Fishy deaths
Tests carried out by the Karnataka State Pollution Control Board (KSPCB) after this year's third incident of large-scale fish death in Bangalore's lakes have prompted official agencies to attribute them to sewage ingress. But researchers believe this doesn't explain tonnes of fish dying at one stroke.
Five tonnes of fish died in Puttenhalli Lake in mid-June 2004, two tonnes died in Vengaiahnakere Lake in May 2005 and 3.5 tonnes died in Ulsoor Lake the same month. KSPCB's tests point out that dissolved oxygen content was below average, mainly because of sewage inflow, in all these cases. But R K Somashekar, who heads Bangalore University's Environment Science Department, doesn't agree with the board's hypothesis: "Large-scale sudden fish death cannot happen because of reduced dissolved oxygen content