The evaluation of cage fish farming effects on water quality using selected benthic macro-invertebrate community parameters in the napoleon gulf, northern Lake Victoria

Abstract

Since the proliferation of cage fish farming in Uganda has raised concern over water quality deterioration, a study of the effects of cage fish farming on water quality in the Napoleon Gulf, Northern Lake Victoria was conducted during October 2012 to February 2013. Selected water column physicochemical parameters and benthic macro-invertebrates’ community parameters (i.e. numerical abundance, Shannon-Weaver diversity Index and modified Hilsenhoff Biotic Index) were analyzed monthly at both cage and non-cage sites. No significant differences were observed in physico-chemical parameter values, benthic macro-invertebrates’ numerical abundance and Hilsenhoff Biotic Index between cage and noncage sites. On the other hand Benthic macro-invertebrate species diversity differed significantly between the reference site and cage site 2 (P<0.05). Pollution tolerant Chironomus sp. and Melanoides tuberculata Muller, 1774 were significantly higher at the cage sites than the non-cage sites (P<0.05). These results suggest that cage fish farming significantly changed water quality.