Variability of chlorophyll-a concentration relation to fish catch of Indian mackerel in West Halmahera waters

The presence of chlorophyll-a is an indicator of water fertility, where the high chlorophyll-a content will be followed by the presence of zooplankton which will then affect other aquatic organisms that form the food chain. The interaction of chlorophyll-a concentration on the presence of mackerel in West Halmahera waters is unknown, so this study was carried out with the aim of examining the relationship between chlorophyll-a concentration in West Halmahera waters and mackerel catch. The use of experimental fishing methods from May to July 2020 and non-linear regression analysis and Generalized Additive Model (GAM) are expected to provide an overview of the relationship between the two research variables. The results showed that the distribution of Indian Mackerel was more in coastal areas with a chlorophyll-a concentration distribution of 0.18 - 0.39 mg/m3 which played a major role in determining the variability of the quantitative distribution of mackerel (α < 0.05) and positively correlated with a value of r = 0.819 and these results supported by predictions using GAM, where the potential fishing area for mackerel in West Halmahera waters is at a chlorophyll-a concentration value of aboutb 0.2 - 0.4 mg/m3.