The survey period was characterised by unseasonally poor weather, and opportunities to survey under suitable conditions were limited. For this reason, the survey coverage was incomplete, with the focus directed towards high quality habitats at the expense of regions where few or no dugongs have been recorded in previous surveys. This resulted in the omission of the region between Cape Bedford and Innisfail, part of the coastline south of Mackay, including Broad Sound, the coast between Hervey Bay and Moreton Bay, and three of six blocks in Moreton Bay. The results of the 1999 survey indicate that dugong numbers in both the southern GBR and Hervey Bay regions in October–December 1999 were significantly higher than thecorresponding estimate in 1994, but not significantly different from that obtained in 1986–1987. Most of the increase was in the northern part of the survey region (the Central Section of the GBR).