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. The oyster industry grew to be very prosperous: 350 to 400 people worked in the construction of sites and parks almost all year round. However, in 1973–1974, flat oysters in the Gulf of Morbihan were decimated or destroyed by parasites. They were then replaced by cultivated oysters of Japanese origin, "Crassostrea gigas").