Context: 

The first population estimation of riverine dolphins under ‘Project Dolphin’ revealed that India has more than 6300 dolphins.

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The 'Population Status of River Dolphin in India 2024’ report was released by the Prime Minister of India on World Wildlife Day (3rd March).

Under ‘Project Dolphin’, a comprehensive survey was conducted for the first time to estimate the population of river dolphins across eight states. 

• Eight states: Uttar Pradesh, Bihar, Jharkhand, Rajasthan, Madhya Pradesh, West Bengal, Assam and Punjab.

Conducted between 2021 and 2023, the survey covered 8,406 km long stretches of Ganga and Brahmaputra rivers along with their tributaries, and a 101 km long stretch of the Beas river. 

The survey was done by the Wildlife Institute of India, state forest departments and non-profit organisations including Aaranyak, World Wildlife Fund, Turtle Survival Alliance and Wildlife Trust of India.

Methodology: Counting dolphins is challenging as they surface only sporadically to breathe and lack unique physical markers like tigers’ stripes or elephants’ ears.

• For their survey, the researchers travelled by boat at a constant speed using acoustic hydrophones — essentially underwater microphones — that picks up sounds emitted by the dolphins. 

Key Findings of the Report

As per the report, there are a total of 6327 dolphins in India in the Ganga, Brahmaputra and Indus river systems. 

• Out of these, 6,324 are Gangetic dolphins across the Ganga and Brahmaputra river basins, and three Indus river dolphins in the Beas river basin in Punjab. 
• Out of 6324 Gangetic dolphins, 5,689 were estimated in Ganga, while 635 dolphins were estimated in Brahmaputra. 

Uttar Pradesh has the highest number of dolphins at 2,397, followed by Bihar 2,220, West Bengal 815, Assam 635, Jharkhand 162, Rajasthan and Madhya Pradesh 95, and Punjab 3.

• In UP, the highest encounter or concentration of dolphins was found in the 47-km stretch of Bhind-Pachnada in Chambal River. 

The findings suggest that dolphins thrive in areas with adequate water depth and minimal human disturbances.

Project Dolphin

• Prime Minister of India announced the ‘Project Dolphin’ in August 2020 to conserve both marine and riverine dolphins.
• The Union Ministry of Environment, Forests, and Climate Change is the nodal agency of the project.

Dolphin

Globally, there are 92 species of cetaceans, of which 43 species are dolphins.

• Cetaceans (order Cetacea) are an entirely aquatic order of mammals comprising whales, dolphins, and porpoises.

30 species of Coastal and Marine dolphins have been reported from the Indian coast. The Irrawaddy dolphin (Orcaella brevirostris) is found mostly in estuaries and brackish water lakes, and the remaining 29 species are marine species. 

To conserve the South Asian River dolphin in India, a Conservation Action Plan (CAP) was prepared for a duration of 10 years from 2010 to 2020

Ganges River Dolphin

In India, the river dolphins are represented by the South Asian river dolphin or the Gangetic dolphin (Platanista gangetica) that have two subspecies – Gangetic dolphin (P. gangetica gangetica) and the Indus river dolphin (P. gangetica minor).

The government of India declared the Gangetic dolphin as the National Aquatic Animal in 2009.

Conservation status: The Ganges river dolphin has been listed as an Endangered species on the IUCN Red List since 1996.

The Ganges River Dolphin is listed on Appendix I of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora).

In India, dolphins are protected under Schedule I of the Wildlife (Protection) Act, 1972.

• The Government has also included Gangetic river dolphin as one of the 22 critically endangered species for providing financial assistance to States under the Centrally sponsored scheme ‘Development of Wildlife habitats’.

Important habitats of Gangetic river dolphins along the Ganges river have been notified as Protected Areas, such as Vikramshila Dolphin Sanctuary, Bihar.

Distribution: The Ganges river dolphin, known for its unique features, is found in the Ganga-Brahmaputra-Meghna river system and its tributaries across India, Bangladesh, Nepal, and Bhutan.

Characteristics/Features: A long thin snout, rounded belly, stocky body and large flippers are characteristics of the Gangetic dolphin.

Females are larger than males and give birth once every two to three years to only one calf.

The calves have chocolate brown skin at birth, while the adults have grey-brown smooth, hairless skin.

Despite being blind, the Gangetic dolphin is an apex predator. They hunt by emitting ultrasonic sounds, which bounces off of fish and other prey, enabling them to “see” an image in their mind. 

Being a mammal, the Ganges river dolphin cannot breathe in water and must surface every 30-120 seconds and due to the sound it produces when breathing, the animal is popularly known as 'Susu'. 

Dolphins nurse their young with milk from the female’s mammary glands.