Gangetic Dolphins | 23 May 2025

Source: BS 

Why in News? 

A recent study by the Wildlife Institute of India (WII) has highlighted severe chemical pollution risks posing threats to the endangered Gangetic dolphins (Platanista gangetica). 

What are the Key Facts Related to Gangetic Dolphins? 

• About: The Ganga River Dolphin, also known as the “Tiger of the Ganges,” was officially discovered in 1801.  
  • It is India’s National Aquatic Animal (declared in 2009) and State Aquatic Animal of Assam. 
  • It acts as a reliable indicator of river ecosystem health, highlighting biodiversity and water quality. 
• Habitat:  Historically found in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems across India, Nepal, and Bangladesh. But the species is extinct from most of its early distribution ranges. 

• Features: Exclusively a freshwater species, they are functionally blind and rely on ultrasonic echolocation to locate prey. 
  • Generally solitary or in small groups, often seen as mother-calf pairs.  
  • It is locally called 'Susu' due to the sound it makes while exhaling. 
• Population: There are 6,327 river dolphins in India, according to the first nationwide survey under Project Dolphin (2020). 
  • The population of Ganges dolphins  has declined by over 50% since 1957, with a 25% shrinkage in range.  
• Threat: A WII study has found high levels of harmful Endocrine-Disrupting Chemicals (EDCs) in fish consumed by Gangetic dolphins. 
  • Pollutants such as industrial chemicals (DEHP, DnBP), banned pesticides (DDT, Lindane), and heavy metals (arsenic, mercury, cadmium), mainly from agricultural runoff, untreated industrial effluents, vehicular emissions, and poor waste management, damage hormonal and reproductive systems.  
  • Additional threats include fishing gear entanglement, poaching, habitat loss from dams and water extraction, and vessel noise. 
• Protection Status: 
  • IUCN: Endangered 
  • Indian Wildlife (Protection) Act 1972 : Schedule I 
  • Convention on International Trade in Endangered Species (CITES): Appendix I 
  • Convention on Migratory Species (CMS): Appendix 1