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Native oyster beds
In shallow water (usually less than about 10m deep) on fine, muddy sand, native oysters (Ostrea edulis) can be found in large numbers.
Native oysters © JNCC/Keith Hiscock
Where this happens, the oysters themselves and the dead shells amongst them form extensive beds, which become home to many other marine creatures, including crabs, worms, sea snails, sponges, sea urchins, and seaweed. Nearly 250 different animals and plants have been found in oyster beds, although not all in the same place at once. These other creatures use the oyster beds in different ways: as a surface to attach themselves to, or, in the case of small or young fish for example, as somewhere to hide from predators.
There are a number of threats to native oyster beds, including pollution and parasites which can wipe out oyster beds, as has happened throughout Europe. The invasion of slipper limpets has also affected native oysters, as their presence makes it more difficult for the oysters to become established. The Pacific oyster, again introduced from abroad, can also threaten native oysters by competing for space and food. Another introduced species, a snail called the American oyster drill, makes its home in oyster beds and feeds entirely on the young of the native oysters.
The biggest threat to native oysters is, however, overfishing. Over 700 million oysters were consumed in London alone in 1864, but 100 years later total countrywide landings fell to just 3 million. The numbers of native oysters have never recovered.
Brief description of European distribution
The native oyster is widely distributed around UK coasts, particularly in the south and west, but large beds are now sparsely distributed. The main stocks are found in the Thames Estuary, The Solent, River Fal, the west coast of Scotland and Lough Foyle. The oyster’s wider European range extends from the Norwegian Sea to the Atlantic coast of Morocco, and into the Mediterranean and Black Sea.
Natural native oyster beds have become increasingly rare in the North Sea, and the populations in deeper waters in the southern North Sea disappeared during the 19th and 20th centuries.
Conservation status / need
UKBAP Priority Species
OSPAR List of Threatened and/or Declining Species and Habitats (Region II – Greater North Sea)
Species of principal importance for the purpose of conserving of biodiversity under the Natural Environment and Rural Communities Act 2006
Nationally scarce habitat
Further information sources
Native oyster - Ostrea edulis - General information
(MarLIN)
Ostrea edulis (Conchological Society of Great Britain and Ireland)
Ostrea edulis (Marine Species Identification Portal)
Ostrea edulis (Fisheries and Aquaculture Department)
Ostrea edulis beds (NBN Gateway)
Ostrea edulis beds on shallow sublittoral muddy sediment (MarLIN)
Interesting fact
Over 700 million oysters were consumed in London alone in 1864, but 100 years later total countrywide landings fell to just 3 million. Oysters were once the ‘poor man’s food’ – they are now an expensive delicacy.
