ASSESSMENT OF BENTHIC MACRO-INVERTEBRATE FAUNA IN TWO CONTIGUOUS COASTAL WATER BODIES WITHIN BARRIER LAGOON COMPLEX, WESTERN NIGERIA

Abstract

As a means of assessing ecological status in the westernmost part of the Barrier Lagoon Complex in western Nigeria, compositions and distributions of benthic macro-invertebrate fauna were studied in two contiguous water bodies within the complex, Badagry Creek and Ologe Lagoon. Samples of benthic macro fauna were collected from five stations in each of the two water bodies and analysed using standard methods both in the wet (June and September 2011) and dry (February and April 2012) seasons. A total of eighteen benthic macro-invertebrate species belonging to classes Bivalvia, Gastropoda, Crustacea and Polychaeta were recorded in Badagry Creek while from Ologe Lagoon, a total of thirteen species were recorded belonging to Classes Bivalvia, Gastropoda and Oligochaeta. Organic pollution tolerant species of polychaetes and oligochaetes were recorded in the two water bodies only at the stations close to municipal wastes discharge points. Higher macro-invertebrate abundance levels were recorded from the two water bodies in the dry than wet season. Badagry Creek recorded higher macro-invertebrate abundance (589 and 632 in wet and dry seasons respectively) and diversity indices values than Ologe Lagoon (with 92 and 404 abundance values during wet and dry season respectively). Relatively very low benthic macro-invertebrate abundance and taxa number were recorded from the stations close to sand mining activities especially in Ologe Lagoon. The implications of the anthropogenic activities on the benthic macro-fauna in relation to sustainable management of the water bodies and resources therein are discussed.