 The farmers noticed, however, the Pacific oyster outgrew the endemic species in most areas, and constantly was attaching to the rock oyster collection sticks.A few years later, Pacific oysters were the dominant species in the farms, as it grew three times faster than the rock oyster, produced a reliable and constant supply of spat, and had an already established market overseas.In 1977, the Pacific oyster was accidentally introduced to the Marlborough Sounds, and farming began there in the 1990s.