Relationship between Fish Catch and Chlorophyll-a in the Java Sea

Lamongan Regency boasts a 47-kilometer coastline, with marine fishing activities primarily concentrated in the waters of the Java Sea, specifically in the Brondong and Paciran Subdistricts. These areas are home to five Fish Landing Bases (Pangkalan Pendaratan Ikan, PPI) cum Fish Auction Places (Tempat Pelelangan Ikan, TPI), starting from the west and extending eastward from Lohgung, Labuhan, Brondong, Kranji, to Weru, bordering Gresik Regency. In 2022, the production of sea-caught fish reached 80,170.34 metric tons. The changing ecosystem within the coastal areas of Lamongan significantly impacts these fishing activities. One observable parameter in this context is the distribution of chlorophyll-a content in the coastal waters. This study employs remote sensing through Terra Modis satellite imagery and the reflectance values Rrs_469, Rrs_547, and Rrs_678. The best response was obtained with Rrs_547 reflectance and the best algorithm model, a second-degree polynomial, represented by y = 44165x² - 156.39x + 0.5164 with an R-squared (R²) value of 0.9180. An exponential model, y = 0.1781e^(308.09x) with an R² value of 0.9101, was also tested. These models were used for mapping and determining the distribution of chlorophyll-a content in the coastal areas of Lamongan.