Panathur Lake fish kill cause yet to be ascertained

Maqsood Maniyar | NT
Bengaluru

The Fisheries Department has disclosed that the water quality report on Panathur Lake came out normal, while observers and experts have faulted this method of assessing fish kill. People with knowledge and experience in lake conservation said that the Fisheries Department should have done autopsies of the dead fish to determine the cause of death. They said the water quality report will not adequately address the issue.

The lake’s water was sent for analysis because of the fish kill that occurred this month. The Fisheries Department suspects that an herbicide that was used in the vicinity may have been washed into the lake during the rains and killed the fish.

The department, however, conceded that they couldn’t identify the active chemical in the herbicide that may have been responsible for killing the fish. A laboratory report disclosed that the PH level of the Panathur Lake was 7.3, which is well within the acceptable limit for fish culture (6.5 to 8.5). The conductivity was 0.87 milliSiemens per cm and the standard is less than 1.

The alkalinity was 120 Calcium Carbonate mg per litre and the figure should be less than 400. The hardness was 162 mg per litre, when it should be less than 500. The total dissolved solids should be 296.66 mg per litre, when it should be less than 500. The report also said: “The analyses of the lake water sample are under desirable. Hence water can be utilized for fish culture.” Friends Of Lakes Co-founder Ramprasad said that autopsies of the fish were essential in such cases.

“A comprehensive study including post-mortem of the dead fish has to be done to arrive at the conclusion, as the probability is more than just one as the cause of the kill. The Fisheries Department has to take the onus of such happenings as they don’t coordinate with other agencies for the maintenance and upkeep of the lakes in Bengaluru. The Fisheries Department should also do regular checks, tests, training, etc for an ecologically sound, environmentally friendly, biodiversity rich lake,” he said.

A retired fisheries scientist echoed these sentiments. “If they suspect such a thing, then they have to do autopsies. They have to do an analysis of the muzzle of the fish,” he said. He added that if herbicide was responsible, the chemicals would be accumulated in the muzzle of the fish.

Still suspect herbicide:

Fisheries Dept Assistant Director of Fisheries Nagendra Babu said they still suspect herbicide, but they couldn’t confirm the same through reports. “They couldn’t trace the chemical because they have to know which chemical it is that they are looking for and we couldn’t tell them. It is an expensive process as well. What they did is analyse the water quality and conclude that it was good for fisheries. I think someone had sprayed something the day before (the fish kill) to destroy weeds. Rain just washed it into the lake,” he said.