Wednesday, February 17, 2016

The Backyard as Laboratory and Workshop series 1: Poecillia or Kataba - Nature's biological agent against mosquitoes

Dr Abe V Rotor
Living with Nature School on Blog [ ]

This fish is also called by other names like tora-tora in Marilao, and talundi in Bocaue and San Miguel. It is relative of the molly and guppy, which are favorite aquarium pets.

Kataba lives in the wild. It is abundant on the Pasig River, its tributaries up to Laguna Bay. Because it frequents polluted esteros and canals, it is also called canal fish. It is omnivorous, feeding on algae (lumot), decomposing matter, but prefers aquatic organisms. It is so voracious that it can eat nearly the equivalence of its body weight, its belly distended for which it got its name bubuntis or bubundat. It preys on kiti-kiti (mosquito wrigglers), and other aquatic insects and plankton organisms, thus serving as valuable biological agent in checking malaria and dengue which are transmitted by mosquitoes.

The late Dr. Grace M. Cruz of Bulacan State University studied the larvivorous characteristics of kataba, known as Poecillia latipinna, in a dissertation she defended for a Ph.D. degree at the UST Graduate School in 1998 and found out that six kinds of insects comprise its regular food along ther Marilao River in Bulacan. Other than mosquito wrigglers it feeds on leafhoppers (Nepothettix apicales), aphids (Aphis gossypii and A maydis), gamu-gamu or midges and red ants (Solenopsis geminata), a finding which confirms kataba is a farmer’s friend.

On the other hand, kataba is a voracious predator of other aquatic organisms, which include eggs and fry of valuable fish species, nymphs of dragonflies and damselflies which are themselves predators of kiti-kiti. There are few studies about this resilient fish and we do not even know if they are of any commercial value as human food.

Aquarium shops sell kataba to feed aruana and other predatory fish pets. Kataba is fished from rivers and lakes - and esteros, for this purpose, but the demand has greatly declined because the hobby of keeping aquarium fish is no longer popular.

One way to get rid of mosquitoes is to introduce kataba in stagnant water and waterlogged areas. It is Nature's biological agent against mosquitoes and mosquito-borne diseases. Kataba makes a good project in biology, particularly on the following aspects:
  • Life cycle
  • Feeding range
  • Salinity resistance
  • Pollution resistance
  • Pollution control
  • Species diversity
  • Food chain study in the ecosystem
  • Breeding experiments

Origin of Poeciliids

Poeciliids were introduced into the country from Mexico probably by “accident”. It must have been during the Galleon Trade between Acapulco and Manila. But certainly the colonizers knew of the value of this fish and it was possible that it was purposely introduced for biological control.

Today, poeciliids are found in many countries. With little encouragement, the fish multiplies very fast. Instead of laying eggs, it gives birth to numerous young viviparous. And being non-seasonal and highly adaptable, population levels are safely established in a short time.

How do we recognize the Pociliids? The fish has a barrel-shaped body, particularly in the case of the female which appears pregnant. Weight and length ratio shows that the female is more plump than the male of the same size.

The distinguishing mark of the male is the presence of gonopodium, which is the equivalent of a penis. Another is that the male’s dorsal fin is comparatively longer. The anal fin of the female originates beneath the dorsal fin, opposite the eleventh scale of the tail. The male’s anal fin, however, originates from beneath the anterior part of the dorsal fin opposite the eighth scale.

Practical Way to Clean Jars and Tanks

Makers of Basi wine (an Ilocano drink) and vinegar, use poeciliids to clean the earthen jar containerss. After harvesting the wine, the most difficult part of the job begins: cleaning the jar. It has to be washed at least three times in one-week intervals, allowing the water to stand every washing period. Its tedious work and the danger of breeding mosquitoes is inevitable.

By culturing two pairs of poeciliids in the jar, you only need to change the water once. And it takes half the time to obtain a clean, odorless jar. The secret is that the poeciliids eat the wrigglers, algae and plankton, as well as other organic materials, converting them into stable organic residues.

This is the same practice in cleaning glass aquariums, water tanks and garden ponds. Simply introduce some poecillids into the tank or pond and they will soon adjust to the new environment and in a short time reproduce and establish a stable population. It is one kind of fish you do not need aerators, re-circulating water pump, or any special gadgets. They simply thrive where other fish cannot. ~

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