1st September 2002
Nationwide search begins for elusive native oyster
A comprehensive survey of Scotland's native oysters is set to go ahead this year, in an effort to understand how to protect the rare species.
Scottish Natural Heritage (SNH) will commission a study of coastal areas around Scotland to investigate the current population of native oysters, which appear to have declined significantly in Scottish waters over the 20 th century. The survey, which was announced during Scottish Biodiversity Week, will aim to provide a clearer picture of the abundance, distribution and reproductive biology of native oysters in Scotland and help to develop appropriate advice for conservation management.
The native or flat oyster (Ostrea edulis), once a common delicacy on restaurant menus, is these days a rarity, since supplies have declined substantially in UK waters in recent decades.
Most oysters now served up in Scotland are farmed, and the species favoured for farming throughout Europe is the pacific oyster. The native oyster once supported a significant fishery in the Firth of Forth but although dead shells can commonly be seen, no live animals have been found in recent surveys. Scientists are unclear as to how much the species has suffered elsewhere, although they are aware of scattered populations found in sea lochs on the West coast of Scotland, which probably represent a UK stronghold. However, there has been concern in the last two years about the level of illegal fishing experienced at a number of isolated oyster populations in Argyll.
David Donnan, Maritime Advisory Officer at SNH said:" This survey gives us the opportunity to find out what is happening to the oyster population in Scotland and what we can do to help it recover. If oysters are sustainably managed they can be an important economic resource for Scotland as well as a flourishing part of the ecosystem."
Stock abundance of the native oyster was probably greatest in the 18 th and 19 th centuries, when there were large offshore oyster grounds in the southern North Sea and the Channel, producing up to 100 times more than today's 100-200 tonnes. The main UK stocks are now located in the rivers and flats bordering the Thames Estuary, the Solent, River Fal, the West coast of Scotland and the Lough Foyle.
Overfishing of native oyster stocks was one aspect known to contribute to the decline of native oysters, but pollution, lack of stock management and disease may also be important factors. The species is rapidly fished out because it is relatively long-lived and reproduces sporadically, so recovery from over-exploitation can take a very long time. Native oysters are the subject of a UK Biodiversity Action Plan and this survey is a significant step in taking the action plan forward in Scotland.
The survey is part of SNH's drive to boost biodiversity in Scotland and was announced to celebrate this year's Scottish Biodiversity Week, which is held between 31 st August - 8 th September. The nine days of events and activities are organised by environmental and community groups, government agencies and individuals and aim to raise awareness about Scotland's rich variety of animals, plants, fungi, microbes and the habitats in which they live. Over 100 events are planned across the country, ranging from guided walks, talks, interactive games and exhibitions to mushroom hunting, tree and wildflower planting.
This is the second year the week has run and coincides with the World Summit on Sustainable Development, which is being held in Johannesburg and will include a civic delegation from Scotland led by First Minister Jack McConnell.
For more information contact: Sarah Roe, Press and PR officer, SNH
Tel: 0131 446 2270
Notes to Editors
- SNH is the Scottish Executive's statutory advisor on the conservation, enhancement, enjoyment, understanding and sustainable use of Scotland's natural heritage.
- Biodiversity was a term first coined at the United Nations Convention on Biological Diversity, held in Rio de Janeiro in 1992, and encompasses all the wildlife and habitats in our ecosystem. The UK Biodiversity Action Plan, which was published in 1994, is Britain's response to the convention and sets out an attainable goal for biodiversity conservation.