Hunting pressure has now reduced herd numbers and it was only with the introduction of aerial surveys conducted specifically for this purpose that large herds were again located on the north-eastern Australian coast. Heinsohn et al. (1976) and Ligon (1976) both reported aggregations of considerable size. In addition, Heinsohn et al.(in press) reported the presence of 500400 dugongs along a 13 km length of coast to the north of Cooktown. Sub-groups ranged in size from individual animals to herds of more than onehundred.