Ostrea edulis

Ostrea edulis (Linnaeus, 1758) is the scientific name of Flat oyster, formerly also named Ostrea taurica (Krynicki 1837); Ostrea adriatica (Lam. - Middendorff, 1848).

It is the European indigenous species, whose breeding was already known Roman which would have imported it into France. For the years 2000 - 2005, one produces of them in France approximately 2.000 t/an for a value of 10 M€ One formerly cultivated it starting from young oysters fished in the nature which one fattened on parks judiciously placed.

Breeding

At the 19th century, processes of collecting were developed, but overexploitation by fishing with foot because a strong regression of the species which entirely disappeared on most of the Littoral. Moreover conditions of breedings and perhaps a certain loss of Biodiversity as well as the introduction of germs or parasites by intercontinental transport caused dramatic epizooty S (1920, 1970,1980) and the bankruptcy of many producers. It is possible that pollution also weakened the individuals vis-a-vis their parasites.

A program including a knowledge zootechnical and Génétique S of the species aims at restoring this activity starting from seed oysters collected in Brittany (Bay of Quiberon). The oysters are then laid out out of deep water 2 to 3 years then sold.

Since 1989, with financing State-Area, in France, the Ifremer produces triploid oysters, genetically modified by addition of a chemical substance after fecundation so that they grow with triplets of Chromosome S instead of the traditional double helix of DNA (thirty chromosomes instead of 20). This wants to make it possible to produce sterile oysters and more sweetened and with very accéléréée growth because not losing energies to produce Gamète S. They are moreover easily marketable all the year.

Vulnerability

Like the mould S savages and much more than they, the flat oysters need to be protected from surpêche and pollution. They need a water rich in nutrients, but sufficiently clean and oxygenated. Among the new risk factors, the problem of the deposits of immersed ammunition (ex: Quiberon, Cancale) worries the experts, because the shells contain many pollutants which can affect oysters and the food Pyramide.

With the Climate warming, the concurrent or parasitic introduced species could still affect this species whereas it is far from to have found its normal populations.

External bonds

Affssa Opinion carrying in particular on triploid oyster

External references

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