Most coastal waters are exposed to high influx of pollutants due to the obvious elevated human activities. In order to adequately evaluate the extent of toxicity of contaminants in the ecosystem, and their synergistic effects, marine ecologists prefer biomonitoring to chemical approach. The benthic macroinvertebrates, due to their sedentary mode of life and residence at the sediment-water microcosm, are regarded as the most veritable tool for biomonitoring. This is because these organisms are impacted by the interstitial forces of the sediment-water interface in the marine ecosystem and also serve as the main channel for the interchange of biomass. This review focuses on the biomonitoring status and prospects of a coastal lagoon with reference to the benthic macroinvertebrates. The levels of biomonitoring activities which are suborganismal, organismal, population, community and ecosystem levels are critically analyzed. However, most of the molecular and biochemical assays, and biomarkers used in biomonitoring studies at the suborganismal and organismal levels of biological development are being outsourced. This poses great challenges to holistic biomonitoring programs in the vast Nigerian coastal ecosystem.
Keywords: Biomonitoring; Coastal waters; Lagos lagoon; Bioindicators; Benthic macroinvertebrates.