In lieu of an abstract, here is a brief excerpt of the content:

7 Dugongs in Asia Compiled by Ellen Hines Countries and Contributors Thailand: Kanjana Adulyanukosol, Ellen M. Hines, and Sombat Poochaviranon Cambodia: Ellen M. Hines, Kanjana Adulyanukosol, Phay Somany, and Leng Sam Ath Vietnam: Nick Cox, Ellen M. Hines, Keith Symington, and Kanjana Adulyanukosol Myanmar: Tint Tun and Anouk Ilangakoon Indonesia: Hans H. de Iongh Philippines: Lemnuel V. Aragones China: Shaoyong Lu, Xia Jiang, and Xin Jing Sri Lanka: Anouk Ilangakoon India: Elrika D’souza, Vardhan Patankar, Dipani Sutaria, Bharat Jethva, and Parimal Solanki Since World War II, increased exploitation of primary resources has been the policy of many Asian countries1. Especially since the 1960s, there have been high birth rates and accelerated population growth in coastal areas . The population in Asia grows by 22.5% every ten years, with 60 to 70% of people living within 50 km of the coast. This number is expected to double in the next 25–35 years2. Rapid development coupled with a rapidly increasing human population in coastal areas has resulted in the degradation of coastal resources that were historically sustainable. Along with this intensified population growth, there has been a dramatic increase in commercial fishing3. While coastal areas are vital to the needs and livelihoods of local peoples, human activities are, in many cases, degrading these areas. In South and Southeast Asia and China, as farmland becomes less available, immigration from overcrowded provinces into an open-access artisanal fishery and an often destructive and corrupt commercial fishing industry has created an atmosphere of desperation that often places the dugong and its habitat at risk4. Here, as in other areas, as coastal resources are overexploited , there follows a decline in the condition of these coastal ecosystems and consequent impoverishment of the people who depend on coastal resources. Besides fisheries depletion, the subsequent threats as a result of this acute pressure on coastal and marine areas include air and water pollution and the loss of wetlands and other coastal areas due to increased urbanization and agricultural and aquacultural development. Any assessment of conservation issues affecting the dugong, a species with specialized foraging needs that keep it close to these shores, must consider how these requirements create unique vulnerabilities to be considered when planning their protection5. In Asia, as throughout the dugongs’ range, groups of dugongs along the coast are largely scattered around beds of seagrass (map 7.1). Where dugongs were historically more abundantly distributed, reduction in numbers and local extirpations have left smaller, more isolated groups6. The low numbers and isolation of these remnant populations expose each small group to a higher risk of extirpation, where a species becomes extinct in a specific area. The patchy distribution of seagrass meadows makes the dugong especially vulnerable to the effects of increasing habitat fragmentation7. Throughout most of Asia we have limited knowledge of dugong population numbers and distribution. Therefore the recolonizing ability and travel distances of dugongs in these regions are unknown. Asia is experiencing some of the highest global levels of resource use, population growth, and development8, which could lead to a very bleak future for Asian dugongs. There are four major threats to dugongs in this region . One is the incidental catch of dugongs in fishing nets. Both illegal fishing practices (dynamite, cyanide Dugongs in Asia 59 fishing, or push nets) and legal fishing (e.g., with small mesh seines and gillnets) can directly harm dugongs and damage seagrass beds. A related key problem is the encroachment of large commercial fishing trawlers into shallow coastal waters. These boats damage seagrass beds and catch dugongs incidentally. Development and overcrowded coastal areas are the second threat. As previously discussed, destruction of seagrass beds, pollution , and increasing numbers of boats and human use of coastal areas are depleting dugong habitat areas. The third threat, in some areas, is directed take or hunting; even in areas where hunting does not occur, dugong body parts, including meat, bones, tusks, and tears, are considered valuable and are sold as food, amulets , and medicine9. The fourth threat to dugong survival is the insufficient knowledge, both nationally and regionally, of the locations and numbers of dugongs and the species and distribution of seagrass. Without this knowledge, how can we determine how best to protect these animals? In this chapter, we discuss specific issues and strategies affecting dugongs in several of the countries in this region. A separate chapter on dugongs in Okinawa follows as one of three chapters on sirenians in developed countries. For a complete status report on dugongs globally , please...

Share