Dugongs, or sea cows, believed to be the source of mermaid legends, are threatened with extinction within 40 years, and an arsenal of measures, from replacing fishing nets that trap them to setting up marine reserves, are vital for their survival, a United Nations-backed forum has warned.

"Man-made threats pose the greatest risk to the gentle sea cow," the UN Environment Programme (UNEP) said, summing up a meeting this week in Abu Dhabi, United Arab Emirates (UAE), of Governments, international and non-governmental organizations (NGOs) convened by the UN Convention on the Conservation of Migratory Species of Wild Animals (CMS) on the seemingly clumsy animal, the world's only herbivorous mammal living in marine waters.

"Illegal poaching, unsustainable hunting by local communities, severe injuries from ships and vanishing sea-grass beds are accelerating a critical loss of habitat and threatening populations," it said, stressing that enhanced regional cooperation among countries hosting dugongs is essential to ensure the survival of the creature that sailors once took for a mermaid when spotted from afar.

A newly developed toolbox to mitigate threats includes incentives to replace harmful gillnets with alternative fishing gear to reduce so-called by-catch and minimize the mortality rates. Use of gillnets has led to incidental entanglement in fishing gear. As fisheries become increasingly commercialized, by-catch will become even more frequent and serious, UNEP warned.

The second largest threat is unsustainable direct consumption which can result once a dugong is caught in the nets. In addition, dugongs are also legally hunted by local communities in some countries for traditional consumption.

"Simple innovative tools and new incentives for local fishermen have been presented to the signatories to the CMS dugong agreement, which might prevent this rare species from becoming extinct," CMS Executive Secretary Elizabeth Maruma Mrema told the gathering.

Steps include protecting breeding and feeding areas by setting up marine reserves, temporal limits on fishing, and loans to fishermen to buy new boats and use line-fishing gear.

According to an assessment undertaken in 2008, the dugong is now extinct in the Maldives, Mauritius and Taiwan, Province of China, and declining in other waters in at least a third of the areas where it is found. But current information is too limited to even assess completely the threats.

Man-made risks are exacerbated by the dugong's low reproduction rates. Even a slightly reduced survival rate of adults from habitat loss, disease, hunting or drowning in nets can trigger a dramatic decline.

Data from fishermen in 20 countries in the Pacific Islands, South Asia, and the UAE to assess the threat of fishing on the dugong's survival in parts of its migratory range will be combined into a geographical information system to identify the trouble spots, provide crucial information on existing populations and map important habitat areas such as sea-grass beds. In 2011, the survey will be extended to East Africa, the western and north-western Indian Ocean and South Asia.