Novatek gives tips on fish farming: Stocking and stocking density by Robert Kanyembo, Aquaculture Research and Development Manager, Novatek Animal Feeds Zambia
Extensive fish farming This is the level of least management in which there is low capital injection with the least yield per square metre. Under this level, we recommend stocking densities of 3 to 5 fish per square metre because fish depends more on natural food than supplementary feeding. Labour and investment costs are low and involves large systems with less fish. Semi-intensive fish farming Under this management level, care is taken in the production system to raise fish at a higher stocking density in a smaller area or volume. Moderate investment is made, and as such, supplementary feeding is given as well as natural feeding provided by pond fertilisation. The stocking densities ranges between 5 to 8 fish per square metre with frequent water exchange. Intensive fish farming Intensive fish farming involves fish stocked at higher densities of between 8 to 12 fish per square metre and above, and fish fed wholly on manufactured feeds. A significant effort is made to en-
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he topic of how much fish should be put in a production system has been of a growing concern and somewhat a detriment to aquaculture development. Many are the times fish farmers complain that their fish are not growing as they should or ask why fish die after attaining a certain weight of around 120 g and above. This is because around this stage, the biomass in the growing system would have increased as a result of increase in the average body weight of the fish stocked. Stocking by definition is the introduction of fish species into either a limnological (natural lake) or artificial system such as ponds, tanks, or cages. Stocking density relates to how much fish or weight is added per square area or cubic metre in a production unit. Stocking involves replenishing of limnological systems such as rivers, lakes, oceans, and streams to improve the dwindling fish numbers due to overfishing or natural elimination. In this context, stocking in aquaculture refers to introducing fingerlings into either ponds, cages, or tanks. It is very important therefore to understand how much fish to stock in your system and why. How then do you arrive at how much 4
fish do you stock per production system? The answer lies in your level of management. Management plays an important role in how much fish to stock per production system. In aquaculture or fish farming, there are basically three management levels that include extensive, semi-intensive and intensive, while others also include integrated fish farming.
Poorly managed fishpond.
Fish and rice farming.
ProAgri Zambia 63
