Mosquito fish: PHL's hope to get rid of dengue

June 28, 2012 9:38 pm 

By Leonardo V. Micua

DAGUPAN CITY, June 28 — A tiny tropical fish found anywhere in the Philippines could be the ultimate answer to the country’s perennial problem on dengue which is putting at risk the lives of thousands of Filipinos, especially children, yearly.

This is the mosquito fish (bombosia assinis), so called because of its habit of feeding on larvae of mosquitoes left on stagnant water by the adult flyer.

Dr. Westly Rosario, chief of the Dagupan-based National Integrated Fisheries Technology Development (NIFTDC), said scientists used the mosquito fish in licking malaria from 1920 to 1950.

Malaria then was not confined in tropical countries but also in temperate countries, like Russia and those in Europe.

Now that dengue is pestering the Philippines all-year round, especially during the rainy season, it is about time to redeploy the mosquito fish in all stagnant water where mosquitoes are laying their eggs, Rosario said.

The mosquito fish, popularly known as “itar”, “milyon” or “kataba” in Tagalog-speaking provinces of Luzon, eats larvae as big as its size daily.

Very voracious, a mosquito fish that weighs one gram also eats one gram of larvae daily.

Because of their diet and feeding behavior, scientists believe the fish can be used extensively in eradicating mosquitoes that cause both malaria and dengue.

What is unique in the mosquito fish is it can live in even very poor environmental condition or in water that is shallow and murky and in water with low dissolved oxygen.

Rosario said the fish can also eat organic matters and when there is no more organic matter or larvae that it can feed on, it can turn cannibalistic and eat smaller mosquito fish.

The mosquito fish multiplies rapidly but unlike other fish, it lays eggs but hatches the eggs internally. When when it finally brings them out, it is not the eggs that come out but new fishes already.

This means under this system of reproduction, said Rosario, there is 100 percent chance that the eggs laid by the mother mosquito fish would live. As eggs, there is probability that they cannot be all hatched.

Rosario said that in the 1950s, the main issue that cropped up was that the reproduction of the mosquito fish was faster than ordinary fish, precisely because of the former's unique reproduction system.

He said a female mosquito fish mates once but it has the unique capacity to store male sperm in its system, so its reproduction still continues even when mating again with the male fish.

The NIFTDC is now collecting mosquito fish that teems around its compound and once they have enough, they will go to the different schools and stock these in canals and ponds nearby to eat larvae that will turn into adult mosquitoes in a few days.

This way, Roario said, they may be able to contribute in eradicating or minimizing the incidence of dengue in Dagupan and Pangasinan which usually soars during the rainy days.

At the same time, he announced that officials of a town in Ilocos Sur already came to NIFTDC to ask for some mosquito fish to be stocked in their canals and ponds in a bid to get rid of dengue.

Rosario said the mosquito fish is also edible, adding that being small, it is sometime mixed with "butobot” that is sold in the market as food fish.

A female mosquito fish grows up to seven centimeters and five centimeters for the male.

Like the tiny "butobot", the mosquito fish is also fed to aquarium fish, like arowana.



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