Living in the doomed waters: the story of our little-known Irrawaddy dolphins
Despite becoming gradually extinct, 80 percent of the world’s Irrawaddy dolphins still call Bangladesh home. But none of its threats are assessed or addressed scientifically. These dolphins are dying out
Our boat was sailing in the shallows of south-central Bangladesh. Under the bright, baking midday sun, we were constructing an inventory and surveying fishing boats. But the level of frustration was high.
We noticed little diversity among pelagic fishes; not a single shark or ray was there. We had brought big lenses, but there were no birds to photograph either.
Leaning against the small pilothouse, I was staring at the murky, expansive, hazelnut-coloured estuary of the Bay of Bengal. I was wishing for the dolphins to show up.
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"A big fish got caught in the net. It is struggling to free itself,"— on my left, someone pointed at something in the waters. I looked in that direction.
The sun was against us, and everything appeared like a silhouette. Few long seconds passed by. And, then, I saw it—a full breaching of water, a massive splash, not any fish but a dolphin!
Within the next half-an-hour, we experienced a flurry. Everyone rushed to the starboard side, shouting, and bringing out their cameras.
The blueish-gray coloured dolphins were catching fish, carefully avoiding fishing nets. They put on a spectacular show. A young dolphin was continuously splashing its tail in a very leisurely manner.
This made things easier for us. We checked our excitement, held ourselves steady for the photoshoot. Then a pod of four dolphins came within feet from us.
They were Irrawaddy dolphins.
From the coasts to the great rivers
These short-beaked, blunt-headed, short-finned dolphins are versatile. They can sustain in euryhaline conditions ranging from coastal waters to estuaries to rivers.
These dolphins are spread across the coast of the Bay of Bengal, the Andaman Sea, and the Gulf of Thailand. Two great rivers in Southeast Asia, the Irrawaddy (from there the dolphin gets the name) and the Mekong, are also a home to them.
Apart from the Australian side, they also inhabit the shallow waters of the Indonesian archipelago. The species is present in brackish lakes. A small sound in Palawan marks their easternmost limit.
In Bangladesh, they can be mostly seen in the Sundarbans and along the southern extremities of the Ganges-Brahmaputra-Meghna confluence.
Globally endangered, unchecked threats
The International Union for the Conservation of Nature (IUCN) has declared the species endangered. The assessment considered the dwindling number of the dolphins that experienced a staggering 50 percent reduction in population in the last 10 years.
Gill netting is their biggest threat. These nets are hung vertically in the water column, drifting freely.
As a consequence, these unusually large-bodied mammals get drowned from net entanglement. Apart from gill netting, the dolphins are at the risk of getting hit by propellers of mechanised boats.
In the Mekong and the Irrawaddy, these dolphins were once used to hoard up fish for the fishermen—much like the service of a shepherd dog. With the advent of technologies, this mutual relationship had corroded away.
Such beliefs are also long lost in Bangladesh. In the past two decades, dolphins of the Asian waters were mercilessly persecuted for meat and oil.
Number of dolphin deaths in Bangladesh is experiencing an all-time high. Since 2017, about 300 deaths were noted by 'Save the Nature of Bangladesh'. The dead-bodies (belonging to multiple species) popped up all over the coasts, from Patuakhali to St Martin's Island.
Several countries take measures to protect dolphins. Gill net usages are banned in Cambodia. In Myanmar, the practice is limited in areas with bans on certain mesh sizes. We do not have any on-field measure to save the dolphins from gill nets, neither there is any official, updated tally of dolphin casualties.
Laos has three, how many we do?
Irrawaddy dolphins are functionally extinct in Laos. In a 2016 survey led by the World Wildlife Fund (WWF), only three individuals were spotted in the Laotian part of the Mekong.
On the south of the Mekong, the dolphin numbers hovers just below 100, according to a 2017 study of WWF Cambodia. In the Irrawaddy, 78 dolphins were recorded in 2018 by the Wildlife Conservation Society (WCS) Myanmar. In Palawan, the population estimate stands at 35 individuals.
Bangladesh, through publishing their extensive 2006 survey in the coastal waters and the high seas of Bangladesh in the Journal of Cetacean Research and Management in 2008, provided an astounding information —about 5,383 Irrawaddy dolphins live in the country.
A couple of years ago, another survey of WCS Bangladesh gave us the number of the species in the Sundarbans. There are 451 individuals—says the work featured by the journal Marine Mammal Science in 2006. In both cases, the numbers were estimated from statistical modelling on the basis of the systematic surveys.
It has been 15 years since the discovery. How many dolphins do we have now?
The final report of the Bangladesh Dolphin Action Plan 2020-2030, published in 2019, says that there are about 198 Irrawaddy dolphins in the Sundarbans. The number came from a survey of 1340 km of rivers within the mangrove.
30 more individuals were found in the rivers around Barguna and Patuakhali. The draft Nijhum Dwip Marine Reserve Management Plan 2019-2034 mentions about 93 Irrawaddy dolphins in the Nijhum Dwip waters.
The report also states two more statistics. WCS Bangladesh, based on the 2017-18 and the 2018-19 survey, found a total of 485 Irrawaddy dolphins.
Undoubtedly, Bangladesh holds the largest population of this species. But has the number decreased over the years? Or did the model give us an inflated number? Where did all the dolphins go?
"This discovery gives us great hope that there is a future for Irrawaddy dolphins. Bangladesh clearly serves as an important sanctuary for Irrawaddy dolphins," said Dr Brian Smith, the lead author of the 2008 study and the pioneer of dolphin research in Bangladesh stressed, to Mongabay.
The dancing dolphins left us after a while. As our boat had moved forward, the horizon became dotted with the boats, the surface appeared beaded with the floats of deployed gillnets. The waterscape transmitted a tension between life above and below. Where do the dolphins belong in this synergy?
