Ecological impact of brewery effluent on the Ikpoba river, Nigeria, using the fish communities as bio-indicators

Abstract

This study examined the impact of brewery effluent on the fish communities of the Ikpoba River. Out of the 28 species caught, 22 occurred in station 1 and 28 species in station 2 (the control). Malapterurus electricus and Syndontis nigrita were dominant. Six species were present in station 2 but absent in station 1. Mastacembelus leonnbergii is being reported for the first time in the Ikpoba River. The overall abundance of the fish species was significantly higher (P < 0.05) in station 2 than in station 1. Species richness and general diversity were also higher in station 2. The two similarity indices (Bellinger's and McNemar's coefficients) computed to compare the two stations showed significant dissimilarity in the fauna composition of both stations. Although chironomid larvae formed a major part of the fish diet in the study stretch, the fishes in station 1 almost exclusively fed on Chironomus larvae, which are known indicators of organic pollution. This study further reveals that besides the use of diversity indices and routine community parameters, the food and feeding habits of fish can also be used in assessing the degree of pollution originating mainly from organic sources.


Key words: Nigeria, Tropics, River, brewery effluent, fish, impact assessment, bioindicators.


Journal of Aquatic Sciences Vol.17(1) 2002: 35-44