The oyster becames sexually mature at about 1 year, and then always as a male. After about 3 years it can change sex and reproduce as a female. Thereafter it can change sex back and forth throughout its life. When reproduction takes place, the male releases its sperm into the water, where the female sucks it in to her shell and fertilizes the eggs. At a given time, a female can contain as many as 1 million eggs. Fertilized eggs develope within the female the first 10 days. The larvae swim freely in the water a couple of weeks and thereby spread to other areas. Afterwards, the larvae fall to the bottom and land on rocks, shells or stakes. There, the oyster is known as a BROOD and is about 0,3 mm in size.
   If reproduction is to take place, salinity is important, at least 24 parts per thousand, six weeks with a water temperature of at least 15-16 °C and plenty of food for the adult oysters and larvae. In Bohuslän on the Swedish west coast, this happens only once every 5-10 years.

Oysters life cycle   
Life cycle of the oyster. Read the text above.

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Ancient food

European oyster

Giant Japanese oyster

Other specie

Royal dish

Varying catches


Extensive farming

Intensive farming

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Bo Johannesson | Martin Larsvik | Lars-Ove Loo | Helena Samuelsson