‘IRRAWADDY DOLPHIN’ is the term that has been used in scientific literature for well over a hundred years to refer to the Orcaella brevirostris species of the genus Delphinus family Delphinidae that is found, not only in the Irrawaddy (now Ayeyarwaddy) River of Myanmar, but also in eastern India, Thailand, Laos , Cambodia, Indonesia, the Philippines, and northern Australia. Dolphins are usually found in shallow waters in mangrove forests and estuarine areas of tropical and subtropical seacoasts. In addition to these marine dolphins there are freshwater dolphins inhabiting the upper reaches of rivers in Southeast Asia. The major river systems where the freshwater Irrawaddy dolphins are found are the Ayeyarwaddy River system of Myanmar, the Mekong River system serving Thailand, Laos and Cambodia, and the Mahakam River system in Indonesia. The dolphin population in the latter two are under threat, having suffered range declines, over-fishing and depletion in numbers. The Mahakam Dolphins in fact have been recently included in the ‘Critically Endangered’ Category of the 2000 IUCN Red List of Threatened Species. Freshwater dolphins have been present in the Ayeyarwaddy River and its tributaries for over a thousand years. The earliest account of their presence there is to be found in an ancient Chinese chronicle, the New T’ang History (circa 800 AD) which recorded that the Pyu people (who inhabited the Ayeyarwaddy Basin between the 2ndC BC and the 9thC AD) carried on a brisk trade in ‘river pigs’. The British naturalist Anderson in 1879 identified two different species of dolphins in the Ayeyarwaddy River, namely the marine dolphin Orcaella brevirostris, which inhabits coastal waters and estuaries, and the freshwater dolphin Orcaella fluminalis that is found in waterways far inland. He made this distinction on the basis of morphological differences between the two putative species, but these have not been confirmed by others.

In 1998 Smith and Dobbs conducted a continuous visual survey for dolphins in the upper reaches of the Ayeyarwaddy River between Bhamo and Myitkyina from January 30 to February 6. Helping them were eight nature tourists who formed a volunteer squad participating in the survey. The team recorded 14 sightings for a best estimate of 59 dolphins present in the survey area (Smith and Dobbs, 2002). On the basis of these results the authors concluded that there was a sufficiently large population of freshwater dolphins left in the Ayeyarwaddy to make early conservation work pay off. Another finding was that regarding habitat preferences of the Irrawaddy dolphins. Like others of the same genus in neighbouring countries, viz. the Yangtse River dolphin Lipotes vexillifer, the Ganges River dolphin Platanista gangetica and the Indus River dolphin Platanista gangetic minor, the Irrawaddy dolphin were found to have a partiality for the still water of deep pools and slack or slow-moving water created by obstructions such as mid-channel islands, rocks, shoals and sandbanks and when tributaries of a waterway converge on joining it. A more ambitious survey of Myanmar dolphins conducted in November 25 to December 21, 2000 covered the entire length of the Ayeyarwaddy River from its headwaters at the confluence of the Maykha and Malikha Rivers above Myitkyina in Kachin State to Gayetgyi and Ngat Ooh islands at the mouth of the Ayeyarwaddy Delta. The results of this later survey proved depressing. In the words of Mr Brian Smith, a marine biologist associated with the Wildlife Conservation Society of New York who led the study: "The situation with the dolphins (and other aspects of the river) is much more dire than we had hoped"(personal communication). In sharp contrast to the best estimate of 59 animals sighted on a 359.6 kilometre stretch of the Ayeyarwaddy between Bhamo and Mandalay in 1998, the later survey covering the entire 1742 km length of the river yielded only nine sightings with a best total estimate of 37 dolphins, all of them being made between the Taping confluence above Bhamo and Mingun near Mandalay, a segment of only 394 miles.

These results are significant for two reasons: 1) they indicate a marked reduction in range of the Irrawaddy freshwater dolphin (of the order of some 500 km) since the late 19th century when Anderson recorded the presence of these animals downstream as far as Prome (Pyay),only 360 km from the sea, during the low-water dry season; 2) they also suggest that the freshwater dolphins in the Ayeyarwaddy constitute a discrete population whose protection and conservation thereby takes on an added urgency. Major threats to the Ayeyarwaddy dolphins are the practice of electric fishing by night and the increasing use of nylon gill nets instead of traditional throw nets to catch fish. Nylon gill nets are stretched across streams and channels from bank to bank and left in place overnight. These nets are made of fine nylon that enmesh not only adult fish and tiny fingerlings but the occasional dolphin as well. Dead dolphins found entangled in gill nets have been reported from all over Southeast Asia. An even more pervasive danger to dolphins and their habitat is the gold panning and dredging that is going on in the upper Ayeyarwaddy and its main tributary the Chindwin. These activities have been introducing ever increasing amounts of mercury into the aquatic food chain. Those most at risk from mercuric contamination are dolphins and humans, as heartbreakingly illustrated in the ecological disaster at Minimata Bay, Japan in the 1950s when hundreds of people died and thousands more suffered permanent neurological damage as a result of eating fish that had been contaminated by industrial effluents containing methylmercuric compounds. The 2000 Ayeyarwaddy survey revisited a stretch of river where several dolphins had been sighted during the 1998 survey. No dolphins were found this time; in their place were large numbers of gold mining dredges.

In order to conserve the dolphins in the Ayeyarwaddy River, Smith and Hobbs (2002) have made the following recommendations: 1) Dolphin Reserves should be set up in segments of the river where they have been found to be relatively plentiful. Gold mining would be forbidden within these reserves and the use of gill nets would be banned, the only fishing permitted being by the traditional method of using throw-nets. 2) A media campaign should be launched to raise public awareness of the dolphins as a cultural and economic resource and of the real danger of extinction facing them. Dolphins have been traditionally regarded as friendly to humans, even to the extent of rounding up large numbers of fish for them to catch, and dolphins that have been accidentally caught in throw-nets and seines (large nets with sinkers at the bottom and floats at the top), if found alive, are extricated and released. This already existing positive attitude towards dolphins should be built upon in instituting and promoting a conservation programme for the Ayeyarwaddy Dolphins; 3) The use of mercury in gold mining should be prohibited or strictly controlled. Educational materials outlining the dangers of mercuric contamination should be prepared and disseminated among the gold miners and workers. The possibility of introducing inexpensive retorts that separate the gold from the ore but prevent over 95 per cent of mercury emissions should be explored. These have been devised and are already in use in gold mining in the Amazon Basin. 4) Research should be carried out on possible genetic variation among marine and freshwater Irrawaddy dolphins. Determined and effective implementation of conservation measures are urgently needed to save the Myanmar freshwater dolphins and their natural environment. Time is fast running out for the dolphins of the Ayeyarwaddy. In the light of the situation as it stands at present they already merit inclusion in the ‘Critically Endangered’ category of the ICUN Red List. The writer would like to express his thanks to Mr Brian Smith and his co-author for permission to use the information presented in their article, Smith, B.D.,& L.Hobbs, 2000, Status of Irrawaddy Dolphins Orcaella brevirostris in the Upper Reaches of the Ayeyarwaddy River, Myanmar, Raffles Bull. Zool., Supplement 10:67-73, to Mr Steve Leatherwood for permission to print the photographs taken by him of Irrawaddy Dolphins, and to the Wildlife Conservation Society of New York, Myanmar Programme for their invaluable help in locating background reference material.