Assessing of Water Quality of Lake Dogodogo in Burundi Based on Zooplankton Diversity Indices

Abstract

A study of zooplankton diversity and water quality of Lake Dogodogo located in West Burundi was carried out from April to July 2021 in six sampling stations, with four selected in the littoral zone and two remaining in pelagic one. The main objective was to assess the water quality using zooplankton diversity indices for a better management of this fishery resource essential for the surrounding populations. The zooplankton sampling was collected twice a month between 8 A.M and 11 A.M each time. The samples were taken vertically using plankton net with a 50 µm of mesh size, 26 cm in diameter and 0.5m depth. We recorded 30 zooplankton species, 19 of rotifers, 9 of copepods and 2 of cladocerans. The number of species varied from one station to another and from the littoral zone to pelagic zone. The abundance of zooplankton was higher in the pelagic zone than the littoral one. We then highlighted species specific for pelagic zone, such as Anuraeopsis fissa, Brachionus angularis, Brachionus calyciflorus, Brachionus falcatus and Keratella tropica. These latter are indicators of a high trophic level. According to the diversity indices calculated, the Dogodogo’s water quality is moderately polluted by a low level contamination of agricultural origin. Therefore, it is necessary to protect this important resource for fish production purposes, which is essential in protein supply for human life.