Cage farming is an old fish farming system across the world, especially in the Far East. In Africa, it was first piloted in West Africa and then on Lake Kariba in Zambia in the 1980s.
In Uganda, feasibility studies started in the 1990s at the National Fisheries Research Institute in Jinja.
How it works
Fish cages are placed in lakes, ponds, rivers or oceans to contain and protect fish until they can be harvested.
The method is also called off-shore cultivation when the cages are placed in the lake. Fish are stocked in cages, artificially fed and harvested when they reach maturity. The cages vary in size.
The boxes are interlinked by pipes and a wooden bridge on which caretakers access them during harvesting and feeding.
The interlinked structure can be as long as 100 metres.
The success of cage fish farming depends on the availability of water and materials for construction of the cages.
In Uganda, in addition to Lake Victoria, there are smaller lakes across the country on which the cages can be fixed.
Before one makes a selection of a spot for the cages, serious studies must be undertaken to, among others, determine the depth of the water and the nature of the wind/waves at that particular spot.
In terms of materials, the cage requires a metallic mesh that is placed in a section of the water body. The cage is attached to floaters to ensure that it does not sink.
The cage is only opened during feeding and harvesting. The advantage here is that there is no need for water quality control, since this water is recycled within the lake.
The fish in cages is easy to feed. They are fed on floating pellets.
Because of the easy and targeted feeding, the fish grow faster.
The system is good for replenishing fish stocks in the lake and at the same time increasing the catch.
A farmer can have a good harvest every after six to seven months after stocking.
With cage fishing production is predictable, which is not the case with fishing in the wild. You may go out with 100 nets and you come back with two fish. But if you have your cage and you have looked after these fish very well, you can predict the production and even the money that you can learn from it.