Kolkata: Dead fish were found floating in Rabindra Sarobar by morning-walkers on Sunday, raising questions about the deteriorating quality of the lake water. A large number of fish had died at the lake a few months ago. Experts said a drop in dissolved oxygen level of the water could be a reason behind the deaths.
A large fish was found floating dead near gate number 1, close to the Buddha temple, on Sunday morning, along with hyacinth and plastic bags and bottles.Lake regulars said at least six such large fish were found in the waterbody over the last few days.
Officials of Kolkata Metropolitan Development Authority (KMDA), the custodian of Sarobar, said there are some spots in the lake where sunlight can’t reach and the water’s dissolved oxygen level often fluctuates. “This could be an isolated case as the spot usually has adequate sunlight. The sky has remained partly cloudy in last few days which may have made the dissolved oxygen (DO) level fluctuate. As per our daily DO level reading, it remains in the range of five to six which is about normal,” said an official.
Environmentalists said there were a few reasons for which fish have been dying in the last few days. “Cloudy weather, low water temperature and low DO level are the usual causes. Due to high wind velocity in last five days, the toxic particles have been flowing into the lake. Also, visitors often throw food into the lake which is bad for the aquatic fauna,” said environmentalist Somendra Mohan Ghosh. KMDA said they conduct regular maintenance of Sarobar. “In last 15 days, the water level has dipped by less than an inch. That might be due to normal evaporation and no rainfall,” said an official.