The Public Health Department in the city has started breeding gambusia fish, which is said to be effective in checking mosquito breeding. The species, which predominantly feeds on the larvae is also called 'mosquito fish' and is being used as a biological control measure.
Speaking to The Hindu , P. Revathi, District Medical Officer, Tiruchi, said that a special tank was constructed at the Deputy Director of Health Services’ office and the fish was brought from the fisheries department.
Biological control measure requires a species to be introduced and a pest to be controlled.
In this case, the pests are mosquito larvae, and gambusia is an introduced species. Biocontrol, short for Biological Control, is the management of a pest, typically invasive species, by introducing a natural predator into the environment.
Nearly 120 villages and towns have been earmarked as ‘hotspots’ wherein these fish will be released in open wells and waterbodies, said Dr. Revathi. An adult gambusia fish can consume nearly 150 larvae in a day.
The problem of mosquitoes breeding in clear water, especially Aedes aegypti mosquitoes which carry the dengue virus can be controlled through them. While the fish are bred at the office, they are fed rice husks and groundnut oil cakes, commonly known as Kadalai Punnaku, she said.
These biocontrol measures are a lot easier to introduce in villages, especially in places where residents resist inspection, said Dr. Revathi.
“A junior entomologist was beaten up by villagers last week when he asked whether he could inspect their water fittings. They asked him to go clean the sewers. Notwithstanding the awareness programmes being conducted, people still believe that disease can only be spread through dirty water,” she said.
The introduction of gambusia fish in abandoned wells in the district has brought fever cases down drastically, claimed Dr. Revathi. When continuous fogging is done, the mosquitoes look for dark humid places to breed and abandoned wells with stagnated rainwater serve as an apt location, she said.
“Commonly, crude oil is poured into the well to stop mosquitoes breeding but it contaminates the well and it is difficult to clean. Instead, gambusia fish or even frogs can be released which will eat the larvae,” she said, adding that people interested in keeping the fish in their residences, in tanks or wells can collect them from the DDHS office.
Published - September 30, 2019 09:43 pm IST
