In polluted Punjab river, the miracle and mystery of dolphins surviving mass death
A chemical reaction inside the molasses storage tank of a sugar mill released thousands of litres of molasses into the main stem of the Beas river. Among the creatures that were affected were the Indus river dolphin.environment Updated: May 23, 2018 09:52 IST
Villagers living downstream along the Beas river from Kiri Afgana village in Punjab’s Gurdaspur district woke up on May 17 to a sight they had never seen before.
Thousands of fish of all sizes were turning dead up along the river banks. The villagers immediately took the fish and put them in buckets and tubs of water, local forest department official Karm Singh said.
The locals knew from experience that the fish could be revived if released back into water even after half an hour out of the river. They hoped that the river water that had turned a dark rusty colour overnight and stank of alcohol would flow away allowing them to return the fish to the river. They waited but the water cleared only after two days.
A chemical reaction inside the molasses storage tank of a sugar mill owned by Chadha Sugar Industries Private Limited at Kiri Afgana released thousands of litres of molasses into the main stem of the Beas late on May 16.
Among the creatures that were affected were the Indus river dolphin, one of the India’s rarest mammals. The Indus river dolphin (Platanista gangetica ssp minor) is a subspecies of the South Asian River Dolphin, which includes the Gangetic river dolphin. Both the subspecies are threatened and protected under Schedule I of India’s Wildlife Protection Act, 1972.
A WWF team and forest department officials had been tracking the precarious return of the Indus River dolphins to the Beas about a decade ago after they were believed to have become locally extinct. Their return to the Beas was reported and confirmed in 2007 but their population was less than a dozen.
A small isolated population like this is at greater risk of local extinction, according to experts.
When Gitanjali Kanwar heard the news of the leak her heart sank.
“The immediate effect was plunging pH levels, turning the water acidic and the loss of dissolved oxygen,” Kanwar, a WWF India field researcher who has studied this riverine system for close to a decade, said.
The WWF team had announced earlier in May that a healthy population of about five to eleven dolphins inhabited the stretch of the river between Pong dam in Himachal Pradesh and Harike barrage in Punjab. During the survey held between May 3 and 6, the presence of a calf suggesting a breeding population was big news.
But the ugly disaster threatened to wipe the Indus river dolphins off the face of India.
“It felt like losing a close family member,” Kanwar said recalling her first reaction to the news of the leak.
Apart from turning the stretch of water acidic, the molasses also ate up the dissolved oxygen. Like humans, fish require oxygen to live, which they absorb directly from the water using their gills. When the oxygen dries up, a fish usually comes to the surface to breathe in the air from its mouth. This works for only for a short time as it is not what fish are made for and so they suffocate and die.
The only glimmer of hope for the conservationists was that dolphins do not breathe using gills but oxygen in the atmosphere from the blowhole located on top of their heads.
The loss of dissolved oxygen in the river water didn’t cut off the dolphin’s oxygen supply but whether they survived the acidic polluted water remained a torturous mystery. A survey team of WWF and forest personnel searched in vain for two days after the leak for any signs of the dolphins and during that period they thought the endangered species was lost again.
Forest official Singh glimpsed a dolphin near Karmuwala village on the third day after a disappointing morning of spotting nothing and then mistaking a floating dead cow for a dolphin.
What Singh spotted was an adult female and a few heart-stopping moments later a calf emerged in a graceful arc from the waters. On Sunday, they found a group of three.
“All of us heaved a sigh of relief,” he recalled.
Experts are still trying to find out how the dolphins remained unscathed from the acidic water.
WWF’s Kanwar believes that when faced with the torrent of foul polluted water the dolphins scurried to find cleaner side channels of the river. Since the pollutants followed the path of the river flow the side channels were not contaminated by the molasses leak.
A large number of bigger fish that were closer to the point of contamination died but those downstream were able to escape the incoming dirty water.
“There was a large scale fish mortality. The livestock was not affected because people didn’t bring them to the river water like they usually do,” Kuldip Kumar, the chief wildlife warden of Punjab, said.
Kumar said that the dirty water flowed downstream and entered the irrigation channels that feed Rajasthan and Punjab.
The loss of fish was staggering with the most mortality believed to be of three kinds of catfish: the Malhi (Wallago attu), Singhara (Sperata seenghala), monster fish (Rita rita) and the Rohu (Labeo rohita) and Mrigal carp (Cirrhinus cirrhosus), as per preliminary reports.
Villagers buried some of the fish they tried to retrieve from the waters but most were left to rot along the banks and became food for dogs, riverine birds and other fish. District authorities issued advisories to fishermen to not sell the fish that died from the pollution but some were sold anyway in places further away like Amritsar.
“The fishermen who caught the dead fish did not keep them for their own consumption, they sold all of them to the market,” a forest department official said on the condition of anonymity.
“Why would they eat this fish when they saw how they died?” he asked.
The dolphins may have survived the initial death blow but factors like a diminished prey base, which includes catfish, could affect them and the long-term impact on the ecosystem will have to be studied.
“We are still investigating the impact on the river and species,” GS Majithia, chief engineer at the Punjab Pollution Control Board, who is leading a probe into the incident, said.
The Rs 25 lakh security posted by the sugar mill was seized and it was shut down on May 18.
The actions came too late, according to Kanwar. The pollution control board waited for a disaster to take action ignoring red flags along the way, and opportunities to take action, she said.
“They were fined, they were shut down, but the fish are dead,” Atman Singh, a local forest official who guards the Harike bird sanctuary, said.
The elderly men in his group, who also guard the bird sanctuary, nodded sagely. They seemed to have grasped something that slipped from the consideration of officials: No amount of fines and shut factories could manufacture a lost species.
“The fish are gone,” one said quietly shaking his head.
First Published: May 22, 2018 17:20 IST