Over the 20th century, European stocks of O. edulis have been severely depleted by overfishing, leading to numerous reseeding and restocking projects, mostly based on translocations (Bromley et al. It therefore contributes to objectives defined by: the OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic, the EU Habitats Directive (Directive 92/43/EEC) and the EU Marine Strategy Framework Directive (Directive 2008/56/EC) (Pogoda 2019). Ostrea edulis and its beds (referred to here as ‘reefs’) provide many ecosystem services and functions such as substrate formation and biodiversity enhancement (Haelters & Kerckhof 2009 Todorova et al. Praised for its culinary, medicinal and ecological virtues, this oyster species is today at the core of many scientific projects or actions by governmental and non-governmental organizations for its aquaculture, restocking, restoration or reintroduction in its former range all over European coasts (Pogoda et al. In Europe, the conservation of the European flat oyster Ostrea edulis (Linnaeus 1758) populations is in the focus of ecological restoration efforts to profit from the ecosystem services of this biogenic reef-engineer species. Future research needs on sex determinism, gametogenesis, cryopreservation, nutrition, selective breeding, pathogens and disease, and the development of reliable protocols for production are highlighted. The study covers the following aspects on (i) biology of the species, (ii) stressors – including pathogens and pollutants, (iii) genetics, (iv) history of production technologies, (v) seed production in polls, (vi) seed production in ponds and (vii) seed production in hatcheries. Furthermore, it provides a detailed reflection on implications for restoration, future challenges, open questions and it identifies relevant research topics for sustainable seed supply. This review provides a summary of all available knowledge and technologies of O. edulis seed production. Several of the issues that producers still face are already subjects of research many others are still unanswered or even unaddressed. Despite the development of breeding and controlled reproduction techniques for this species since the late 1930s, seed production today is mainly based on empirical concepts.
Considering the specific requirements, related to ecological restoration, such as the absence of pathogens and the preservation of high genetic diversity, the current supply is insufficient.
In commercial aquaculture (mariculture), the production of O. edulis is still largely based on natural seed collection. Accordingly, additional and new demands for seed oysters have arisen. The conservation and active restoration of European flat oyster ( Ostrea edulis) populations are a major focus of ecological restoration efforts to take advantage of the wide-ranging ecosystem functions and services this species provides.
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