Aspects of the ecology of the crustacean zooplankton in the Sanyati Basin, Lake Kariba

Investigations on the zooplankton in Lake Kariba were carried out as part of a broader programme investigating components of the sardine, Limnothrissa miodon, food chain and factors affecting their productivity. This report deals mainly with the crustacean zooplankton, Bosmina longirostris and Mesocyclops leuckarti, which are the most important species in the sardine's diet. Factors which influence the number and distribution of the zooplankton are discussed. The relationship between the zooplankton and Limnothrissa are also briefly discussed.

Preliminary phytoplankton counts in the Sanyati Basin, Lake Kariba

Phytoplankton counts were made on a monthly basis on water samples, taken from one station in the Sanyati Basin. The results show seasonal fluctuations which are probably nutrient dependant. High phytoplankton numbers occur at times of high nutrient levels as was found with the crustacean zooplankton populations (Marshall 1980). Numbers also decreased with depth down to the thermocline. Below the thermocline there was little or no change in numbers.