Eight cases of fish kill in Bengaluru lakes in 2022: Report

BENGALURU: A report titled ‘Fishkill in Lakes of Bengaluru (2017-2022)’ recently released by ActionAid noted that a total of eight instances of fish kill have been reported in the lakes of Bengaluru within 7 months of 2022. The number surpasses the annual fish kill numbers in the last five years.

The ActionAid report noted that while six incidents were reported in 2017 and 2018, the number had come down during the lockdown years, that is, between 2019 and 2021. In the last five years, a total of 32 incidents of fish kill have been identified in the city lakes.

The ActionAid report is a secondary research that is based on news reports. It also identified four vulnerable lakes of the city based on the number of times of incidence, which are prone to fish kill. The Haralur lake alone has experienced three incidents of fish kill in past five years. The lakes of Madiwala, the Bellandur, and the Kommaghatta have had two incidences each.

The report found entry of sewage into the lakes to be the most common factor in most of these incidents – it has been identified as the main reason for 51 per cent of the cases of fish kill in city lakes. Toxins and chemicals are the second most common reason for the cases reported as it accounted for 23% of the cases. Other than these two, industrial effluents, pesticides, and fertilisers, and sewage treatment plants were noted as other identified causes.

In response to the report, Bruhat Bengaluru Mahanagara Palike (BBMP) officials commented that sewage has not been the reason behind the incidences of fish kills. Ravi K V, Executive Engineer, Lakes, BBMP, said that fish kills happen when it rains and silt flows into lakes through drains; these slit particles get accumulated in the gills of the fish, which causes oxygen deprivation in them, leading to their deaths. He added that this is the reason why many cases of fish kill happen around the rainy season.

However, the ActionAid report noted that except for the month of August, incidences of fish kill have been reported in all months in the last five years – most of those incidences occurred in May and December. T V  Ramachandra, Coordinator, Energy and Wetlands Research Group, Centre for Ecological Sciences, Indian Institute of Science, said that it is worrying that so many incidents have happened amidst rainfall – rainwater generally dilutes the water in the lake, so the continuing incidents must mean that the pollution levels in the lake have reached severe levels.

ActionAid has submitted its report, along with some recommendations, to the Chief Minister of Karnataka, Karnataka State Pollution Control Board, BBMP, Principal Secretary to Government of Karnataka (Environment and Ecology), and Additional Chief Secretary to Government of Karnataka (Urban Development). The report suggests regular monitoring of the city’s lakes, testing water quality and pollution in lakes, taking action against lake polluters, and avoiding the entry of sewage into them.