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India will soon get a clear picture of its freshwater cetaceans, the Ganges (Platanista gangetica) and Indus (Platanista minor) dolphins respectively, as a result of an 8,000-kilometre aquatic survey carried out by the Centre, state forest departments and the Wildlife Institute of India (WII), Union Minister of Environment, Forest and Climate Change Bhupender Yadav told Down To Earth (DTE) on October 14, 2024.
The survey will be the world’s first comprehensive assessment of dolphin populations and will be considered as a baseline, according to minister Yadav and other officials.
River dolphins are indicators of a healthy river ecosystem and are crucial for the aquatic environment. However, dwindling numbers due to a plethora of reasons have pushed them towards extinction.
The Union Ministry of Environment, Forest and Climate Change collaborated with WII to assess dolphin presence and populations in rivers. Additionally, the forest departments of Uttar Pradesh, Bihar, West Bengal, Assam, Madhya Pradesh, Rajasthan, and Punjab also contributed to this effort.
The survey aims to create a detailed conservation strategy for both river and marine dolphins, alongside year-round monitoring at key dolphin hotspots.
The Ganges river dolphin was designated as a national aquatic species in 2009 and as the state aquatic animal of Assam. Meanwhile, the Indus river dolphin is the state aquatic animal of Punjab.
Before this survey, the Monitoring Ganges and Indus River Dolphins, Associated Aquatic Fauna and Habitat field guide indicated a continuous decline in dolphin populations in India’s Ganges and Brahmaputra rivers and their tributaries. Over the past century, dolphin numbers have decreased by 50 to 60 per cent. Ongoing pollution, habitat destruction, and illegal hunting have placed these species on the verge of extinction.
The field guide highlights that reduced river flow and illegal hunting for oil have led to increased dolphin mortality, resulting in local extinction in parts of the Yamuna, as well as in the Ken, Betwa, and recently, the Barak river.
In protected areas, less than 10 per cent of the river dolphin’s entire range is safeguarded. The situation is exacerbated for Ganges and Indus dolphins as they surface only briefly, making visual observation extremely challenging.
According to the field guide, the current estimated population of Ganges river dolphins in the Ganga river basin and its tributaries is approximately 2,644, while in the Brahmaputra and its tributaries, it stands at 987. This represents a decline of at least 50-65 per cent since the 19th century.
In India, the population of Indus river dolphins is estimated to be between 6 and 8, with the majority—approximately 1,816—located in Pakistan. In India, Indus dolphins are found only in a small section of the Beas river in Punjab.
The field guide notes that river dolphins are listed in Schedule I of the Wild Life (Protection) Act of 1972. They are also included in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which lists species at the highest risk of extinction and prioritises their conservation. Additionally, they are listed in Appendix II of the CMS COP, which aims to prevent trade that is incompatible with their survival.
Moreover, the International Union for Conservation of Nature (IUCN) has classified the Indus river dolphin as ‘endangered’, citing an 80 per cent decline in its distribution area due to severe habitat fragmentation from dams and changes in water flow.
Launching Project Dolphin, it was acknowledged that regular monitoring of dolphin population trends is crucial for securing their future in the country. Given their slow reproductive rate—typically producing one calf every 2-3 years—ongoing surveillance amid natural and human-induced threats is essential.
