Australia has international responsibilities for the management of dugongs in the Great Barrier Reef Region. One of the World Heritage values of the region is that it "provides major breeding grounds for large populations of the endangered species Dugong dugon". In addition, the dugong has high biodiversity value as the only species in the Family Dugongidiae and one of only four species in the Order Sircnia, all four species of which are listed as vulnerable to extinction by the World Conservation Union. Aerial surveys for dugongs were conducted over an area of some 25,800 km2 in the inshore waters of the Great Barrier Reef Marine Park (GBRMP) between 15th November and 4th December 1995. Survey specific correction factors were used to correct for perception bias (the proportion of animals visible in the transect which are missed by observers) and to standardise for availability bias (the proportion of animals that are invisible due to water turbidity). These surveys indicate that the number of dugongs in the region has not changed significantly since the mid 1980s. However, it is important to appreciate that this is regional-scale assessment which is not capable of detecting local-scale declines unless they are very large. Threats to dugongs in this region include incidental mortality in mesh nets, traditional hunting, and habitat loss. Areas where the magnitude of these threats may be local be unsustainable include: Southern Princess Charlotte and Bathurst Bays where incidental drowning in mesh nets is the major impact and the hunting grounds of the Lockhart River and Hopevale Aboriginal communities. Dugongs are seriously threatened on the coast of the GBR region south of Cooktown and in Hervey Bay. In these regions, dugong numbers have declined precipitously since the mid 1980s. Accordingly, it is essential that dugong numbers are maintained at their current level in the Northern Great Barrier Reef and that the likelihood of local depletion is minimised.