NewDelhi Sep 7 : The Firozabad administration in Uttar Pradesh is releasing about 25,000 mosquitofish in the wake of a deadly outbreak of dengue and viral fever that has claimed 51 lives so far.
Bred in ponds, wells and smaller water bodies, these fish are known to check the spread of mosquito-borne diseases like malaria and dengue.
Named for their ability to feed on mosquito larvae, they are generically known as Gambusia. They are used by health departments across states to curb dengue and malaria. Packets of fish seedlings are simply released in water bodies, following which fully grown fish devour close to 100 larvae daily.
Known to inspire terror in mosquitoes, Gambusia have a voracious appetite and mosquito larvae is just a small portion of their diet. They also feed on zooplankton, mites, beetles and other invertebrates.
According to a report in The Tribune, Dr Kanwarjit Singh, joint director of animal husbandry and fisheries, Chandigarh UT, said adult Gambusia could eat up to 150 mosquito larvae in an eight-hour period. This makes them an excellent biological tool for mosquito control because they eat the larvae before they have a chance to develop into adult mosquitoes, he added.
In 2019 and 2020, use of this fish was deemed to be successful in curbing the spread of dengue and malaria in Gurugram, according to a report in Times of India.
Even World Health Organization (WHO) has studied the use of fish in mosquito control. According to a 2003 paper published by WHO’s regional office for the eastern Mediterranean, Cairo, this strategy of using certain species of fish that feed on mosquito larvae targets the larvae rather than the adult mosquitoes and is potentially safer as it does not involve use of insecticides. The paper also states that indigenous or exotic fish with a known larvivorous potential can be used for larval control and have been scientifically proven to be effective in malaria control.
These fish have the ability to survive in shallow water bodies, known to be optimal mosquito breeding grounds, and are hardy enough to go about thick weeds.
Biological Weapons
Many health departments also use guppy fish to check the spread of mosquito-borne diseases. They are bred in the same manner as mosquitofish. ‘Guppy drives’ have been carried out in Tamil Nadu, West Bengal and even Gujarat, while Gambusia have been used by civic administrations in Punjab’s Mohali and Amritsar and Haryana’s Panchkula, along with capital Chandigarh.
However, the use of Gambusia and guppy fish as biological weapons to control mosquito menace have had quite the opposite effect as well. Four hatcheries of the Cuttack municipal corporation in Odisha have turned into a breeding ground for mosquitoes, according to a report in The New Indian Express. This is because all the hatcheries have been lying defunct over the past several years due to lack of maintenance, turning into breeding grounds for mosquitoes due to stagnation of rainwater.