Gangetic Dolphin
The Gangetic dolphin, scientifically known as Platanista gangetica gangetica, is a freshwater cetacean found in the river systems of the Indian subcontinent. Recognised as the national aquatic animal of India, it holds significant ecological, cultural, and conservation importance. The species is categorised as endangered on the International Union for Conservation of Nature (IUCN) Red List and is considered an indicator of the health of freshwater ecosystems.
Taxonomy and Classification
The Gangetic dolphin belongs to the family Platanistidae and is a subspecies of the South Asian river dolphin. The other subspecies is the Indus river dolphin (Platanista gangetica minor). Once regarded as two separate species, modern studies classify them as subspecies owing to similarities in their physical and genetic characteristics.
Physical Characteristics
- Size: Adults measure between 2 and 2.6 metres in length. Females are generally larger than males.
- Weight: Typically ranges from 70 to 90 kilograms.
- Body structure: Possesses a long, slender snout with sharp teeth, a rounded body, and broad flippers.
- Eyesight: The eyes are very small and lack a crystalline lens, making the dolphin effectively blind. It navigates and hunts using echolocation.
- Colouration: The skin is generally greyish-brown with a lighter underside.
Distribution and Habitat
The Gangetic dolphin is primarily distributed in the Ganges–Brahmaputra–Meghna river system across India, Bangladesh, and Nepal. In India, it inhabits rivers such as the Ganges, Yamuna, Ghaghara, Gandak, and Kosi. In Bangladesh, it occurs in the Brahmaputra and associated distributaries. Populations also survive in connected rivers of Nepal.
Preferred habitats include deep channels, meandering stretches, and confluences where fish are abundant and water flow is moderate.
Behaviour and Diet
Gangetic dolphins are mostly solitary but can sometimes be seen in pairs or small groups. They swim slowly and surface frequently to breathe. Relying on echolocation rather than vision, they are well adapted to turbid waters.
Their diet consists primarily of:
- Freshwater fish such as carps and catfish.
- Crustaceans.
- Occasional molluscs.
They often feed by swimming on their sides, using their snouts to detect prey near the riverbed.
Reproduction
Breeding usually coincides with the monsoon season. The gestation period lasts about 8 to 9 months, after which a single calf is born, measuring around 70 to 90 centimetres. Mothers care for their calves for several months until they become capable of feeding independently.
Threats to Survival
The Gangetic dolphin faces multiple challenges to its survival:
- Habitat fragmentation due to dams, barrages, and irrigation canals.
- Pollution from industrial waste, agricultural chemicals, and untreated sewage.
- Accidental entanglement in fishing nets and competition with humans for fish stocks.
- Poaching for oil and meat in some areas.
- Disturbance from heavy boat traffic and underwater noise, which interferes with echolocation.
Conservation Efforts
Legal and institutional measures have been established to protect the Gangetic dolphin:
- Protected under Schedule I of the Wildlife (Protection) Act, 1972 in India.
- Included in Appendix I of CITES, restricting international trade.
- Declared the national aquatic animal of India in 2009.
- Conservation programmes such as Project Dolphin aim to restore and safeguard habitats.
- Sanctuaries like the Vikramshila Gangetic Dolphin Sanctuary in Bihar have been created to provide safe habitats.
- Local communities are engaged in awareness programmes and monitoring efforts.
Ecological and Cultural Significance
The Gangetic dolphin is an umbrella species, meaning its protection ensures the conservation of the wider river ecosystem. It helps maintain ecological balance by regulating fish populations and is viewed as a symbol of healthy freshwater systems.
Culturally, it is regarded as a sacred and auspicious animal in many communities along the Ganges. Its conservation represents the broader effort to safeguard South Asia’s rivers, which are crucial for biodiversity as well as human livelihoods.
The continued survival of the Gangetic dolphin depends on integrated conservation strategies that combine habitat restoration, pollution control, sustainable fishing practices, and active participation of local communities.
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