Abstract

Introduction: Contaminants generated from different human activities combine to pose stress on the benthic macroinvertebrates and alter their community structure. Aim: To evaluate the impacts of human activities on the Lagos lagoon, by examining changes in abundance and diversity of benthic macroinvertebrates. Materials and Methods: Eight sampling points with varying human impacts along the edges of the Lagos lagoon were investigated monthly between September 2020 and February 2021, for the effects of human-induced stress on the abundance and diversity of benthic macroinvertebrates in the study area. Water and benthic macroinvertebrates were collected monthly using Hydrobios Water Sampler and Van-Veen grab respectively, and analysed in the laboratory using standard methods. Results: The hydrochemistry of the stations differed significantly (P<0.05), with the exception of temperature. A total of 1390 individuals, comprising twelve species, eleven genera, six orders, four classes and three phyla were recorded. The benthic macroinvertebrates assemblage was dominated by relatively pollution-sensitive and tolerant species such as Tympanotonus fuscatus and Nereis diversicolor. There was a generally low abundance and diversity of benthic macroinvertebrates in the study area, and this may be attributed to the combined impact of different anthropogenic activities in the study area. The low abundance and diversity of benthic macroinvertebrates indicate an overall decline in water quality and ecosystem health. Conclusion: This highlights the need for better management of anthropogenic activities in the area, to maintain a healthy aquatic environment.

Keywords: Anthropogenic influence, Water chemistry, Benthic macroinvertebrates, and Lagos lagoon