Spatio-Temporal Correlation of Sea Surface Temperature and Chlorophyll-a with East Seasonal Upwelling in the Bali Strait Using Aqua-MODIS Data

The Bali Strait is a critical fishing ground for the Sardinella lemuru (sardine fish) fishery. This study analyzed the spatiotemporal dynamics of sea surface temperature (SST) and chlorophyll-a (Chl-a) in the strait and their relationship with sardine fish productivity using Aqua-MODIS satellite data from February (rainy season) and July (dry season) 2025. Results revealed significant seasonal variations driven by monsoon-induced upwelling. During the July east monsoon, intense upwelling lowered SST to 26°C and elevated Chl-a to 11.14 mg/m³ south of Banyuwangi and Jembrana, indicating high biological productivity. In contrast, February conditions showed warmer SST (28.12–34.49°C) and lower Chl-a, consistent with reduced upwelling. A strong inverse correlation was observed between SST and Chl-a, confirming upwelling's role in enhancing fertility. These oceanographic conditions directly influenced lemuru abundance, with optimal catch yields occurring at SSTs of 25–26°C. The study concludes that remote sensing of SST and Chl-a is vital for monitoring Potential Fishing Zones (PFZs) and promoting sustainable fisheries management in the Bali Strait amid increasing fishing pressure and climate variability.