Characterisation of Estuarine Habitats in the Bonny Estuary, Rivers State, Using Remote Sensing

Remote sensing technology offers cost-effective tools for large-scale estuarine habitat mapping, providing critical data for environmental planning and biodiversity conservation. This study characterised and mapped the estuarine habitats of the Bonny Estuary, Rivers State, South South Nigeria, using multispectral satellite imagery and geographic information system techniques. Landsat-8 and Sentinel-2 imagery acquired between 2022 and 2024 were processed using ERDAS Imagine and ArcGIS software to classify and delineate habitat types including mangroves, open water, tidal mudflats, sandy shores, and aquaculture ponds. Normalised difference vegetation index values were computed to assess mangrove health status. Ground-truthing surveys were conducted at 25 reference points to validate classification accuracy. Overall classification accuracy was 87.4 percent, with a Kappa coefficient of 0.83, indicating strong agreement between mapped and field-observed habitat types. Mangroves constituted the largest habitat class, covering approximately 620 square kilometres. Comparison with imagery from 2014 revealed a net mangrove loss of 12 percent over the decade, predominantly in the western creek zone adjacent to industrial facilities. Mudflat areas expanded by approximately 8 percent over the same period, indicating shoreline instability following vegetation removal. Aquaculture pond construction contributed to 4 percent of mangrove conversion. The study demonstrates the value of multi-temporal satellite analysis for tracking habitat change and strongly advocates for its incorporation into the environmental management systems of oil companies operating in the Niger Delta. Keywords: remote sensing, estuarine habitat mapping, Bonny Estuary, Landsat, mangrove change.