image: Oysters form species-rich beds and reef structures, considered as biodiversity hot spots. view more
Credit: Klaus Janke
A new European alliance for the conservation of the European flat oyster has been established.
If successful, it could see the water quality and biodiversity of the North Sea greatly improved.
The European flat oyster represents a key species with important ecological functions and ecosystem services in the marine ecosystem. As reef structures, oyster beds provide food and habitat for numerous species and, in addition, serve as nursery grounds for many fish species.
However, stocks of the European flat oyster (Ostrea edulis) are classified as highly endangered all over Europe - it is considered to be extinct in large parts of Europe and the German North Sea.
Intensive and overexploiting fishery activities across Europe led to serious decline in the mid-20th century and since then habitat loss, cold winters and diseases have prevented the regeneration of this species.
For the first time, experts from across the continent have agreed on common European restoration strategies.
University of Portsmouth Marine Biologist Dr Joanne Preston is a founder member of the new European Native Oyster Restoration Alliance (NORA). This European network aims at reinforcement and restoration of the presently rare and endangered native European flat oyster.
Dr Preston said: "The long-term goals of the alliance are to re-establish the native European flat oyster as a former key species in the North Sea and adjacent European seas as well as to extensively restore species-rich oyster reef structures. In the future, regulated fishing activities within specified areas may be possible once the goals are achieved."
Initiated by the German Federal Agency for Nature Conservation (BfN), the Native Oyster Restoration Alliance (NORA) was established during the first international workshop on oyster restoration that was recently held in Berlin. The workshop was attended by 65 experts from 10 European countries and the US. Network members are representatives of nature conservation agencies, science, non-governmental organisations (NGOs) as well as oyster farmers.
European scientists at universities, nature conservation agencies and organisations - also within the BfN - have been active in research, restoration and protection of the European flat oyster for many years. Currently, restoration projects are carried out in Great Britain, Ireland, the Netherlands and Germany.
Dr Preston is currently leading a University of Portsmouth project, in partnership with Blue Marine Foundation and MDL marinas, that aims to restore the native oyster population to the Solent, off the South Coast of England, which once supported the biggest oyster fishery in Europe.
Dr Preston added: "Oyster beds are considered to be biodiversity hot spots. By filtering large volumes of water, oysters also improve water quality on local scales. A single oyster can filter up to 200 litres of sea water per day - multiply this by millions of oysters, which historic records suggest populated the North Sea in the past, this could provide a significant eco-service which acts in a manner similar to giant biological water treatment plant."
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