The Kenya Marine and Fisheries Research Institute has created a map to guide installation of fish cages in Lake Victoria.
This follows massive fish kills that have made farmers in Kisumu and Busia counties to suffer losses worth millions of shillings.
To stop this, KMFRI has identified ideal locations for cage fish farming, ensuring maximum production and risk mitigation.
Fresh water systems research director Christopher Aura said the areas have been mapped through research and consideration of economic factors.
“Research has informed mapping by considering factors such as water quality, depth, security and proximity to landing sites,” he said.
Additionally, the mapping also considered fish breeding grounds and currents in the lake, which lead to upwelling, a natural phenomenon, which causes deep cold water to rise to the surface.
The recent massive fish kills in Busia have been attributed to upwelling.
“When upwelling occurs and the deep waters come to the surface it leads to fish kills because the water lacks sufficient oxygen due to decomposition of organic matter, depleting oxygen,” he said.
The phenomenon, which has been documented in Lake Victoria since 1990, primarily occurs in May, June, September and October.
“It is not new and it occurs even in the natural environment. The reason why we are having massive fish kills in cages when upwelling occurs is because the fish cannot escape when there is oxygen deficiency,” he said.
The suitability map states that farmers should not place cages in shallow water since a depth of six to 10 metres, though suitable, is prone to negative effects of upwelling.
Aura asked farmers to join hands and install cages at the locations identified by the agency to benefit from the venture.
“Locations in deep waters are the most suitable. However, a lot of resources are required to build the cages and ensure security,” he said.
Aura urged farmers to invest in oxygen metres and regularly check oxygen levels in the cages to avoid losing their stocks, adding that farmers must invest in cold storage facilities to harvest and store their fish in the event of an emergency.
“Farmers must also regularly check on the quality of water and make informed decisions to avoid losses,” he said.
Lake Victoria, according to KMFRI, has an estimated carrying capacity of 25,427 cages.
However, the natural resource
currently contains 6,000 fish cages
covering 62,132 M2 with an annual
production capacity of more than
10,000 tonnes – largely of Nile perch
and tilapia.