The return of the flat European oyster – EURACTIV.com | Popgen Tech

European researchers are trying to revive Europe’s native oyster, which has nearly died out over the past century.

Read the original French article here.

The European flat oyster used to be everywhere: Until the middle of the 20th century, Ostrea edulis was fished, farmed and eaten from the North Sea to the Adriatic Sea, from Norway to Croatia.

Overfishing, but mostly the arrival of the two parasites Marteilia and Bonamia in the 1970s and 80s, reaching Europe through trade globalization, the populations were wiped out. Today only a handful of wild sites remain of this unique species native to the continent.

In France, a small number of oyster farms still exist, mainly in the Bay of Mont-Saint-Michel, an area slightly more protected from disease. The production of flat oysters does not exceed 1,000 tonnes per year, while hollow oysters produce around 80,000 tonnes.

The common oyster that we eat most today is a species from Japan called Crassostrea gigas, which is much hardier than its European cousin.

European Native Oyster Restoration Alliance

In 2017, a hundred or so European scientists and managers joined forces to help the flat oyster reclaim the coast, creating the Native Oyster Restoration Alliance (NORA).

Since then, projects have been set up across a dozen member states.

In France, the Comité Régional Conchylicole de Bretagne Nord (CRCBN) is preparing the return of the Ostrea edulis. After identifying the last natural beds and carrying out several biological and ecological studies on the species and its environment, the first experiments to recolonize the marine environment began in Finistere, in the west of Brittany.

They produce oyster “families” in tanks attached to artificial reefs made of biomaterial props, before being placed on wild beds at sea.

The project, called ARCHE, which is 80% funded by the European Maritime, Fisheries and Aquaculture Fund (EMFAF), was launched in 2018 and will be completed in March 2023.

“Some of the reefs have been in the water for two years, and we are satisfied, optimistic for the future,” Benoît Salaun, director of CRCBN, told EURACTIV France, adding that since it takes three years for an oyster to to grow fully, the project is not finished and experiences still need to be made.

To avoid a new wave of infection and to make large-scale farming possible again, the most parasite-resistant shellfish were pre-selected.

Nevertheless, some questions remain unanswered. Will the implant work in the open sea, despite an environment subject to various hostile elements? Will these oysters succeed in reproducing with their wild relatives and passing on their resistance?

In Belgium, the UNITED 2020 project has also started this kind of restoration, especially in the wind farms of the North Sea.

A little further north, around the Heligoland archipelago, Germany is designing an oyster hatchery for the restocking of hatchery as part of the PROCEED project (2018-2024).

Benoît Salaun emphasized the common European will to revive the flat oysters.

“We are working on improving the strains, on selection, especially with the Wegener Institute in Germany. We even go so far as to exchange families of oysters, to have more diversity.”

Hazelnut taste

Another of NORA’s goals is to restore marine habitats and the entire ecosystem. The oyster is an ‘engineering species’ that creates natural reefs that attract rich biodiversity and capture carbon. It also filters water, allowing algae to better absorb light.

For professionals, the development of the flat oyster will open up the market and reduce the health risks associated with monocultures.

Although France is the main producer and consumer of flat oysters, some other member states promote their own farms, such as Ireland, with Galway’s flat oysters, or the Ston oysters from Croatia.

Can a lost return from Ostrea edulis expected in the following years?

“If we reach 10%, it will already be a success,” said Benoît Salaun. “But it is the consumer who will decide.”

Whether the heavily iodized taste with a hint of hazelnut will please the European palate remains to be seen. The price will also be twice as high as that of the hollow oysters, at between €10-15 per dozen.

[Edited by Nathalie Weatherald]