The European flat oyster, has been part of the human diet for many centuries. High mortality episodes and overfishing decimated the populations of O.edulis in Europe through the first half of the XXth century. Then, two diseases (due to Marteilia refringens and Bonamia ostreae) spread in the early 1970s and 1980s, drastically reducing the production. Despite new management practices, and intensive repletion programmes, the production of O. edulis has remained low since that time. The recovery of European flat oyster production is seen as an important opportunity for the shellfish industry in Europe. Thus this project proposal aims to attain a clear competitive advantage for a number of SME AGs and their members for different reasons: 1st- Chance to diversify production (risk management) 2nd- High market value of the product. 3rd- Environmental positive effects of fostering aquaculture activities based on native species 4rd-Biotechnology provides tools and procedures to face the oyster industry problems that were not available until recently A total of five Shellfish Producer Associations from four different Member States and three SMEs in major oyster production countries in Europe, concerned about the above mentioned issues and being aware of recent scientific progress in selective breeding programmes for bonamiosis tolerance, decided to work together with the common general objective of facing the challenge of establishing the scientific and technical bases, procedures and standards that allow the recovery of the O. edulis production, through development of strategies to tackle the main constraint, bonamiosis . To successfully achieve this goal those European Research Centres and Universities which have mainly contributed to scientific progress on O. edulis recovery and selective breeding programmes for bonamiosis resistance, will be hired by the SM-AGs and SMEs involved in this OYSTERECOVER proposal to carry out the relevant research.