Behaviour, distribution and conservation threats of Dolphin Platanista gangetica (Roxburgh, 1801) in rivers of Nepal

Nepal is a land-linked country relatively small in area. However, it is home to several rivers, and these rivers are undoubtedly beautiful additions to the mountainous nation's splendid scenic landscape. Most of Nepal's surface water drains through the three major rivers are Saptakoshi, Narayani, and Karnali. Mechi and Mahakali Rivers and their tributaries mark the international boundaries between Nepal and India. All of these originate either from the Himalayas or from the Tibet Plateau and are perennial. However, dams and other water development projects, intensive fishing, pollution, and extensive human disturbances have decreased the abundance of the Ganges River Dolphin, which is now restricted only to the Koshi and Karnali River systems and in an isolated form. The first Integrated Dolphin Census of Nepal, conducted in 2016, recorded 52 dolphins throughout the country. Of the 52 dolphins, 43 were sighted in the Mohana of Karnali and its tributaries. No dolphins have been recorded recently for the Mahakali river, and sightings in the Narayani river, are occasional. The population of the River Dolphins is declining at an alarming rate. Therefore, it is important to regularly assess the status and trends of their populations and design strategies for their conservation and sustainable use.