Dugongs – the good news and the bad

IB_ Dugong_missionary bay1

These wonderful photographs were taken by JCU researcher Dr Isabel Beasley while observing a herd of 20 dugongs, some with newborn calves, feeding in Hinchinbrook’s Missionary Bay. The dugongs appeared while Dr Beasley and rangers from the Girringun Aboriginal Corporation were conducting an annual survey of dugong and dolphin in the sea country managed by Girringun rangers – covering some 200km of coastline.

Dr Beasley was excited by the find of such a large group which indicates the healthy condition of both seagrass and water quality in the area.

On the other side of the coin it was very concerning to learn of the four dead dugongs that washed up on the Queensland coast in a single week last month. Two were in our own area: one at Saunders Beach, another south of the city.  A third was found south of Mackay and the fourth on the Fraser coast. 

Any premature or accidental death of a dugong has serious implications. Females do not begin to breed until they are between 6 and 17 years of age, with long intervals (5 to 7 years) between births. Moreover each birth produces only one calf which then remains dependent on its mother for up to two years. When an adult female is killed that inevitably means the loss of any dependent calf as well as all potential future offspring. At Saunders Beach last month a fisherman reported finding and releasing a calf from one of his nets – this would be a lucky calf only if its mother was not the one found dead there. 

Of the four dead animals it was clear that the one at Saunders Beach had drowned following entanglement in a fishing net, but the causes of death of the other three remain unknown. Both WWF and NQCC have questioned the failure of the Dept of Environment and Heritage Protection (DEHP) to perform necropsies, while DEHP maintains that the bodies were found too late to enable this procedure to be carried out successfully.

Readers may remember that another dugong was washed up on Saunders Beach in July and, although apparently found and reported very soon after death occurred, again no necropsy was done and the cause of death was never confirmed. 

Natural disasters like Cyclone Yasi and the big south-east Queensland floods of 2011, which poured huge amounts of sediment and debris into Hervey Bay and Moreton Bay, put the dugongs under increased stress. But even when conditions are good they are, like turtles and dolphin, vulnerable to boat strike, drowning in fishing nets or ingestion of foreign matter, and it is very important that every known death is investigated. The longer we remain ignorant of causes the less we can do to prevent them.

Please spread the word to observe safe boating speeds when you are in dugong waters (which is pretty much anywhere along our coast) and to report any strandings, dead or alive, as promptly as possible: 1300 264 625 is the number to call.

Acknowledgements: Grateful thanks to Yvonne Cunningham for alerting me to the good news story and for other information; to Dr Isabel Beasley for permission to use her photographs; and to the Girringun Rangers for their hard work and watchful eyes caring for country on land and sea.IB_Dugong at Missionary Bay2



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