Information sheet 2: The status of dugongs on the Great Barrier Reef

Abstract

Dugong numbers on the urban coast of the Great Barrier Reef and the southern coast of Queensland appear to have declined significantly since the 1960s. It is too early to say whether this decline is still occurring, at what rate, or whether the population is beginning to stabilise at a much lower level than previously. However, surveys since 1986/87 indicate that numbers on the urban east coast of Queensland can fluctuate significantly, probably as a result of large-scale movements in response to seagrass dieback. In contrast, surveys since 1985 of dugong populations north of Cooktown suggest that numbers are relatively stable, although (1) there is evidence of movements between regions; (2) individual dugongs undertake movements over several hundred kilometres, (3) the human related mortality of dugongs is not sustainable in at least some years and the likelihood of local depletions should not be ignored.