Over the past two decades, Moreton Bay’s dugong population (800-1000 individuals) has become the best studied in the world, under the direction of Dr Janet Lanyon, a marine zoologist at the University of Queensland.

Dugongs (Dugong dugon) are born with smooth pale skin but all eventually develop scars from the tusks of adult males. Because they often fight each other, male dugongs have scarring from the middle of their back down to their tails. Males also use their tusks for leverage during mating, so females become more marked around the head and neck.

In order to reduce stress for the dugongs during capture and tagging, Janet and her colleagues modified a form of rodeo-style capture developed for sea turtles. It means the animals don’t need to be pulled from the water, no nets are involved and tagging can be performed in a rapid sequence at the water’s surface.

Recently, Janet’s team has begun to investigate dugong communication. Above water, you won’t detect much noise from them. But if you put your head under water near a group of dugongs, you’re likely to hear chirping. (Credit: Darren Jew)

For the past 14 summers, Janet’s team has been carrying out a mark-and-recapture program with huge success – they’ve now tagged close to 800 different animals, including some that they’ve recaptured seven or eight times over the years. (Credit: Darren Jew)

Mostly, the dugong diet consists exclusively of seagrass, and adults can consume more than 25kg a day. Their oddly shaped face is an adaptation to their seagrass-chomping lifestyle. They have a distended, trunk-like upper lip that angles sharply downward, and is covered in very sensitive bristles that help locate and manipulate seagrass in murky habitats.

The UQ team has collected important information about how dugongs grow and mature, and their social dynamics. Significant findings include the revelation that dugongs do not appear to aggregate and travel together in stable family groups, as some other marine mammals do. (Credit: Darren Jew)

Limited surface time is a trademark of dugongs. As well as their tendency to stick to murky, or turbid, water, it’s one of the main reasons they’re so elusive – and why few Australians have ever seen one. Yet they’re the most common marine mammals in northern Australia’s coastal waters, outnumbering seals, whales and even dolphins. (Credit: Darren Jew)

Cradled in a custom-made stretcher, this large animal is carefully transported for tests by the Queensland University dugong research team: Merrick Ekins at the dugong’s head; Rob Slade at the tail. In the boat, (l to r) are Janet Lanyon, Liz Burgess and Gio Damiani (in red coat). (Credit: Darren Jew)

To make accurate population estimates and better understand the behaviour of dugongs, Janet the UQ team attached satellite units and time-depth recorders to several of the animals. (Credit: Darren Jew)