June 11: In a unique way to control the menace of malaria in Mumbai, the Brihanmumbai Municipal Corporation (BMC) will be introducing guppi and gumbusia larvivorous fishes at various water-bound places in the metropolis.As part of its integrated vector-control programme, the insecticide department of BMC will rely more on biological control rather than chemical control. The state government has also realised the ill-effects of using more and more insecticides. This method was used earlier too, but this year after the monsoon, a massive drive will be understaken wherein a large number of fishes will be introduced in various water reservoirs, ponds, nallahs, big potholes and other places where mosquitoes can breed, S R Khanolkar, insecticide officer of BMC said. The guppi and gumbusia, which are about an inch to one-and-a-half-inch in size, breed very fast and voraciously eat mosquito larvae.

Both guppi and gumbusia belong to the pocilia rseticulate family of fishes and are inedible, Khanolkar said. These larva-eating fishes are light or pale brown in colour. Other fishes that can be used are telopia and blue gill. ``If we use telopia and blue gill, people will start fishing them out,'' she remarked. However, guppi and gumbusia are not suitable for highly-polluted water. They are ideally suitable for roadside drains, monsoon drains, reservoirs, ditches, garden tanks and swimming pools, Khanolkar added. To promote this technique, the BMC proposes to construct more hatcheries, M P Jayprakash, assistant insecticide officer of BMC informed. It is also planned that there should be at least one hatchery per ward.

Jayprakash said using fishes for the integrated vector-control programme is the most environment-friendly and economically viable method to check the growth of malarial larvae.

However, the need of the hour is to spread awareness about biological control and construction of hatcheries. And the word of caution is the overcrowding of fishes in hatcheries. As guppi and gumbusia breed very fast, a large chunk of fishes has to be taken out from the hatcheries and released in water sources at regular intervals.

Copyright © 1997 Indian Express Newspapers (Bombay) Ltd.