Moving a little further east, to Myanmar and Bangladesh, we now hear from another very good friend of WDCS, Brian D. Smith (Director, Asian Freshwater and Coastal Cetacean Program, Wildlife Conservation Society). Brian has been working on Irrawaddy dolphins for many years now and is as close to an authority on this species as we're going to get!
Freshwater dolphins are among the most threatened wildlife on earth and WDCS has been at the forefront of efforts to conserve these enigmatic animals. The rivers, brackish lagoons and estuaries where these dolphins live are generally subject to a much greater impact from human activities compared to marine environments. This poses a particular challenge for efforts to conserve them which is further magnified by the fact that the range of these animals is limited to emerging nations where human needs are enormous, financial support is minimal, and local expertise is still in the early stages of development. One species of grave conservation concern is the Irrawaddy dolphin Orcaella brevirostris, which is considered by the IUCN to be “vulnerable” with five geographically isolated populations that are “critically endangered.” Despite the apparent gloomy outlook, Irrawaddy dolphins have been the topic of some recent good news, thanks to the collaborative efforts of WDCS and the Wildlife Conservation Society (WCS).
In 2002, WDCS and WCS initiated a study on the distribution, abundance, and factors threatening the population of Irrawaddy dolphins in the Ayeyarwady River of Myanmar. This study indicated that the population is restricted to about 400 km of channel length in the far upstream reaches of the river and that it numbers only about 60-70 individuals. It also found that the population was under immediate threat of extinction from electrocution and prey depletion due to the illegal use of electricity to catch fish. An additional study was carried out on a cooperative fishery practiced between the dolphins and cast-net fishermen where the animals voluntarily herd schools of fish toward the fishing boats and awaiting nets. Based on the results of these studies, in December 2005 the Department of Fisheries (DoF), Myanmar, established a protected area for the dolphins and cooperative cast-net fishermen in a 74-km river segment just upstream of the city of Mandalay. Since establishing the protected area an ambitious conservation program has been conducted that includes components to significantly reduce or eliminate electric fishing, promote the sustainability of the human-dolphin cooperative cast-net fishery, protect aquatic habitat and sustainable fisheries, develop a core dolphin conservation team, and monitor the status of dolphins. Frequent patrols in the protected area indicate that electric fishing has been dramatically reduced and a range-wide survey of the population in January 2010 suggests that the number of animals has stabilized or it may have even increased. Although the program is currently run by WCS and the DoF, this conservation success would not have been possible without the early, pro-active support of WDCS.
Although the major emphasis of WDCS’s work with Irrawaddy dolphins has been on populations that are at immediate risk of extinction, not only in the Ayeyarwady River but also in Songkla Lake (Thailand), Chilika Lagoon (India), the Mahakam River, (Indonesia), and the Mekong River (Cambodia and Lao PDR), it has also collaborated with WCS on a study in Bangladesh that discovered the world’s largest population of the species by more than an order of magnitude. Using rigorous scientific techniques, local and international scientists estimated that nearly 6,000 Irrawaddy dolphins live in freshwater regions of Bangladesh’s Sundarbans mangrove forest and adjacent waters of the Bay of Bengal. Despite the good news, the same study found that the dolphins are increasingly threatened by accidental entanglement in fishing nets, declining freshwater supplies, caused by upstream water diversion in India, and sea-level rise due to global climate change. The Ganges River dolphin, Platanista gangetica, an “endangered” species with a range that overlaps with Irrawaddy dolphins in the Sundarbans mangrove forest, faces similar conservation threats. Efforts are currently underway to establish a protected area network in “hotspot” channel segments of the Sundarbans where both species occur in particularly high densities.
Urgent conservation attention is needed to arrest declines in the populations of all freshwater dolphin species, and the recent likely extinction of the Yangtze River dolphin or baiji is a potent reminder of the dire cost of inaction. However, the lesson of WDCS-supported work in Myanmar and Bangladesh is that we can make a difference and that there still remains a great deal of hope for the future of freshwater dolphins.