Securing a safe future for the river dolphins of Bangladesh
Though Bangladesh is rich in dolphin diversity, these astounding aquatic creatures might go extinct soon if the current scenario remains unchecked
The Ganges River Dolphin and the Irrawaddy Dolphin are two of the 10 dolphins and whales that call Bangladesh home. While the freshwater-dwelling Ganges River Dolphin is threatened with extinction, the Irrawaddy Dolphin, mostly confined to estuarine rivers, is also in trouble.
This is why the Ministry of Environment, Forest and Climate Change has adopted the Conservation Action Plan for the Ganges River Dolphin and Irrawaddy Dolphin of Bangladesh (2021–2030) and initiated a project to expand the protected areas system for the conservation of important aquatic ecosystems.
With support from the Global Environment Facility through UNDP Bangladesh, many national and international NGOs have already extended their hands to translate this plan into action.
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Dolphins are going extinct through entanglement in gillnets and deliberate killings for use as a fish attractant and hereditary medicine.
At present, the existing threats to cetaceans in Bangladesh are collision due to heavy water traffic, net entanglement, intentional killing for oil, sedimentation, reduction of freshwater flow, pollution, dam construction, salinity intrusion, etc as identified in a report of the Forest Department.
It is presumed that though Bangladesh is rich in dolphin diversity, these astounding aquatic creatures might go extinct soon if the current scenario remains unchecked.
The Ganges River Dolphin and the Irrawaddy Dolphin are acknowledged as two cornerstone species for the riverine ecosystems in the country. The former live in all of our major river systems such as the Padma, the Jamuna, the Meghna, the Sangu-Karnaphuli and the northern rivers of the Sundarbans.
The Irrawaddy dolphins are somewhat tolerant of saline waters; their range encompasses the southern Sundarbans waters, all coastal rivers and the mouth of the Bay of Bengal.
Why protect the dolphins?
The dolphin is a pivotal index species in the riverine ecosystems to assess the situation of biological biodiversity. It can ultimately help understanding the situation of other aquatic flora and fauna.
Dolphin presence signals good health of any river ecosystem. However, owing to our collective negligence, the Ganges River Dolphin is now locally extinct from several tributaries like the Kushiara, the Dharala, the Karatoa, etc. This happened in the last three to four decades.
The newly formulated dolphin conservation action plan points out these issues while updating knowledge on the distribution of dolphins, the significance of dolphins in the aquatic ecosystems, threats to dolphins, potential impacts of climate change on dolphins and measures to tackle these challenges.
Dolphins in the Bengal
Historically, the Ganges River Dolphin was present in the entirety of the Ganges and the Brahmaputra Rivers, and all their tributaries stretching from the Bay of Bengal estuaries to the Himalayan foothills.
On the distribution of Ganges River Dolphins across the Indian Subcontinent, an impression could be found in the Baburnama (ca. 1500 AD) where the Mughal emperor Babur remarked them as 'water-hog spread in all the Hindustani Rivers.'
The iconic French naturalist and zoologist Georges Cuvier went even further saying that the 'susu' ascended the Ganges in such a great number that these animals were limiting their navigability.
The Ganges River Dolphin was first scientifically reported in 1801. This is one of the three extant obligate freshwater dolphins. The fourth one, the Yangtze River Dolphin, is declared as functionally extinct.
Named after the Irrawaddy River (the present Ayeyarwady) of Myanmar, the Irrawaddy dolphin has many characteristics that have placed it in the family of oceanic dolphins. But its biology is not well known.
The brackish water-loving Irrawaddy Dolphin is present in coastal areas in three rivers in Southeast Asia, namely the Ayeyarwady, the Mekong and the Mahakam (Indonesian Borneo).
Interestingly, the largest population of the Irrawaddy Dolphins in the world is reported from the open estuarine waters of Bangladesh's coasts. The rivers of the Sundarbans have around 451 individuals, although how many exist along the entire Bangladesh coast is still unknown.
Our rivers, our dolphins
Bangladesh is the largest deltaic country in the world. The Bengal Basin is blessed by the Ganges, the Brahmaputra and the Meghna. The entire delta is constituted by the accumulation of sediment of the three major river systems.
In monsoon, it becomes one big wetland.
We also have a very extended hilly river system, namely the Karnaphuli-Sangu system. In addition to these, the Sundarbans and the complex coastal estuaries offer some of the best habitat to riverine dolphins.
Much more to do
Dolphins are protected under the Bangladesh Wildlife (Protection and Security) Act 2012, in adherence to the UN Convention of Biological Diversity (CBD) 1992. Bangladesh now has six wildlife sanctuaries, particularly for river dolphins in the Sundarbans and the Padma-Jamuna confluence.
But these sanctuaries altogether cover only 1,648 hectares. Such areas in our rivers need to be expanded and should have connections between them.
Section 37 of the Wildlife (Protection and Security) Act 2012 specifically mentions statutory penalties to kill or hold dolphins or dolphin-based derivatives (dolphin ivory, oils, etc) that can go up to four years of imprisonment and a fine of Tk2 lakh.
However, thus far, there has been no plan to tackle the human-dolphin negative interactions in Bangladesh.
"Dolphins are going extinct through entanglement in gillnets and deliberate killings for use as a fish attractant and hereditary medicine," according to Dr Mokhlesur Rahman of the Centre for Natural Resources (CNRS), an environment-centric organisation in Bangladesh.
The connection between humans and dolphins is also severed, often sparking unintentional retaliatory events. "It is to make people aware of the protection of dolphins as inserted in the national legislation of Bangladesh that we have already installed 10 billboards and two electronic display boards under our 'Expanding the Protected Areas System to Incorporate Important Aquatic Ecosystems (EPASIIAE) in our project areas," he added.
"We hope to create long-lasting awareness within common people about the importance of dolphins and the existing legal mechanism that addresses the issue of safeguarding of the dolphins through undertaking vast advocacy and campaign programmes under our EPASIIAE Project," observed Anisul Islam, director of CNRS.
The Conservation Action Plan for the Ganges River Dolphin and Irrawaddy Dolphin of Bangladesh has ushered in hope.
Audity Falguni works in the B4RL Project of CNRS
