Grech & Marsh (2008) used expert opinion and a Delphi technique to identify and rank five human factors with the potential to adversely affect dugongs and their sea grass habitats: netting, Indigenous hunting, trawling, vessel traffic, and poor-quality terrestrial runoff. Grech & Marsh (2008) then quantified and compared the distribution of these factors with a spatially explicit model of dugong distribution. It was estimated that approximately 96 per cent of habitat of high conservation value for dugongs in the GBRWHA is at low risk from human activities. Using a sensitivity analysis, it was found that to decrease risk, commercial netting or indigenous hunting had to be reduced in remote areas and the effects of vessel traffic, terrestrial runoff, and commercial netting had to be reduced in urban areas. This approach enabled Grech & Marsh (2008) to compare and rank risks so as to identify the most severe risks and locate specific sites that require further management attention.

Grech & Marsh (2008) reported that this spatial risk-assessment approach identified areas of high and medium conservation value that would benefit from additional management intervention because the current level of risk to dugongs is high. These areas included the coastal waters between Port Stewart and Friendly Point in the remote Cape York region (Fig. 2).

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Citation and/or URL

Grech, A and Marsh, H., 2008, Rapid assessment of risks to a mobile marine mammal in an ecosystem-scale marine protected area,  Conservation Biology 22(3): 711-720.   

Spatial Coverage

Great Barrier Reef World Heritage Area 

Temporal Coverage

1986 - 2005

Update Frequency

Other Information

Grech, A. & Marsh, H. (2007). Prioritising areas for dugong conservation in a marine protected area using a spatially explicit population model. Applied GIS 3(2): 1-14.

Dobbs, K., Fernandes, L., Slegers, S., Jago, B., Thompson , L., Hall, J., Day, J., Cameron, D., Tanzer, J., Macdonald, F., Marsh, H. and Coles, R. (2007).  Incorporating dugong habitats into the marine protected area design for the Great Barrier Reef Marine Park, Queensland, Australia.  Oceans and Coastal Management 51: 368-375

Grech, A., Marsh, H. & Coles, R (2008). A spatial assessment of the risk to a mobile marine mammal from bycatch.  Aquatic Conservation:  Marine and Freshwater Ecosystems 2008.