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Time running out for Ganga dolphins?
R.K. Sinha and Samir Kumar Sinha | July, 2002
The Gangetic dolphin has been declared an endangered species by the World Conservation Union (IUCN). Can we assure the Gangetic dolphin a new lease of life in Indian rivers, especially in the Ganga?
Dolphins, always beloved, have always been threatened in some way or other. Here's their story:
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| Even today, poaching of the Gangetic Dolphins is a common sight |
3rd Century BC
Ashoka the Great, the emperor of the Mauryan Empire, issued a decree not to hunt or kill 'Ganga - Puputaka', as the Gangetic dolphins were known at that time.
20th Century AD
The last dolphin in the Yamuna River near Delhi was sighted in 1967. During the 90s, fisherfolk on the Ganga in Bihar were killing about 50 dolphins yearly.
21st Century AD
The Patna High Court issued notices to the central government and state government of Bihar to take measures to protect and conserve the Gangetic dolphins in the rivers.
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| All that meat is bread winning for many |
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What next?
The Indian Government has declared the Gangetic dolphin as indicator species of Ganga water quality along the Bihar stretch. But, by and large, nothing is happening to ensure its survival.
Once populating many Indian rivers, the Gangetic dolphin or Platanista gangetica was declared an endangered species by the World Conservation Union (IUCN) in 1996. The other three freshwater dolphins across the world-Indus River Dolphin (Platanista minor), Amazon River Dolphin (Inia geoffrensis) and Yangtze River Dolphin (Lipoptes vexillifer) also have the same status. The Yangtze River Dolphin is on the verge of extinction, surviving only in captivity and semi-natural reserves. The IUCN has declared it critically endangered.
The Gangetic dolphin commonly known as Susu, is a member of the zoological order Cetacea - which includes whales, dolphins and porpoises. Though it got scientific documentation and nomenclature in 1801 from William Roxburgh, a Scottish botanist and first superintendent of the Calcutta Botanical Garden, it was also mentioned as "Khuk- abi" in Babarnama during the Mughal period, when the rural folk used to burn dolphin oil for lighting their homes. The older generation of fishermen community still regard Susu as the vahan (carrier) of the Ganga - which is their source of livelihood.
Nothing fishy about Susu
When the dolphin leaps from the glories of the Ganga, it certainly looks like a huge fish. Though resembling a fish morphologically, the Gangetic dolphin is in fact a mammal. The dolphin respires through lungs and emerges above the water surface to inhale air through a blow-hole on its melon, the head. Inhaling and exhaling produces a typical sound of "Soooooosssss", which is the basis for its vernacular names:
| Hindi |
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Sous, Susa, Sunsar, Sus, Susu, Soonse |
| Bengla |
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Susuk, Sishuk, Shishumachh, Susak |
| Sanskrit |
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Sisumar, Sunsar |
| Assamese |
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Hiho, Seho, Huh |
| Nepali |
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Suongsu, Swongsu |
It emerges from water every 20-40 seconds, but sometimes it remain underwater for 6-7 minutes. It is blind, due to the absence of lens in their eyes, but it captures prey and has a strong sense of feel through its strong echolocational powers.
When it breaks through the water surface, for fraction of seconds, the observer generally sees the dorsal fin. Shooting these dolphins in water is very tough for photographers.
One myth suggests that Gangetic dolphins are the incarnation of a royal beauty, who drowned while having a dip into the Ganga. The woman had, while bathing, suddenly spotted her father-in- law riding along the bank. Embarrassed, she tried to hide her face beneath the waves and met a watery fate.
Fewer and fewer
Once in abundant supply in the Ganga-Brahmputra-Meghna and Karnphulli river systems of India, Nepal and Bangladesh, Susu population has declined severely in several stretches of the river.
A survey conducted by Environmental Biology Laboratory of Patna University during 2000-2001 showed that 68 dolphins were present in a stretch of 60 km between the Ganga-Ghaghra confluence to Ganga-Punpun confluence in Bihar. The Vikramshila Gangetic Dolphin Sanctuary (VGDS), which has been declared by Government of Bihar as a protected river stretch of about 50 km between Sultanganj and Kahalgaon in Bihar in 1991, is home for a total of 114 dolphins in a previous survey done by the laboratory in 1999-2000. In March 2001, 85 dolphins were counted in the river Kosi between Birpur and Kursela by researchers at the laboratory.
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| The Dolphin count continues to decline |
About 400 dolphins have been reported in Brahmputra River, the other major habitat of Susu in India. It is estimated that rivers in Indian territory are homes for about 2,000 Gangetic dolphins, and about half of this population is in Bihar. From Nepalese territory only 11 dolphins could be reported from Kosi, Narayani and Karnali rivers.
As no population survey of dolphins was done prior to 1990s, an authentic comparison with earlier populations is not possible to make. But reports from people and fishermen in different areas and other sources confirm that the population has declined drastically.
Killings, still!
The dolphins are facing severe threats, mainly due to incidental and directed killing by fishermen. The thick layer of fat below its skin is valued. Fishermen extract oil from the fat and use it as attractant for catfish, mainly Eutropiichthyes vacha (Bachwa) and Clupisoma garua (Gherua). The oil, which is mixed with fish bait, is sold at a rate of Rs. 100-300 per kg. Use of dolphin oil in fishing is practised in Bihar, West Bengal and Assam. When dolphins are incidentally caught in fine nylon monofilament gill net (locally known as Current Jal), fishermen rarely rescue them. Earlier, harpooning was more common, but has fallen out of practice.
Habitat degradation due to siltation of rivers, construction of barrages and dams, together with pollution, has also affected the dolphin population. Dams and barrages create physical barriers, leading to their genetic isolation in upstream and downstream segments of the river. Being at the top of the food chain, dolphins accumulate maximum amount of toxic chemicals, especially pesticides in their bodies.
Storehouse of Toxic Chemicals
Concentration of organochlorine pesticides and Polychlorinated biphenyls (ng/g wet weight) in Gangetic dolphin from India
| Tissue |
DDTsa |
HCHsb |
CHLsc |
PCBs |
| Blubber |
41800 |
1400 |
160 |
4000 |
| Liver |
1200 |
117 |
3 |
285 |
| Milk |
4800 |
400 |
33 |
620 |
- DDTs = p,p'-DDE + p,p' DDD + p,p'-DDT + o,p'-DDE + o,p'-DDD + o,p'-DDT
- HCHs= a + b + g + d isomers
- CHLs = trans - chlordane + cis-chlordane + trans-nonachlor + cis-nonachlor + oxy- chlordane
Source : K. Senthilkumar et al, 1999, Organochlorines in Ganges river dolphins, Environ. Toxicol. Chem., 18, 7, 1511-1520
Though no specific investigations have been made determine the effects of these toxicants on the physiology of these dolphins, it can be assumed to affect reproductive physiology and other vital systems.
Does anybody love the dolphin?
Gangetic dolphins have not given priority like the terrestrial wildlife of India such as tigers and rhinos. No thorough on-going study has been made about its population, biology and behaviour and major threats and sheer negligence of this animal has led to the heavy toll of their population in Indian rivers.
The Environmental Biology Laboratory of Patna University led by R. K. Sinha (co-author of this article) steered conservation efforts in 1990 with due support from national and international bodies.
Thorough studies on population and distribution patterns were made and major threats were identified. As a part of conservation efforts, massive awareness drives were started that resulted in increased awareness about this aquatic heritage of India.
But the agony continues. Killings of dolphins are always reported, but surely the rate has gone down. Regular killings in the dolphin sanctuary area have been reported. In May this year, one dolphin was killed in the sanctuary. The Environment and Forest department, which is responsible for implementation of provisions under "Wildlife (Protection) Act, 1972" must act in a manner that gives the susu a chance to survive.
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| Trouble aplenty for the Gangetic Dolphins in Bihar |
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What can be done?
During January-April 2001, about 25-30 dolphins were killed incidently by fishermen near the Ganga and Gandak river confluence at Patna, which resulted into stern action by the Patna High Court to ensure protection and conservation of Gangetic dolphins in Bihar. Intervention of the court resulted in development of management and research plans by the environment and forestry department of Bihar. But these plans await proper implementation. In Uttar Pradesh also, three existing wildlife sanctuary in three rivers are being prioritized for dolphin conservation.
Since captive breeding is not possible in case of the Gangetic dolphin, more river stretches must be set aside for them. In fact, small protected areas cannot serve the purpose, as the dolphins migrate significantly across long distances. It is important to develop a sense of conservation among fisher folk. A ban on detrimental monofilament gill nets in the river would help in reducing incidental killings. But until such time, this playful creature from the murky depths, is headed towards doom.
R. K. Sinha is Gangetic Dolphin Expert based at Patna University. He has been awarded the "Order of Golden Ark" by His Royal Highness Prince Bernhard of The Netherlands for his work on the biodiversity of the Ganga in general and the Gangetic Dolphin in particular. Samir Kumar Sinha is an Environmental Researcher and Freelance Writer based at Patna. Picture courtesy: Dr. Gopal Sharma, Patna University.
For more reading, visit the following sites :
Gangetic dolphins: www.wdcs.org
World Conservation Union (IUCN): http://www.iucn.org/
Babarnama: http://www.amitavghosh.com/ babarnama.html, or
http://faculty.washington.edu/dwaugh/CA/texts/babur1.html
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