Dakshina Kannada Deputy Commissioner Sasikanth Senthil S. said here on Monday that the district administration has drawn up plans to launch a “guppy drive” in the coming days to let guppy fish into open wells and other water bodies in the city to control the breeding of larvae of dengue and malaria-causing mosquitoes.
Speaking at a meeting of principals and other heads of schools and colleges at the Town Hall, he said that guppy fish are being reared now for the purpose.
Mr. Senthil said that the drive to destroy mosquito larvae will continue for a year.
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An entomologist told the meeting that it would take 14 days for the birth of dengue-causing mosquito from the egg stage.
Meanwhile, the College of Fisheries, Mangaluru, told The Hindu that guppy fish can be one of the effective dengue mosquito control methods. Guppies adapt well to various types of confined water bodies and have been most commonly used. Each guppy fish can eat 25 to 50 mosquito larvae per day. This fish also has remarkable ability to reproduce and spread. It has a gestation period of 21-30 days, giving birth to fast-growing young ones. This fish can survive better in relatively polluted water.
Thus, introducing this fish in fresh waters will minimise the spread of mosquitoes by destroying larvae which spends its life cycle in the aquatic phase. Hence, it appears that the biological control of dengue vectors by fish would be advantageous, A. Senthil Vel, Dean, College of Fisheries, said.
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K.S. Ramesh, professor, and Suresh T. and S.K. Girisha, assistant professors, Department of Aquatic Animal Health Management in the college, said that the guppy method is viewed as being more cost-effective and more environmental-friendly than pesticides, though not as effective, and requires the continuing participation of the community.
“Though letting guppy fish into open wells and fresh water stock is an effective method of dengue mosquito control, we need to use other methods as well to make sure we are not harbouring larvae in our houses and gardens,” they said. The Aedes aegypti mosquito is the main vector that transmits the virus that causes dengue.
“Dengue infection rates are higher in outdoors and during the day when these mosquitoes (Stegomyia) bite most frequently. However, Aedes aegypti breeds indoors and is capable of biting anyone throughout the day. The indoor habitat is less susceptible to climatic variations and increases the longevity of this mosquito,” they said.
Mr. Vel said that the College of Fisheries has all the facilities that include several cement and earthen ponds within the campus. These ponds can be used for breeding and growing the fishes. If Mangaluru City Corporation provides necessary funds, the college can meet the requirements of this fish for Mangaluru region by next year.