ON THE ROAD TO EXTINCTION – THE LEGENDARY SEA-COW OR THE DUGONG

During the early part of the century, the population of the dugongs (sea–cows) in the   Gulf of Mannar and Palk Bay was in thousands. A recent aerial survey could not spot a single animal though fishermen occasionally reported seeing one.  What has happened to the dugongs of the Gulf of Mannar and Palk Bay? Where have they gone?

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When early voyagers like Columbus and Captain Cook returned from the long voyages to North America and far eastern countries they brought back interesting and incongruous stories of mermaids and sea dragons. Their murkey eyes dulled by intoxication and homesickness saw sea mermaids holding their babies to their breast. In all probability, the manatees of the coast of America and dugongs of Australia and India would have triggered the imagination of these lonely sailors. The mermaid legends are not uncommon to India.

During the early part of the century, the population of the dugongs (sea– cows) in the Gulf of Mannar and Palk Bay was in thousands. When I used to visit Keelakarai, off the coast of Ramanathapuram in Tamilnadu, during 1960s and 1970s, regular fishing was going on using large mesh gillnets to catch the dugongs. Every month 5 – 6 sea-cows were caught in the nets and butchered on the coast. Today not even one dugong is caught in the village for months.  An aerial survey carried out by Dr. Leatherwood of Marine Park, Hong Kong, could not spot a single animal though fishermen occasionally reported seeing one. What has happened to the flourishing population of dugongs of the Gulf of Mannar and Palk Bay? Where have they gone?

Dugongs or sea-cows which are known locally as ‘Aavuli’ are marine mammals which feed their young ones. They grow to about 7’, weighing about 600 kgs. They give birth to a single calf. They are found in the Gulf of Mannar, Palk Bay, the Gulf of Kutch and Andamans where there is a dense growth of sea-grass. They feed on the sea-grass species Cymodocea serrulata and Halophyla ovata. They are found from the East African Coast extending up to Japan. There is a good population of dugongs along the Australian Coast.

Fossil history shows that they are related to elephants as indicated by their teeth structure and embryology. Being herbivorous, they feed on the sea- grass found abundantly along the shallow coast. Their mouth is modified so as to suit the feeding habit. They can browse at the sea bottom uprooting the rhizomes of the sea- grass. They are voracious eaters. 20 kg of sea-grass were taken from the stomach of a dugong by the author. They are very passive animals and their massive size is the only form of defence. But for man, it is a form of attraction. There is a belief that the meat of the dugong can cure piles and stomach problems.

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The dugongs have to come to the surface of the sea once in 5 or 7 minutes to breath. Their heavy bones and haemoglobin rich blood enable them to be under water for a longer time, but this necessity has become the cause for their downfall. The dugongs were hunted with dynamites when they surfaced for breathing. Besides, they are killed in the gillnets spread over their feeding grounds. Once they are caught in the gillnets they cannot escape as the flippers and caudal fin get entangled in the net. In the early days, before the advent of the nylon nets, the gillnets were made of hemp or coir threads. Dugongs entangled in the nets could break the meshes and escape. But today gillnets are made of nylon threads which are fatal to dugongs. They are often drowned in the nets or landed alive and then killed. They were killed brutally by plugging their nostrils with wooden stubs. Dynamites are ignited by hand and thrown on the dugong as it surfaces. A slight misjudgement in timing can cause the loss of hands or life of the fishermen.

Another major reason for the depletion of the dugong population is the loss of habitat. The sea-grass meadows of the Gulf of Mannar and the Palk Bay are disturbed by hundreds of trawlers targeting the prawn species Penaeus semisulcatus found in the sea-grass meadows. The trawl nets just uproot the sea-grass beds. The repeated cyclones have also had an impact on the dugong population. It was found that many dugongs were washed ashore after the 1964 cyclone in the Palk Bay and Gulf of Mannar.

The dugongs are included in Schedule I of the Wildlife (Protection) Act, 1972. To hoodwink the law enforcing authorities, after being caught at sea the dugongs are cut into pieces in the boat and sold surreptiously. Further, the arms of the law cannot reach the far flung coastal villages which are remote and inaccessible.

The population of dugongs along the Indian coast has plummeted far below the sustainable level. Marine mammal experts feel that a sustainable population should have at least 500 animals. A recent survey of India could not spot even a single dugong in the Palk Bay and Gulf of Mannar. Dr. Helene Marsh, an expert on dugongs, studying the dugong population of the Great Barrier Reef, Australia visited Mandapam and Rameswaram in 1989 to make an in-depth study of the dugong population. But the aerial survey and survey by boat were found to be risky due to the activities of the LTTE (Liberation Tigers of Tamil Ealam) in the area.

Captive breeding is not feasible in the case   of dugongs, due to its specialized breeding habits. Though two dugongs were kept in captivity for about 12 years in the Regional Centre of Central Marine Fisheries Research Institute, Mandapam camp, no breeding activities were noticed. There are many aquariums in Indonesia, Singapore and Japan which have dugongs in captivity. An alternative may be to transport and transplant the dugongs from Australia to Palk Bay or Gulf of Mannar as the food habits of the dugongs of India and Australia are same. But what is the guarantee that the transplanted dugongs will be safe and not become prey to the dynamite attack?

The only silver lining about the species is that there is a good population of dugongs numbering over 10000 in the Great Barrier Reef area of Australia and the Australian Government is taking great pains to protect them. A moderately good population is located near the Madagascar Coast and along the Arabian Coast.  But the dugongs of the Indian Coast seem to be doomed in spite of declaring the Gulf of Mannar as a National Park. Here again, the Marine sanctuaries come under the Forest Department which does not have much exposure to marine wildlife. Many fishermen are not even aware that they are living in a Marine National Park. If we are serious about saving the dugong, a massive awareness programme involving the local committees, fishermen and the local bodies should be initiated. This cannot be achieved by sitting in Chennai or Ramnad. For an Indian naturalist, it is sad news to learn that one marine mammal could be deleted from the faunastic list of India.

Dr. R.S. Lal Mohan,
Chairman,
Conservation of Nature Trust,
Nagercoil, Tamilnadu

Source: Eco News, 2002, Vol.8, Issue.3.


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