Date:16/05/2005 URL: http://www.thehindu.com/2005/05/16/stories/2005051615370300.htm

Karnataka - Bangalore

Dead fish being removed from lake

Staff Reporter

`Fall in oxygen level cause for fish kill'

BANGALORE: Fish that died in Vengaianakere in Krishnarajapuram are being removed from the waters and buried on the banks of the lake. Preliminary investigation by the Lake Development Authority has revealed that the fall in the level of desired oxygen in the lake caused the death of the fish.

Fish such as silver carp, grass carp, and small "jilebi" were found dead in the lake. According to the residents of the area, fish were found dead on Wednesday. People, who use the banks of the lake for walking, reported the fish kill for the first time to the authorities.

On Sunday, officials from the Krishnarajapuram City Municipal Council and the Lake Authority and the Department of Fisheries visited the lake. Five labourers were removing dead fish and burying them.

According to Vanashree Vipin Singh, Deputy Conservator of Forests (Lake Development Authority), the desired oxygen level could have fallen because of flow of sewage water into the lake. The minimum level required was 4 mg/litre. Depletion occurs because of high organic content and also of high temperature, she said.

She told The Hindu that a team from the authority, which visited the lake on Saturday, found sewage containing plastic bottles and other waste flowing into the lake. Sewage was flowing into the lake as a drainage line was blocked because of dumping of debris. "Sewage results in growth of water algae, which also consumes oxygen," she said.

She said the Karnataka State Pollution Control Board (KSPCB) officials also visited the lake and had taken samples of water and dead fish for investigation.

"Only after we receive results of the investigation we can pinpoint the reason for the decrease in the biological oxygen demand that indicates the amount of oxygen required for maintaining the purity of the lake water. It will take three days for the KSPCB to give the results," she said.

A fish kill was reported in Ulsoor Lake in January. The Karnataka State Pollution Control Board team had found that the oxygen level had come down to between one milligram per litre of water and 1.9 milligram per litre as against the normal 4 mg/milligram per litre.