Composition, abundance and distribution patterns of zooplankton in a tropical reservoir, Nairobi dam, Kenya

Abstract

The seasonal composition and abundance of zooplankton in Nairobi Reservoir, a small suburban water body, 1990 were investigated from October 1989 to September to establish taxonomic composition, abundance and seasonality of zooplankton in this Reservoir. zooplankton were sampled from vertical hauls from different (Station depths at three stations, a limnetic station 1) , a littoral station (Station 2) , and an inlet station (Station 3) , and concentrations of dissolved oxygen and chlorophyll ~, water temperature, total alkalinity, conductivity, Secchi depth, and rainfall were simultaneously measured. The findings show that there were trends in seasonal abundance of particular species with the composition varying both quantitatively and qualitatively. There was evidence of species succession among the three groups: Rotifera, Cladocera, and Copepoda with the abundance or dominance of different species at different times of the year. The seasonal variation in densities and species succession is discussed in relation to seasonal fluctuations of limnological parameters.