Plastic pollution posing threat to blind dolphins: experts

During recent years, incidents of stranding of the Indus River dolphin have multiplied surprisingly in the upstream of Sukkur barrage and its suburbs. Experts believe the incidents were happening apparently due to growing plastic pollution, industrial effluents, and motorised boats’ movement in waterways. The Indus River dolphin is also referred to as the blind dolphin, which has been marked as ‘endangered’ by the International Union for the Conservation of Nature (IUCN), Red List of Threatened Species (RLTS). Talking to APP in the wake of the World Environment Day observance across globe, they said protection of such rare mammals was crucial in Pakistan as they were considered the flagship species of the Indus River, having sonar an indicator of health of the Indus River ecosystem and its associated habitat. The Wildlife Department has rescued various groups of dolphins in the past, which were stranded in the Rohri canal. There have been increasing incidents of dolphin stranding in the irrigation canals in Sukkur in the past two years, which is apparently linked to the abundant plastic pollution in the Indus downstream and growing motorised movement perils, destroying their habitat, the Wildlife official sources told APP. “Now people are shifting to cutting of trees in the forests, left around the Indus River area, by using motor-boats to shift the wood-logs to another side of the river to sell them off,” sources explained. The Indus dolphin is a sensitive mammal, which relies on its highly developed hearing and sonar to orient and navigate. However, increasing plastic pollution downstream was increasing perils for survival of the loving mammals, which were often caught in plastic waste in the past years. Another reason for their dislocation was noise of motorised boats, believe the environmentalists. During the year 2021, the Wildlife Department successfully saved 10, out of 16, stranded dolphins across the canals and channels, while during 2022, a total of 38 such incidents were reported. The officials were able to rescue 34 stranded dolphins, he said. The endangered species could experience stress during the rescue and translocation process, and movement of the vehicles around in the area, he added. Former director programmes WWF-Pakistan, Dr Ijaz, said the Indus River blind dolphins act as an indicator of river health in the basins where they live. If the dolphin population in a river is thriving, then it simply means the overall state and condition of the downstream freshwater system is also flourishing. But if that population is on the mod of disturbance or decline, then it would be a red flag for the ecosystem as a whole, he said. Plastic pollution had made an ‘alarming’ contribution to climate change, which was often overlooked, he added. According to the a report of the IUCN, most dolphins are confined to a stretch of 750 miles in the river Indus and divided into isolated populations amid six barrages. The dolphins have to adapt to life in the muddy river water and are believed since then to be functionally blind. Without eyes, the rare species rely on echolocation to communicate, navigate, and hunt prey including catfish, prawns, and carp. IUCN Country Representative Mahmood Akhtar Cheema told APP that due to construction of various barrages and hydropower projects along the mighty Indus, the downstream dolphins are currently confined to just 20 per cent of their natural habitat range. Definitely, due to an increase in their population, the developmental projects and agricultural activities could peril the mammal species, he said adding that their population would gradually be declined due to worsening water scarcity and pollution. Development of irrigation projects, barrages, and habitat fragmentation could be cited as the major reasons for the dwindling population of the species, he added. A WWF-Pakistan document reveals that PET (polyethylene terephthalate), a plastic that is widely used for packing food, soft drinks, beverages, water and juices, is not biodegradable and contaminates water sources and its ways and causes the death of river and marine life when the animals ingest it. Uzma Khan, director of biodiversity at WWF-Pakistan told APP that the Indus River blind dolphin is an endangered species of the freshwater and is only found in the Indus River system, restricted from Chashma Barrage (in Punjab) to Kotri barrage (in Sindh) in the river stretch of approximately 1300-km. She said that the dolphin population between Jinnah and Kotri Barrage is around 2,000. Meanwhile, the WWF conducted some tissue sample analysis of the species, which showed high levels of heavy metals in the tissues of the mammals. An official said, “We have also found pesticide residues in both Indus dolphin and fish samples.” The WWF has already set up a dolphin monitoring network in collaboration with local communities and a round-the-clock phone helpline has also been established, she informed. The latest survey, conducted by the WWF on dolphin census revealed there are 660 dolphins between Taunsa and Guddu stretch (approximately 354-km), Uzma Khan added. She emphasised that citizens should reduce the use of plastic to zero, and promote plastic-free practices across the riverside and coastal spots, to save the dolphins and marine life.