France FOREVER – Flat Oyster REcoVERy in France

In France, the flat oyster was once a dominant species in most coastal ecosystems but is now confined to only a few localized sites, notably in Brittany. Moreover, these residual populations are subjected to growing threats that limit them still further, to the point that if no action is taken soon, the species and its habitats could completely disappear from these coasts. In that context, FOREVER, for Flat Oyster REcoVERy, was a three-year project (2018-2020, FEAMP Aquaculture Innovation call) to promote the reestablishment of flat oysters in Brittany. This multi-partner project was led by CRC Bretagne and involved CRC Bretagne Nord, IFREMER and ESITC Caen. The project has consisted in 3 complementary actions.

The first action aimed to inventory the main populations of wild flat oyster in Brittany and to describe their health and genetic characteristics.
The second action focused on the ecology and the dynamics of the two remarkable beds still remaining in the bays of Brest and Quiberon.
The last action has promoted restoration and management measures for these beds in partnership with local actors (fisheries and shellfish farming bodies, regional authorities, environmental management organizations such as Natura 2000).

One major goal of this last action was to develop dedicated settlement structures made of calcareous concrete (e.g. shellfish by-products) that are suited to flat oyster recruitment and growth, easy to use, and on which colonization can be easily evaluated.

First artificial reefs (calcareous concrete) for flat oysters in France (Bay of Brest). Photo: S. Pouvreau/Ifremer

This pioneering project in France showed that it was possible to restore the species in a significant way by developing specific methods adapted to the environments where the species is still present. It echoed other restoration projects elsewhere among our European partners in the framework of the NORA Alliance. The final report of the FOREVER project has been available since 2021 and a new project, REEFOREST, has taken over in 2022.