In response to growing market demand, the intensive farming of oysters has increased significantly in recent years. In an attempt to go one better than nature, in the 1980s scientists developed a new sterile oyster. Known as the "four seasons oyster," it could be consumed throughout the year, without the need to avoid the reproductive season (commonly identified as those months without the letter "R" in their name). When oysters are spawning, they become unpleasantly milky and flaccid.
In nature, the cell nucleus of the common Pacific oyster is diploid, meaning it has a double set of identical chromosomes. Using complex genetic manipulation techniques, involving chemical, heat or pressure shock, scientists created a sterile, triploid variety, and then a tetraploid type, more fertile than the diploids. When tetraploids and diploids reproduce, they produce sterile triploids, which keep their flavor all year round and also grow faster than regular oysters. As a result, consumers lose all sense of seasonality, and oysters in the summer become as normal as strawberries in the winter. Currently, these oysters represent 30% of total oyster sales in France.
As in other examples from the aquaculture industry, it is right to question this trend towards higher production at all costs, introducing into nature animals that grow rapidly, with no controls on the possible environmental impact.