UIS aquaculture expert Johan van der Westhuizen has started a nursery and a hatchery for brine shrimp to use as feed for the growing freshwater fish population at his fish farm.
Van der Westhuizen's fish farm specialises in the breeding of tilapia and demand for fresh tilapia from his farm has been growing since its establishment in 2009. Since then, the farm has produced five tons of tilapia, which was sold on the local market.
The demand for tilapia in northern Namibia grows when the levels of dams and oshanas there drop after the rainy season.
To keep up with this demand, the Uis Tilapia Farm has to feed more fish, and fish food is expensive in Namibia, and not always readily available.
This is why Van der Westhuizen has decided to grow his own fish food in the form of 'artemia', or brine shrimp, on site. The tiny shrimp is found worldwide in inland saltwater lakes, and also in the salt pans at Swakopmund. The quarries at Uis are brackish and therefore ideal for cultivating artemia.
The ability of artemia to produce 'dormant eggs' called cysts has led to its extensive use in aquaculture. The cysts may be stored for long periods and hatched on demand to provide a convenient form of live feed for larval fish. From cysts, brine shrimp larvae can hatch in just one day.
Van der Westhuizen says he will initially produce artemia only to feed his own fish.
"For every ton of fish produced, 1,5 tons of artemia must be produced a month. By purchasing commercial fish feed, that's a bit much to do business with at the moment," he said.
The number of ponds in the farm's fish nursery will be increased so that fingerlings can be kept there longer before being transferred to floating cages in the old Uis tin mine quarry.
"Growing fingerlings in the ideal conditions at the hatchery optimises their initial growth rate, and so after relocation to the final grow out system, this growth rate will be maintained, resulting in a shorter production cycle," explained Van der Westhuizen.