44-16 The Crossroads of Productivity: Integrated PFZ Detection in the Ganges-Brahmaputra-Meghna Influence Zone

Abstract:

The northern Bay of Bengal (nBoB) is a socio-economically vital marine region, yet its fisheries face increasing pressure from environmental variability and climate-driven changes. Traditional identification of Potential Fishing Zones (PFZs) often relies on surface-level satellite data, which fails to capture the subsurface dynamics and vertical nutrient transport critical to fish aggregation. This study addresses this gap by implementing an integrated framework that combines field observations with a high-resolution coupled ocean-biogeochemical model, the Coastal and Regional Ocean Community (CROCO) model coupled with the PISCES ecosystem module.

The model was configured at a 9 km spatial resolution to simulate complex interactions, including nutrient cycling, phytoplankton growth, and wind-driven circulation. Validation against in-situ CTD measurements and satellite datasets showed strong agreement, particularly for sea surface temperature (SST) and chlorophyll-a distribution. Our findings identify thermal fronts (>0.04°C/km) and elevated chlorophyll-a concentrations as primary indicators of PFZs, with the most favorable conditions occurring in January. The results also emphasize the profound influence of freshwater discharge from the Ganges-Brahmaputra-Meghna (GBM) system, which sustains high coastal productivity even when wind-driven upwelling is weak. By integrating thermal structure, wind stress curl, and biological productivity, this study establishes a process-based approach for fisheries forecasting. This research provides essential insights for ecosystem-based management and the advancement of the Blue Economy in the region.

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.