Sunday, August 23, 2009
Fish Culture: Freshwater Fish Farming: Hobby and Business
Abe V Rotor
There are three ways freshwater fish can be cultured as pastime or business.
1. Family fishpond
2. Palay-isdaan (rice-fish culture)
3. Cage culture
A family fishpond is an enlarged version of a home aquarium. The requirements in taking care of the fish are basically the same – clean water, good aeration, sufficient feeds, suitable temperature range, absence of pollution – and above all, TLC (tender, love and care).
No wonder the aquarium is a source of joy to adults and children alike. And the ambiance it lends to the environment is therapeutic, especially for one who comes home after a hard day’s work. It brings the whole family together on weekends.
I missed my outdoor sports as a fisherman-enthusiast when I moved to the city some years back. To compensate for it I built a garden pond with a dimension, 4 meters long, 2 meters wide and one meter deep, and stocked it with some two dozen juvenile catfish for fattening. Three months after and the fish were ready for harvesting, I would gather the family into a backyard picnic, and how we all enjoyed inihaw na hito.
If you are living in the province, the conditions there are better. These are the things you can do.
1. You can enlarge the size of the pond so that you can raise fish for the family and the neighborhood. You can have separate ponds for tilapia, hito, gurami – or bangus, if you are living within the estuary.
2. Make use of the natural topography of the land using the lowest part (basin) as the pond. Be sure you have sufficient running water. If not, have a deep well ready to augment water supply. To reduce loss of water through leaching, compact the bottom with clay. There are now plastic sheets used as fishpond lining.
3. Stock your fishpond with fish of the same kind and size so that they will grow evenly. When raising tilapia, avoid overcrowding. Tilapia reproduces very fast. Stocking with all male tilapia is important in obtaining even and fast growth.
4. It is cheaper to formulate your own feeds than to depend on expensive commercial feeds, especially where rice bran and fishmeal are readily available. Kitchen scraps, such as fish and poultry entrails, are a good feed supplement. Avoid excess feed as this is likely to accumulate and decompose.
5. A pond has good natural food supply if it is rich in plankton. The color of the water is usually bright green. Plankton organisms are microscopic and highly diverse. Phytoplankton (mostly green algae) are photosynthetic, and together with the zooplankton (microscopic animals called protists), form the base of a complex food web, on which the fish ultimately obtain their nourishment. To increase plankton population fish farmers use appreciable amounts of nitrogenous and complete (NPK) fertilizer. Care should be observed not to induce overproduction of plankton because this causes the so-called algal bloom. Plankton decomposition, exacerbated by over feeding, increases produces hydrogen sulfide and methane gas, increases carbon dioxide level, and reduces dissolved oxygen. Foul odor forewarns of disaster. Replace the foul water immediately with fresh water.
6. A fence made of nylon net is recommended during the flood season, especially in low-lying areas. This will also serve as a rail guard for the safety of children and pets.
7. For intermittent ponds, harvesting is done when water supply is low. This allows the fishpond to dry up, ready for the next season. In farming we call this fallowing or resting the land. This is true also with fishponds. For fishponds with sufficient water throughout the year, harvesting is done with lift net, selecting only the big ones, and allowing the small ones to grow. For Nile tilapia (T. nilotica), three pieces make a kilo is ideal, for hito, four pieces.