IN CERTAIN PARTS OF THE DUGONG’S RANGE SEAGRASS BEDS HAVEN’T EVEN BEEN MAPPED.”
PROTECTING SEAGRASS BEDS OFF THE COAST OF AUSTRALIA IS THE KEY TO ENSURING THE SURVIVAL OF DUGONGS, SAYS HELENE MARSH.
Dugongs are the world’s only strictly marine, herbivorous mammals and are part of the group known as Sirenians, or sea cows, that also includes manatees.
They’re found in shallow, coastal waters from East Africa to islands off Australia’s northeast coast, such as New Caledonia and Vanuatu. Australia with a population of more than 100,000 dugongs is believed to be home to the majority of the world’s dugongs with Torres Strait between Papua New Guinea and the tip of Cape York the ‘dugong capital of the world’.
They may do well in Australia because of its wide and shallow continental shelf, which is good for promoting the growth of seagrass on which dugongs feed, but also because of the low human population density.
There are many threats to the species: they’re caught and die in gillnets and shark nets, and are also hit by boats. Dugongs are also hunted by some native communities in the Torres Strait, but while many non-indigenous Australians disapprove of this, it doesn’t deplete the population. Loss of seagrass beds is another factor, particularly on the east coast of Australia where beds are being smothered by silt that runs off the land and after extreme weather events. And while efforts to conserve seagrass beds are meeting with some success, in many parts of the dugong’s range they haven’t even been mapped. Helene Marsh is an expert in dugong ecology at James Cook University.
Dugongs can be found in coastal and inland water of the Indo-West Pacific, from East Africa to Vanuatu. This image was taken in the Red Sea.