The Emily Bay archaeological molluscan fauna as an ensemble is almost entirely intertidal in its natural occurrence, with seven species preferring sand or mud substrates and 13 species preferring hard substrates. The only exceptions are the pelagic cephalopods Nautilus and Spirula. The gastropod species Nerita atramentosa is dominant in both numbers and by weight. The rocky intertidal platform was the focus of mollusc collecting. The four most common species derive from this zone and habitually cluster in colonies, which would have made them a preferred prey. Among the many factors that may have contributed to eventual abandonment of Norfolk Island, a scarcity of easily harvestable coastal marine resources would probably have been significant.