The Union environment ministry has launched the second round of India&rsquo;s nationwide dolphin population estimation survey, expanding its scope to include new river stretches and an additional dolphin species. The survey has begun with teams of trained researchers deploying boats, recording ecological and habitat parameters, and using advanced tools such as hydrophones for underwater acoustic monitoring.
In the first phase, the survey will cover the main stem of the Ganga from Bijnor to Ganga Sagar, along with the Indus River system. The second phase will extend to the Brahmaputra, major tributaries of the Ganga, the Sundarbans region, and parts of Odisha. Alongside the Ganges River Dolphin, the exercise will assess populations of the Indus River Dolphin and the Irrawaddy Dolphin, while also examining habitat conditions, threats and other conservation-priority aquatic species.
According to the environment ministry, the initiative aims to generate robust scientific data to support evidence-based conservation planning and policy decisions for India&rsquo;s river ecosystems under Project Dolphin.
The previous nationwide survey conducted between 2021 and 2023 estimated around 6,327 riverine dolphins across the country. These included Ganges River Dolphins across the Ganga, Yamuna, Chambal, Gandak, Ghaghara, Kosi, Mahananda and Brahmaputra river systems, as well as a small population of Indus River Dolphins in the Beas. Uttar Pradesh and Bihar recorded the highest numbers, followed by West Bengal and Assam, underscoring the Gangetic basin&rsquo;s importance for dolphin conservation.
The ongoing survey follows the same standardised methodology as the earlier exercise but includes expanded spatial coverage. For the first time, population estimation of the Irrawaddy Dolphin will be conducted in the Sundarbans and Odisha. This expansion is expected to help update species-wise population figures, assess emerging threats and improve long-term conservation planning.
The programme is being coordinated by the Wildlife Institute of India (WII), Dehradun, in collaboration with state forest departments and conservation organisations, including WWF India, Aaranyak and the Wildlife Trust of India. Capacity-building efforts are also underway, with regional training workshops being conducted for forest staff to ensure uniform data collection across districts.
Meanwhile, concerns have been raised over fairway maintenance work approved by the Standing Committee of the National Board for Wildlife in the Sultanganj&ndash;Kahalgaon stretch of National Waterways-1 in Bihar. The stretch falls within the Vikramshila Gangetic Dolphin Sanctuary, a critical habitat for the endangered Gangetic Dolphin, which is protected under Schedule I of the Wildlife (Protection) Act, 1972.
To ensure navigability, dredging may be required, posing potential risks to aquatic life. The NBWL has recommended that the Inland Waterways Authority of India submit a detailed dredging plan to the Bihar forest department before any work begins. The plan must specify route maps, dredging width, locations, methods, depth, timing and duration to allow proper environmental assessment and monitoring.

New phase to cover Ganga, Indus, Brahmaputra and coastal dolphin habitats

India Launches Second Nationwide Dolphin Survey

New phase to cover Ganga, Indus, Brahmaputra and coastal dolphin habitats

January 18, 2026 | 09:58 IST