Written by: Haroon Shuaib
Posted on: March 17, 2022 | 
| 中文
Indus Blind Dolphin
When we think of dolphins, we imagine one of the most social animals that humans have disciplined for entertainment. They are notoriously talented mimics and quick learners; they demonstrate empathy, innovation, teaching skills, grief, joy and playfulness. What many don’t know is that the dolphin shows we see in Dolphinariums are actually marine dolphins, also called ‘brainiacs of the sea’. Freshwater dolphins are less showy; mostly shy and unassuming, but equally alluring. In freshwater the various varieties are: the Amazon River dolphin, Tucuxi, a smaller gray counterpart to Amazon River dolphin; Bolivian River dolphin; Ganges River dolphin; Irrawaddy dolphin; Yangtze finless porpoise; and Bhullan, the Indus River dolphin. October 24 is observed internationally as the World River Dolphin Day.
Different species of freshwater dolphins
Indus river dolphin, scientific name Platanista minor, is believed to have originated in the ancient Tethys Sea and is one of the world's rarest mammals. When the sea dried up approximately 50 million years ago, it was forced to adapt to the only remaining habitat, rivers. Today, Indus River dolphin, with a pinkish-grey skin, can only be found in the lower parts of rivers in Pakistan. Their numbers declined dramatically after construction of the irrigation system in the 1930s with numerous dams and barrages. Fragmentation of habitat means that most dolphins are confined to a 750 mile stretch of the river, and isolated with impeded migration patterns.
Occasionally a Blind Dolphin gets trapped in canals, dams, and barrages on river Indus
Interestingly, Ganges and Indus River dolphins were thought to be a single species known as the South Asian river dolphin in the 1990s. However, a later study found that dolphins found in the Indus and those in the Ganges rivers are in fact their own unique species. After 20 years of studying dolphin skulls, an international collaboration of researchers found that aside from genetic differences, these river dolphin species have different morphological features, including skull shapes and number of teeth. Indus River dolphins are called ‘living fossils’.
Indus Blind Dolphin, traditionally called the magical 'Bhullan'
Over time, the dolphins adapted to life in the muddy river and are functionally blind. They rely on echolocation, a form of natural sonar, to navigate, communicate, and hunt prey including prawns, catfish and carp. They are considered blind because they lack a lens in their eye, which would have been of no use to them in any case, because of the muddy rivers. They are side-swimming cetaceans, which is adaptive for swimming in shallow water. The Indus River dolphin is one of just two species known to lie on its side and flap its tail, a behavior called side-swimming. It allows the dolphin to move between shallow pools of water in dry season. The sonar of the Indus Dolphin is so advanced that it can sense the difference between a dead or living fish. Just like a bat, it produces sound waves that bounce off the surrounding objects and are received by the dolphin in its lower jaw. These waves provide a perfect picture of the surrounding objects, their sizes, dimension, texture, etc. The sonar makes a dolphin an efficient predator despite its inability to see.
Indus Blind Dolphin navigates the water through a sonar system
Although Indus Blind Dolphin is still in the list of endangered species, due to concerted efforts of the wild life departments of the Punjab and Sindh provinces, its population has increased to about 2,000, according to recent estimates. An adult Bhullan can weigh anywhere between 155-245 pounds and can grow up to be as long as 8 feet.
Another major threat to the dolphins includes accidental capture in fishing nets set for extended hours and often overnight. Dolphins get trapped in the nets and drown. This accidental capture of dolphins is known as bycatch. Since 2000, WWF and the Sindh Wildlife Department have also rescued 80 dolphins from irrigation canals. A technology being tried to help conserve dolphins is planting ‘pingers’ near the openings to canals. The devices make a tingling sound, inaudible to humans, but avoided by dolphins and warning them away from fishing nets.
A dolphin caught in a fishing net
Indus Blind dolphins are classed as endangered on the International Union for Conservation of Nature’s (IUCN) red list of threatened species, which says the population has fallen by more than 50 percent since 1944. According to River Dolphins Initiative of WWF, on average eight dolphins become trapped in canals every year, which are then physically translocated back to the mainstream. WWF educates fishermen and engages them in promoting ecotourism activities, particularly dolphin watches. Until hunting was banned in the 1970s, some fishing communities hunted the dolphin for food or for blubber that they mixed with oil to coat their boats.
The rescue process for a trapped blind dolphin is not easy. These marine mammals are very sensitive to loud noises and human presence, and can suffer from health problems such as high blood pressure when being evacuated. With limited funding and outdated equipment, the small rescue teams have to be creative while saving dolphins, which sometimes means investing their own resources. In 2019, WWF-Pakistan and Sindh Wildlife Department rescued a female dolphin from Dadu canal, Larkana district, and transported her via ambulance back to the river.
A rescue mission for an Indus Blind Dolphin
Locally known as Bhullan in Urdu and Sindhi languages, Indus dolphin has been known to local communities for thousands of years and is an object of fascination for them. There are many myths attached to it. According to one story popular with the fishermen, there was once a saint named 'Mungo Pir' who had his shrine on the bank of the river Indus. A woman used to bring milk for him every day. One day she refused to make him the offering. In a fit of anger, the saint pushed the woman into the river and cursed her to become a 'Bhullan' and wriggle for the rest of her life, doing 'poosh, poosh' in the water. The exhaling sound of the Indus dolphin when it surfaces symbolizes this 'poosh, poosh', a woman's cry. Mungo Pir has his shrine inside the metropolis of Karachi, as the Indus used to flow near it before changing its course two centuries ago. The coastal Makrani tribes are the disciples of Mungo Pir and have an annual festival in his memory. Some Mohannas, tribal boat people of Sindh who are mostly fishermen, refer to the Indus dolphin as a mermaid.
The Indus river dolphin is a very special species due to its unique features and its resurging population is a testimony to the ecological health of Pakistan’s river system.
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