Investigation of Seagrass Bed Distribution in Brass Estuary, Bayelsa State

Seagrass meadows are among the most productive and ecologically valuable coastal habitats globally, providing nursery functions for juvenile fish, sediment stabilisation, carbon sequestration, and water clarity maintenance. This study investigates the spatial distribution, species composition, and health status of seagrass beds in the Brass Estuary, Bayelsa State, South South Nigeria, an area subject to oil-related activities, anchor damage, and increasing turbidity from upstream deforestation. Seagrass surveys are conducted by trained SCUBA divers at twelve stations during the dry season of 2024, following the SeagrassNet monitoring protocol. Species are identified using morphological features, percentage cover is estimated using 50 by 50 centimetre quadrats, and shoot density is counted at each station. Leaf area index, above-ground and below-ground biomass, and sediment characteristics are measured to assess bed productivity. Water quality measurements including light attenuation coefficient, turbidity, and nutrient concentrations are related to seagrass distribution patterns. Satellite-derived water clarity data from Sentinel-2 MSI imagery extend spatial coverage beyond dive survey areas. Species detected are expected to include Halodule wrightii and Thalassia testudinum, with the highest cover in clear, shallow, sandy-bottomed channels. Turbidity is identified as the primary limiting factor in estuary inner zones. Recommendations include anchor exclusion zones and oil spill buffer distances around documented seagrass beds. Keywords: seagrass meadows, Brass Estuary, Bayelsa, marine habitat mapping, estuarine ecology