1 NOVEMBER 1998
BICYCLE PUMP-OPERATED SMALL-SCALE HATCHERY
Keeping in view the current socio-economic situation and the credit facilities available in rural Cambodia, in early 1996, a small-scale hatchery has been developed using locally available cheap resources. Efforts have been made to put together already existing low-cost locally available resources to develop this small-scale hatchery which could be an appropriate technology suitable for rural Cambodia.
The hatchery consists of a human-powered bicycle pump connected to a deep bore well, water jars, a breeding pool and hatching jars. The bicycle pump is a modified version of a double cylinder treadle pump. It is more convenient than the ordinary treadle pump as one can comfortably sit and pedal like on a bicycle to pump out water.
The two most important components in a hatchery are the overhead tank and diesel pump which eat up much of the total initial investment. While surveying the PADEK project areas it was realized that most people have a liking for a few cultivable species of fish such as tilapia, common carp, silver barb and silver carp. Tilapia being a prolific breeder its seeds can be easily procured from pond. The other two species are comparatively easier to breed with less water circulation in a hatchery. Therefore, to meet this specific need and to minimize the initial cost of establishing a hatchery, the modified treadle pump and the traditional water jars have been recognized as alternatives to the more expansive concrete overhead tank and diesel pump.
The traditional cemented water jars are locally made, cheap (each costs about USD$5-6) and almost every family in rural Cambodia owns one to store water. For the hatchery, 6 such water jars each with a capacity of 317 liters have been used. The bicycle pump is connected to a deep bore well and together with the water jars is fixed on a wooden platform at a height of 2.5 meters. The outlet is connected to one of the water jars through a conduit. All the water jars are interconnected to serve as an overhead tank. The breeding pool used in this hatchery is a 2.0 meter diameter and 0.75 meter deep circular tank.
The breeding pool is provided with a 0.5 inch diameter circular perforated PVC pipe on top to sprinkle water and three lateral inlets of 0.75 inch each to create water circulation. The bottom of the tank is sloped down to its center to create proper drainage and overflow system. For hatching of fertilized eggs, 12-liter tin jars were used. The jars were made with the help of a local blacksmith in such a way that a portion of each jar has a 28x13cm^2 thick transparent plastic sheet attached to its body to monitor the hatching process. Water is let in from bottom through a detachable plastic pipe and the operation is similar to that of a glass jar hatchery. These jars are cheap (each costs US$10), durable and also easy to maintain.
The hatchery has been successfully operated on an experimental basis to produce seeds of common carp, silver barb and silver carp.
(excerpts from article by S.K. Das, M.C. Nandeesha, N. Heng, N. Ty in Aquaculture Asia, July-September 1998, Vol.III, No. 3: 18-19)