Marsh et al., 2004:

"The globally significant dugong population of Torres Strait supports an important Indigenous fishery for meat and oil. The fishery is protected by the Torres Strait Treaty between Australia and Papua New Guinea. A time series of aerial survey estimates from 1987–2001 confirms that there is considerable temporal variability in the size of the dugong population in the region and adds to a growing body of evidence from other aerial surveys and satellite tracking that dugongs undertake large-scale movements associated with temporal and spatial changes in the distribution of their seagrass food. The magnitude of these effects on both the size of the population and the catch cannot be disaggregated from the effects of population depletion from overharvesting.

The Potential Biological Removal method was used in conjunction with the aerial survey data to estimate sustainable anthropogenic mortality from all causes for a range of empirically-derived estimates of dugong life-history parameters. The results indicate that, although there is considerable temporal variability in the size of the dugong population in Torres Strait, it is likely that the present Indigenous harvest is an order of magnitude too high to be sustainable. Heinsohn et al. (2004) came to a similar conclusion using Population Viability Analysis."

The authors estimated that the sustainable harvest is about 190 dugongs per annum for the entire region including the Papua New Guinea communities, the Protected Zone, the Inner Australian Islands and the Northern Cape York Peninsula Area based on the 1996 abundance estimate. The corresponding figure based on the 2001 population estimate is 80-90 dugongs, an estimate similar to that independently estimated by Heinsohn et al. (2004) using Population Viability Analysis.

The authors identified the urgent need for co-management arrangements for Indigenous hunting, if Australia is to honour its international commitments to conserve dugongs and dugong hunting cultures."

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Citation and/or URL

Marsh, H., Lawler, I.R., Kwan, D., Delean, S. Pollock, K. and Alldredge, M. (2004).  Aerial surveys and the potential biological removal technique indicate that the Torres Strait dugong fishery is unsustainable. Animal Conservation 7, 435-443.

Spatial Coverage

Torres Strait

Temporal Coverage

1987 - 2001 

Update Frequency

 Not applicable 

Other Information

Heinsohn, R., Lacy, R.C., Lindenmayer, D.B., Marsh, H., Kwan, D. and Lawler, I.R. (2004). Unsustainable harvest of dugongs in Torres Strait and Cape York (Australia) waters: two case studies using population viability analysis. Animal Conservation 7, 417-425.   

See also PVA modelling for dugong harvest in Cape York and Torres Strait