Bengaluru: In 5 years, 32 fish kill incidents in city’s lakes, says report

“We couldn’t find any investigation or action taken report in the public domain, post the fish kill (incidents) in lakes of Bengaluru, either by KSPCB or BBMP,” said Raghavendra B Pachhapur, programme manager at ActionAid Association, India.

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The secondary research carried out by ActionAid Association, India, revealed the reasons for the fish kill incidents – 51 per cent due to sewage entry, 23 per cent due to toxins and chemicals, 12 per cent due to entry of industrial effluents, 12 per cent due to performance issues in the sewage treatment plant, and 2 per cent due to pesticides and fertilisers from the adjoining agricultural lands.

The fish kill incidents were reported in Doddakallasandra Lake and Subramanyapura Lake in 2017, Puttenahalli Lake in 2018, Madiwala Lake in 2018 and 2019, Haralur Lake in 2017 and 2019, and Kothnur Lake and Yelachenahalli Lake in 2022.

“Out of 32, seven fish kill incidents occurred during the month of May and five in December. Except for the month of August, fish kill is more or less spread across all months in a calendar year,” the report said.

Based on the number of fish deaths, the report has identified Haralur, Madiwala, Bellandur and Kommaghatta lakes to be the most vulnerable to fish kill incidents.

“Three fish kill (incidents) in Haralur Lake within five years is a matter of serious concern. Sewage water seems to be a major reason, apart from industrial chemicals, for fish kills. Madiwala Lake saw two fish kills, both instances occurred due to sewage entering the lake. While Bellandur and Kommaghatta lakes placed on the outskirts of the city had two fish kills each, both the lakes received polluted water involving toxins and chemicals, apart from sewage, which is the reason for the fish kill,” the report said.

The report concluded by pointing out that fish kill incidents were preventable if the KSPCB coordinated with government departments looking into lakes and storm water drains. “We need to make conscious efforts to stop fish kill (incidents) in the lakes of Karnataka,” the report said in its conclusion.

Lakes function as ecosystems in cities and are home to many species, Pachhapur said, adding that lakes play the role of recharging ground water and help prevent floods by storing excess water during the monsoon. “Rapidly increasing populations in cities do not have enough civic facilities, such as adequate infrastructure for the disposal of waste, and see lakes as an opportunity to dump or dispose of untreated local sewage. This solid waste is ending lake ecosystems,” he said.