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  news.com.au 12 May 07
Holy cow
John Lambert, Courier Mail

THE light aircraft revved and then shuddered violently as it banked steeply to the left.

"Do you see anything now?" the pilot asked. "No, nothing yet," replied the passenger. "I can see some feeding trails though, so the main herd can't be far away. They may've travelled north overnight."

The plane levelled out and altered course while the passenger scribbled notes and kept a keen eye on the tumbling numbers of the GPS navigator.

If and when they located the herd, the numbers would be their only means of finding them again tomorrow. And there weren't that many left to find.

Away to the west, smoke was belching from the heavy industry that clung to the shoreline like barnacles. A broad river snaked its way inland from the bay and further upstream, the city of Brisbane reached for the sky and then stretched and yawned as far as the eye could see.

It was early morning, the tide was high, and Dr Janet Lanyon was looking for dugongs.

Somewhere below, in the waters of Moreton Bay, is a population of dugongs numbering around 850.

They are the only population living on the doorstep of a major city, and are listed as "vulnerable to extinction". While many people are unaware of their presence, almost as many wouldn't know a dugong if they met one.

IF YOU WERE TO AMPUTATE THE TRUNK FROM AN elephant, punch it squarely in the nose, lose the ears, legs and tail and add a pair of flippers, a dolphin tail-fluke and cover it all with coarse bristles, you'd have a dugong.

It forages at high tide on seagrass banks, belches and farts loudly and yet communicates with high, birdlike chirps similar to those of a canary. One researcher, albeit fondly, described it as having fallen from the ugly tree and struck every branch on the way down.

Dugongs have been a hard commodity to market for conservation. They don't have the size and mystique of a whale, wear the beguiling smile of a dolphin or fling themselves exuberantly from the depths for an adoring public.

They have never had it easy, certainly not today.

In recent years, more than 80 per cent of dugong fatalities in which the cause of death has been determined have been attributed to human impact.

When you consider that a female is not sexually mature until around 15 years old and will then only reproduce every five to seven years, it becomes clear this is an animal that requires great understanding and careful management if the species is to survive.

Lanyon, a marine scientist with the University of Queensland who is leading the world's first ongoing "mark-recapture" program within a population in the wild, has witnessed firsthand the challenges the dugongs are facing.

Her research reveals that the Moreton Bay population can sustain only a small number of mortalities per year. And while she and her colleagues play a desperate game of "research catch-up", some scientists fear the population may be gone within 25 years.

Around 500 dugongs now carry titanium tags from the university's Dugong Team. Some also carry the scars of boat strikes, shark attacks, even failed attempts at spearing.

More alarming is the discovery of lethal chemicals that may be bio-accumulating within the dugongs themselves. Dangerous PCBs (polychlorinated biphenyls) and dioxins, collectively known as POPs (persistent organic pollutants), have been detected and the race is on to determine their levels and origin. Through a process of bio-magnification, they can pass from the seagrass to the dugongs, into a female's milk and on to her calves.

These toxins were recognised by the United Nations Environment Program in 1995 as the "Dirty Dozen", to be reduced as a matter of extreme urgency.

"One of the greatest concerns is the possible effects of pollution on death and disease in dugongs, particularly since Moreton Bay is such a rapidly growing urban area," says Lanyon, 48.

"Dugongs are probably bio-indicators of healthy waterways and therefore changes in disease occurring in wild dugongs may be used as an early warning indicator of changes in waterway health."

A project now under consideration may see Lanyon teaming with veterinary pathologists to investigate the incidence and prevalence of disease within the dugong population. The project would establish baseline health data for wild dugongs and monitor the emergence of infectious diseases.

At least one necropsy on a deceased dugong has detected the deadly toxoplasmosis parasite, which is present in cat excrement and is washed into the ecosystem of Moreton Bay via stormwater run-off. It causes a fatal encephalitic cyst in the brain.

Salmonella also has been detected and humans are at risk if they eat dugongs. And the local indigenous population happen to do just that.

Blood tests already have been taken from sections of the indigenous people of Stradbroke Island to determine any levels of toxicity that may be transmissible. The results are being assessed.

The people of Quandamooka consider the hunting of the dugong, which features in their stories of creation, to be one of the last tangible and spiritual links to their "sea country".

Quandamooka man Bruce Borey explains that in the Dreaming, the Great Spirit created two dugongs known as Yangon, and he gave them a voice. They laughed and played noisily together as they moved along the coast.

As they approached the entrance of Quandamooka, the Great Spirit told them to be quiet and show respect for the country they were entering. The dugongs ignored him, and were set upon and torn to pieces by Gurrigan the tiger shark.

Later, some of the remains were picked up by seagulls and dropped around the bay to form many of the smaller islands, their red soil a testimony to their origin. The bodies of the dugongs were transformed into two large islands that protect Quandamooka, Minjerribah and Moorgumpin or Stradbroke and Moreton Islands.

The Great Spirit placed people on the islands and more dugongs within the water. They were allowed to take dugongs for food, but they had to show great respect.

Today, hunting takes place during a three-month period and is supervised by three appointed "law men". The people are now working closely with researchers, passing on some of their catch to Lanyon and her colleagues for scientific testing.

IF THE DUGONGS THOUGHT LIFE WAS DIFFICULT evading Gurrigan the tiger shark from below and the people of Quandamooka from above, they were in for a rude awakening with the arrival of Europeans in Moreton Bay.

The dugongs' Caribbean cousins, manatees, had already been noted by New World explorers, whose sightings helped engender the mermaid myths common to many cultures.

Then in 1799, explorer Matthew Flinders was puzzled by a large net he'd come across on the shores of the bay. Seven days later, he sighted "a strange sea monster" and promptly fired "three musquet balls" into the animal. He determined that the curious net was no doubt used to catch this "beast".

From then on, Gurrigan would be a mere nuisance in comparison to what was to follow.

By 1850, a traditional Aboriginal subsistence fishery was taking a large-scale and irreversible turn. Dugong oil in particular was highly sought after, leading to the establishment of a devastating fishing operation. In a commercial corruption, many Aboriginal people were used in the industry for their renowned skills as "underwater trackers", picking up the foraging trails of dugongs and determining the movements of the herds.

Dr William Hobbs, the Chief Medical Officer in Brisbane in the 1850s, administered dugong oil with astounding results. It was especially effective in treating stomach disorders and tuberculosis.

By 1858, he was using a 20-tonne cutter-boat with two whaleboats for harvesting. The boats could hold 70 barrels of oil and could remain at sea for up to three months.

The dugong population was soon decimated. Nothing from the catch was wasted.

Fat by-products were made into soap, dugong bacon and beef were sold. Tusks were used in knife handles and plates, bones crushed and used as charcoal in refining sugar. The head was boiled to a potted brawn, the tail flukes and flippers made into soup.

Dugong oil won prestigious awards at the London and Paris Expos of the late 1800s, and a 44-gallon (200-litre) drum of the precious elixir was donated to the American Centennial in 1876.

It was a time of colonial expansionism, and the land and sea and all their inhabitants were seen as business opportunities not to be wasted.

But even then the community and the government were becoming alarmed at the rapid decline in dugong numbers. Witnesses had described herds stretching a kilometre wide and 2-3km long, and suddenly the animals were scattered and scarce throughout the bay.

Community conscience began to find a voice in the local newspapers. "The parent will follow the boat to which her offspring is lashed to the shore, and make no attempt whatever to avoid the fate that soon befalls her," said a report in the Moreton Bay Courier of October 16, 1869.

"Her moans under these circumstances are so human-like, and the tenderness and appealing look in her eyes and whole countenance is so touching, that the fisherman has need to steel his heart against all sentiment, who does not almost condemn himself as a murderer. Nor is this feeling of attachment confined to the parent. The young calf, in like manner, will follow the dead body of its mother, crying out with a human-like utterance. The Malays in the islands to our north are said to collect the tears of the dugong as a charm, under the belief that they will secure the affections of those they love."

The dugong fishery was closed twice for several years in the late 1800s, but the mammals did not receive official protection in Queensland until 1969, by which time a shark-net meshing program had wreaked further havoc on the population.

It's estimated that since 1960, numbers in Queensland waters have declined by 97 per cent.

Dugongs have had little time to recover. Boat strikes, in the southern bay in particular, have replaced the fishing industry as their most lethal enemy. There are no bridges to Moreton Bay's many islands, and boats are now responsible for more dugong deaths than any other single factor.

The navigation channels linking the islands have become "marine highways" and a "balloon blimp-camera" monitoring project has helped reveal the tragic extent of the problem.

Throughout the James Cook University camera survey, marine researcher Rachel Groom, 27, regularly encountered a particular female and her very young calf. Within days of her last sighting, Groom received a phone call reporting that both animals were dead. She raced to the scene to find the mother badly mutilated by a propeller. A short time later, the calf was found in a similar condition.

"It was a poignant reminder of why the study was being undertaken," she says. "The trip back to shore with both carcasses was silent we were all overwhelmed by the tragedy."

Groom's research has revealed that the vessel responsible for the deaths of the mother and calf traverses the bay 62 times each day. The "spy in the sky" has captured high-speed vessels frequently cutting corners, leaving deep keel marks across fragile seagrass beds. Next to these are the feeding trails of grazing dugongs.

If by chance one does survive the initial impact of a boat strike, it can still die from the infection caused by the toxic anti-fouling agent that is painted on the underside of most boats.

The Queensland Parks and Wildlife Service continues to monitor dugong fatalities and in many cases passes on the dead animals to UQ for further testing.

Says Lanyon: "In some years we're actually approaching critical mortality levels from boat strike alone. We know of three dugongs, including a pair, that were hit and killed within a month earlier this year. One was a big healthy adult male that we tagged four years ago. In one year there were at least nine killed through boat strike in southern Moreton Bay."

HIGH ABOVE THE BAY, LANYON IS BECOMING anxious. They've been in the air for almost an hour and have seen only a few scattered dugongs. If her team is to take to the water tomorrow, they need a fix on the main herd or they will be looking for a needle in a haystack.

As they wheel in over the seagrass banks, the pilot spots them. Gathered on a bank below is a herd of almost 200. Plumes of silt trail them as they graze voraciously.

Several hundred metres away is the dark bulk of a tiger shark. For the moment, neither party seems terribly interested in the other, although Lanyon will keep this in mind when her team enters the water. The GPS position is noted and after one final pass, the pilot turns for home.

By 6am the following day, Lanyon and six team members are motoring across the bay in a powerful inflatable boat. Helmets are being adjusted and wetsuits donned for the "dugong rodeo".

Lanyon straps a waterproof note plate to her shoulder for recording data, and the chase is on.

A dugong is separated from the main herd and corralled within the seagrass banks to stop it from reaching deeper water. As the animal breaks the surface to take a breath, the boat pulls closer and the crew launch themselves overboard to restrain it.

It is tired but not exhausted, and a foam "pool noodle"is quickly positioned under its chest to help it stay near the surface to breathe. Measurements are taken, the sex determined, a small skin biopsy for genetic fingerprinting collected and a titanium tag crimped onto the tail fluke.

The dugong is surprisingly calm, and the entire process is over in four to five minutes. A number is brightly crayoned onto its back to ensure it's not recaptured and it swims away to rejoin the herd.

The team will repeat this as many as 15 times in the next few hours before the tide recedes and the dugongs move off the banks into deeper channels.

Lanyon's research will provide an array of critical information that may lead to some respite for the dugongs.

Genetic fingerprinting, pollution and disease studies, identification of threats, and an ongoing study of behavioural patterns will together paint a picture of just what makes this elusive and enigmatic animal tick.

The project is well on the way to establishing a complex genetic family tree of the bay's dugong population, which will be compared with data from other parts of the Queensland coast in a bid to reveal migratory and mating behaviours.

In the meantime, their evolutionary clock is ticking faster than ever before.

Life is certainly not easy for the dugongs of Quandamooka. But it's hoped the research project will lead to a management strategy ensuring these strange creatures not only remain in the bay, but remain in optimum health.

Related articles on seagrasses and dugongs
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