KMDA takes steps to prevent death of fishes, monitor dissolved O2 level at Rabindra Sarobar

kolkata: Kolkata Metropolitan Development Authority (KMDA) is developing its own infrastructure for more frequent measurement of dissolved oxygen level at Rabindra Sarobar, so that prompt interventions can be made. The move comes with some fishes found floating dead at the national artificial lake that stretches over an area of 3.5 km. Experts have attributed the reduction of dissolved oxygen as the primary cause behind the death of fishes.

"We are procuring some machines for measuring the dissolved oxygen level of Rabindra Sarobar. These will be placed at 12 to 15 strategic locations and the oxygen-level will be monitored on weekly basis. We will maintain a register and whenever we find that the dissolved oxygen has got reduced, potassium permanganate and calcium oxide will be put into the water for artificially increasing the dissolved oxygen level. This will prevent death of fishes," a senior KMDA official said.

Presently, West Bengal Pollution Control Board (WBPCB) measures the dissolved oxygen level in water and the exercise is conducted every month.

"We have collected samples for examination and the water quality report will come by next week. KMDA has also asked us to give some suggestions which we will do, once we have the report in hand," Kalyan Rudra, chairman of WBPCB said.

The KMDA official said the sustained cloud cover for four – five days at a stretch has apparently reduced the amount of dissolved oxygen in water and the fishes have died because of oxygen deficiency.

When this happens it is often seen that fishes come up on the water surface and struggle in the water. This behavior of fish is common in any waterbody when the sun is not witnessed for a long time period.

"It is difficult to attribute specific reason, unless we visit the spot and examine the water. But apparently it may be some ecological problem," Sumit Home Chowdhury, Professor of Zoology, Calcutta University who specialises in Fishery Sciences said.

Another official of KMDA also did not rule out the fact of mixing of road water with fresh water of the lake leading to contamination. "However this chance is too feeble, as per consultation with experts," he added.

KMDA, the custodian of Rabindra Sarobar is also preparing a DPR for placing aerators at different places in Rabindra Sarobar for increase of dissolved oxygen level in water. "We are also taking measures for repair of the fountain adjacent to Nazrul Manch which has been lying defunct for some years," a KMDA official said.