Riverine health and the future of dolphins in northeastern India

Abstract

The Gangetic Dolphin (Platanista gangetica) was once found in tens of thousands in the rivers of the Indian sub-continent, but the numbers have now dwindled abysmally throughout its geographical distribution. In northeastern India too, dolphins were seen in all the major rivers and also in certain wetlands during monsoon months till the early 1980s. However, the sighting of dolphins is rare now due to natural and human-induced factors. Three factors - adequate water cover, water quality, and abundance of prey food either individually or in combination- relate to River Dolphins’ existence. Variability of meteorological parameters also severely impacts on the limno-biological parameters of riverine habitats. Restoration of Gangetic Dolphins in their traditional habitats can boost ecotourism in the region. An extensive study is necessary to assess the cumulative impact of the proposed hydroelectric projects on the aquatic biodiversity of the entire eastern Himalayan region. The need of the hour is to adopt a holistic and participatory approach for maintaining riverine health and the prey base of the Barak and the Brahmaputra systems.