)
|Researched by||Joelene Hughes||Refereed by||Admin|
|Other common names||-||Synonyms||Crassostrea angulata (Lamarck, 1819), Crassostrea gigas (Thunberg, 1793)|
Recorded distribution in Britain and Ireland
Introduced initially in Cornwall, Essex and Wales for mariculture. It has been farmed on around 300 sites throughout England, Scotland, Wales and Northern Ireland. 'Escapees' have established populations in various regions.
Present throughout Europe from Norway to Spain and Portugal on the Atlantic Coast. Present in the USA and south west Canada. It occurs naturally in Japan and south eastern Asia.
Found on the lower shore and shallow sublittoral to a depth of around 80 m.
- An elongate oval shell with a crenulate shell margin.
- The left valve is deeply cupped with a coarse concentric sculpture and has 6 or 7 prominent ribs.
- The flat or slightly convex right valve sits inside the left valve.
- The troughs of the right valve correspond to the ridges on the left valve.
- The shell often overgrows the beaks and umbones.
- The external colour may be off-white to brown with patches or streaks of purple.
- Internally the shell is white with the adductor scar typically purple (mauve).
Additional informationSimilar to Crassostrea virginica although this species lacks the crenulate shell margin and bold ribs of Magallana gigas. Magallana gigas was introduced from Portugal to Essex in 1926 as a commercial crop and has since established itself in the wild. It occurs naturally in Japan and south-east Asia. Magallana gigas is also known as the Portuguese or Japanese oyster.
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Eno, N.C., Clark, R.A. & Sanderson, W.G. (ed.) 1997. Non-native marine species in British waters: a review and directory. Peterborough: Joint Nature Conservation Committee.
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Pauley, G.B., B. van der Raay, and D Troutt 1988. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates. (Pacific Northwest) - - Pacific oyster. [online] http://www.nwrc.gov/publications/specintro.htm, 2002-01-30
Seaward, D.R., 1982. Sea area atlas of the marine molluscs of Britain and Ireland. Peterborough: Nature Conservancy Council.
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Tebble, N., 1976. British Bivalve Seashells. A Handbook for Identification, 2nd ed. Edinburgh: British Museum (Natural History), Her Majesty's Stationary Office.
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Last Updated: 08/05/2008