- Pacific oyster, foto fitis, sytske dijksen
Oysters
Oysters live on firm underground. In earlier days, flat oysters were very common in the Wadden Sea, the delta region and the Dutch coastal waters. They grew in the wild as well as on farming beds. However, the flat oyster has been affected by various diseases and is now a rarity. The oyster shells found on the beach are either very old or come from oyster farms. The Pacific oyster has multiplied tremendously in the North Sea region since the 1980s.
- Starting life as a man, ending as a woman
- young oysters on periwinkles, foto fitis, sytske dijksen
Oysters first develop as males and turn into females in their third or fourth year. The temperature of the sea is the determining factor, which varies from place to place. In the Netherlands, it must reach a minimum of 15 degrees centigrade. However in Spain, spawning occurs at 12-13 degrees while in Norway, 25 degrees. Oysters are sexually mature within 8 to 10 months and spawn in the northern hemisphere in July and August. A female produces up to one hundred million eggs, which are externally fertilized by Pacific oysters but internally fertilize in flat oysters. The larvae swim fifteen to thirty days in the water, after which they find a hard surface to attach themselves to (such as a cockle shell). Once fastened, they continue growing into an adult specimen.
- Starting life as a man, ending as a woman
Oysters first develop as males and turn into females in their third or fourth year. The temperature of the sea is the determining factor, which varies from place to place. In the Netherlands, it must reach a minimum of 15 degrees centigrade. However in Spain, spawning occurs at 12-13 degrees while in Norway, 25 degrees. Oysters are sexually mature within 8 to 10 months and spawn in the northern hemisphere in July and August. A female produces up to one hundred million eggs, which are externally fertilized by Pacific oysters but internally fertilize in flat oysters. The larvae swim fifteen to thirty days in the water, after which they find a hard surface to attach themselves to (such as a cockle shell). Once fastened, they continue growing into an adult specimen.
WWW
See also
Info
Copyright Ecomare
