Zooplankton communities of some tanzanian lake victoria basin water bodies

Abstract

A survey of the zooplankton communities of some Tanzanian Lake Victoria Basin water bodies was conducted during September/October 2000 and March/April 2001. Plankton nets of mesh sizes 100 mm and 65 mm respectively were used to collect qualitative zooplankton samples from the water bodies on two occasions September/October 2000 and March/April 2001. The samples of zooplankton collected were made up to twenty taxa of rotifers and thirteen crustaceans. The most frequently encountered rotifers were Asplanchna spp., Brachionus angularis, Brachionus caudatus, Brachionus calyciflorus, Brachionus patulus, Keratella cochlearis, Keratella tropica, Keratella quadrata, Lecane bulla, and Synchaeta spp. The most common crustaceans were Thermocyclops emini, Thermocyclops neglectus and Diaphanosoma excisum. In terms of numerical abundance, Kyarano Dam contributed the highest density. In September/October 2000, when the mean total number was 179,689 m-2. In March/April 2001 the highest density of 479,015 m-2 was observed in Lake Ikimba. The structure and composition trends of zooplankton in the surveyed water bodies may be related to both intensity of predation and limitation by environmental factors, which may include the nature of the water bodies, and food quality and quantity.