Species composition and biomass estimates of zooplankton in some water bodies within Lake Victoria basin

Abstract

Zooplankton communities were identified and their abundance and biomass estimated in some selected satellite lakes and Mara River in Lake Victoria basin, during wet and dry seasons in 2002. Samples were collected from eight water bodies. Three stations were sampled from each water body using a plankton net (40 µm mesh size) hauled vertically through the water column. The zooplankton community comprised mainly crustacea and rotifers. The results show that the number of species collected during the wet and dry seasons was 31 species and 28 species, respectively. The Shannon wiener diversity indices were not significantly different (Mann-Whitney U Test = 16.000, p = 0.1049). The rotifers were the most dominant during both seasons. The wet season recorded higher biomass in all satellite lakes than during the dry season (t = 2.476, DF = 9, p = 0.0176). On the contrary there was a higher biomass during the dry season than during the wet season in Mara River (Mann-Whitney U Test, = l.000, p = 0.0150). Tanzania Journal of Science Vol.30(1) 2004: 43-52