Complex sentence: After 1927, Locmariaquer specialized mainly in the reproduction and the half-rearing of the oysters, after growing them to half size they were shiped off to Marennes, Holland England and Spain.
Split into simpler sentences: After 1927, Locmariaquer specialized mainly in the reproduction and the half-rearing of the oysters. After growing them to half size they were shipped off to Marennes, Holland England and Spain.