An international report sets out a plan to protect dugongs, but it might already be too late for some island populations.
Australia is defying a worrying ocean trend as dugongs, a large, elusive, marine mammal, continue to vanish from the world’s oceans.
World expert Professor Helene Marsh told Yahoo News that Australia is the “most important” country for dugongs for three key reasons:
High genetic diversity
Vast coastline habitat
Low human population density
Looking globally, the species faces increasing threats from humans — noise, chemical and plastic pollution, habitat destruction, climate change, traditional hunting, and boat strikes — according to a new report, Global Assessment of Dugong Status and Conservation Needs, which she led for the United Nations-based Convention on the Conservation of Migratory Species (CMS).
Internationally, these slow-moving 250-400kg giants are listed as vulnerable to extinction, but populations in Japan’s Nansei Islands, New Caledonia and Eastern Africa are in a particularly dire state and listed as either critically endangered or endangered.
Professor Marsh said it was now “extremely unlikely” that populations in some East Asian regions will recover, as there is a low likelihood of migration of new individuals to replenish numbers.
“Dugongs are in critically low numbers in the coastal waters of China (Vietnam-China border to the northern border of the Fujian Province including offshore islands) and Japan (waters of the Nansei Islands)… Dugongs occurring in isolated islands, such as Palau and some islands off East Africa and Asia must also be at risk,” she added.
Where are dugongs doing best in Australia?
Professor Marsh noted populations are actually increasing in the Great Barrier Reef World Heritage Area, but there are areas of concern along the reef’s urban coast where numbers are in decline. And although the species is stable along the Gulf of Carpentaria coast of the Northern Territory and Shark Bay World Heritage Area in Western Australia, there have been significant die-offs of seagrass habitat due to marine heatwaves across the latter — roughly a quarter was destroyed between 2010 and 2011.
“I am concerned at the long-term impacts of climate change and extreme weather events on dugongs in Australia (and throughout their range) due to associated seagrass loss,” she said.
“However, the dugongs’ prospects in Australia are better than anywhere else due to the high genetic diversity of Australian dugongs, large numbers and capacity to move to new pastures after seagrass loss because of the size of their range there.”
