The pacific oyster, Crassostrea gigas Thunberg, has been successfully transplanted from Japan to southern Australia. Mortality was heavy amongst those transported by ship (20 days out of water), but negligible amongst those brought in by air (4 days out of water). The rate of growth has been greater than that of native oysters. Although the spatfall has been slight and irregular at other test sites, successful spatfalls have occurred in Port Sorell for three successive seasons. From Port Sorell natural spread has taken place to the Mersey River to the west and to the Tamar River to the east.