From pixels to policy: Calibration of satellite-derived ocean water quality metrics to guide EBFM in Exmouth Gulf, Western Australia

Satellite-derived ocean water quality products offer cost-effective, broadscale monitoring solutions for ecosystem-based fisheries management. However, their application in nearshore, turbid environments requires rigorous validation. This study assessed the performance of satellite-derived sea surface temperature, turbidity, and chlorophyll- a products against a five-year (2016 - 2020) in-situ dataset from Exmouth Gulf, Western Australia; a remote embayment supporting key nursery habitats for ecologically, socially and commercially important fish and fisheries. In-situ loggers, Secchi depth, and datasonde deployments were compared with GHRSST, MODIS-Aqua, and CMEMS satellite-derived products. Strong alignment was found between satellite-derived and in-situ benthic temperatures during non-winter months ( R ² > 0.94), with winter overestimation likely associated with reduced vertical mixing under calmer conditions. Satellite-derived turbidity correlated well with Secchi depth ( R² = 0.805), and generalised linear models revealed spatial location and wind direction as primary turbidity drivers. In contrast, satellite-derived chlorophyll- a consistently overestimated field observations and showed no significant correlation, likely due to shallow water interference and low ambient productivity. A significant bushfire adjacent to Exmouth Gulf was serendipitously observed during the study in March 2018, revealed a compelling link between terrestrial disturbance and benthic light anomalies, supported by both in-situ logger data and satellite-derived turbidity. These findings highlight the value of integrating satellite and in-situ monitoring to detect environmental anomalies and support responsive fisheries management. This study demonstrates the utility and limitations of remote sensing for ocean water quality assessment in complex coastal systems and reinforces the need for site-specific validation when integrating satellite data into operational ecosystem-based fisheries management frameworks. • First known validation of satellite water quality in Exmouth Gulf using field data • Satellite sea surface temperature matched field data except in winter stratification • Satellite turbidity closely matched field data across seasons and locations • Chlorophyll-a products overestimated field data in shallow turbid waters • Bushfire-triggered turbidity anomaly detected using in-situ and satellite data