BENGALURU: Bengaluru has witnessed more than 10 fish kill incidents so far since January. Most of them happened before the onset of monsoon and each lake has a different reason for fish kill. However, one of the main reasons is the entry of sewage into the lakes.
Activists and experts want the custodians of city’s lakes to monitor them regularly, conduct water quality tests and not shed their responsibility after rejuvenation work is done. “The order passed in 2012 by Justice NK Patil is not being followed by the lake authorities. The order explains how lakes should be maintained. We need to move from converting lakes into fish tanks and look at how we can maintain them after their rejuvenation by spending crores of rupees,” Ram Prasad, lake activist, told TNIE.
Experts said one of the major reasons for fish kill is the permission given by the state government to rear fish when the quality of lake water is bad. “Just because the quality of water falls in the D category by just a margin does not make it good for rearing fish,” said Raghavendra Pacchupar, an activist.
He said, “Karnataka State Pollution Control Board (KSPCB) should stop providing water quality data in DBU (Designated Best Use) method. Classifying lake water quality in terms of A, B, C, D and E has not been useful in preventing pollution.”
Holding officials of the Department of Fisheries responsible for not raising adequate awareness among farmers, Prasad said,”It is their duty to identify the exact cause of fish kill and see how it can be prevented.”
He said although fish kill during monsoon is normal and farmers are aware of it, not acting against it is a cause for concern.
A report by ActionAid stated that from 2017 to 2022, at least 32 fish kill incidents have been reported in Bengaluru. Entry of biomaterial waste, increase in coliform value, inlets not being cleaned before the onset of monsoon and stormwater drains becoming regular drains were some of the reasons for fish kill.
Shivakumar Magada, limnologist, College of Fisheries, said, “Steps such as stopping water from entering lakes from unknown sources can be taken to prevent fish kill. Lake inlets should always be kept clean.”
‘Need long-term solution’
Experts said changing water, applying lime, using potassium permanganate (KMnO4) and subsequent rain can reduce fish kill in lakes. However, these steps need to be on a mass scale which is not economically feasible in urban areas and needs a long-term solution.