Fisheries of the rivers of Southeast Asia

Abstract

The lower, potamonic parts of the Ganges–Brahmaputra, the Ayeyarwady (Irrawaddy), the Salween, the Chao Phraya and the Mekong and Lancang Rivers are among the longest and most productive rivers for inland fisheries in the world. Except for the Chao Phraya, they arise on the Tibetan Plateau. All have steep and turbulent upper courses within deep mountain valleys and flat lower courses associated with large deltaic wetlands. Much of the riparian wetlands have been converted to rice culture. They all have rich and diverse fish faunas, comprising >100 families, that are adapted to a wide range of river channel and floodplain habitats. Many species are migratory whitefishes, but more sedentary blackfishes are more important in the fisheries of some rivers. Fisheries may be commercial, artisanal or subsistence and employ a wide range of static and moving gear, some of which requires considerable investment. Most species caught are consumed. Larger fishes are sold for the table; smaller individuals are often processed into a variety of forms including dried products, fish pastes and sauces. Small, low-value fishes are also utilized for animal feed (mainly for aquaculture) sometimes after processing. There are a wide range of potential threats to the inland fishes and fisheries of Asia including dam development for hydropower and irrigation, overexploitation, pollution, land use change, mining, the introduction of invasive species, and water diversion for agriculture and other purposes. Fisheries are managed either as open access fisheries or lot fisheries which are assigned to particular groups on the basis of auctions. At present, management at local, national, basin and international levels is not meeting the needs of fish and fishery conservation and urgently needs to be reformed to better protect the fisheries in the face of mounting pressures from other users of the aquatic resource.