The introduction of a genetically altered oyster to increase the growth rate and avoid the ‘seasonality' of the common shellfish has proven popular among some farmers, but the spread of disease, a diminishing quality and pressure on the traditional small producers are causing concern. In France, Europe's biggest producer and lover of oysters, the manipulated variety was thought to be responsible for killing off between 40-100% of common oysters in 2008, prompting the creation of the Natural Breton Oysters Presidium,
to be launched this weekend.
The cultivation of oysters began with the Romans and today around 95% of the oysters we eat are farmed. The good news is that many of the concerns we have for aquaculture in terms of sustainability don't apply to oysters as there is little risk of pollution, no fish is required in feeding and as filter feeders they can actually help clean the surrounding waters. The ‘gardens of the sea' where first introduced in France around the 19th century following over harvesting along the coast, and by the 1950s the French oyster industry had reached a quality level unmatched anywhere in the world.
Oysters are a perfect expression of their terroir, like wine, acquiring complex flavors distinctive to their area. Environmental factors such as salt level, water temperature, seabed composition, tide range and current strength all contribute to their unique flavor. The flavor and texture of oysters is also impacted by seasons: the harvest stops in summer months, when they reproduce, as hormonal changes slow their growth, making them small, mushy and milky.
To overcome this and guarantee consumers a year-round availability of oysters, researchers created genetically altered varieties - transforming natural oysters (diploids) into sterile triploids. These triploid oysters spend most of their energy on feeding and fattening themselves up so they can be harvested from the age of 18 months, rather than three years. As they do not reproduce, triploids are unaffected by the hormonal changes of the reproductive season and can be harvested year-round.
The Natural Breton Oysters Presidium is being launched this weekend at Slow Fish, Slow Food's event dedicated to sustainable seafood, to bring together concerned producers who continue to respect tradition and follow the oysters' natural reproductive cycles. One of the goals of the Presidium is to inform and mobilize eco-gastronomes who care about the future of oyster farming so that they support these artisans. This united front of oyster farmers, fighting to protect the biodiversity of the marine ecosystem offers a beacon of hope for preserving the authentic flavors of Breton's many oyster terroirs.
For more information on the Natural Breton Oysters Presidium