Parasites and Macroinvertebrates as Indicators of Environmental Stress: The Case of Mindu Catchment Area

Abstract

A total of 42 fish belonging to ten different species were sampled from the Mindu Dam and analysed for parasites. Oreochromis urolepis were infected by four parasite species, while Brycinus lateralis was infected by one parasite species. The macroinvertebrates were sampled from four sites in the Mindu catchment area, sorted and classified into three ecological categories; 19 families of macroinvertebrates were classified as pollution tolerant and most of these species were collected from the tail race of the dam. 15 families were intermediate in terms of pollution tolerability and three families belonged to a pollution sensitive group. Most of the metallic ions were detected from the sediments. Zink, Chromium and Lead were detected in all the samples from all the sampling localities except in Ngerengere river (Zn- water sample) and the dam’s tail race (Cr-water sample). Mindu dam is under strong anthropogenic pressure due the increase in human settlements around its catchment area. In addition people cultivate in the nearby surroundings and use pesticides and fertilizers to nourish their crops, the residues of which are constantly being washed into the dam. All these contribute to undermine the health of Mindu as a habitat and as such disturb biological diversity in the dam