Modeling Mackerel Tuna (Euthynnus affinis) Habitat in Southern Coast of Java: Influence of Seasonal Upwelling and Negative IOD

We used fishery catch data from Cilacap Fishing Port and Copernicus set in July 2016-December 2017 to investigate the impacts of Indian Ocean Dipole (IOD) on upwelling mackerel tuna distribution southern coast Java. This study implemented a Generalized Additive Model (GAM) for habitat prediction waters. The present showed that extreme negative IOD 2016 caused weaker southeasterly wind even reversal northwesterly wind, as seen off Sumatra September 2016. situation produced vertically mixed layer thickening no during southeast monsoon event 2016, consequently resulted warmer temperature fewer Chlorophyll-a (Chl-a) compared 2017. production significantly dropped rose 2017, particularly event. high Habitat Suitability Index (HSI) was found Central Java expanded bigger August decreased During HSI covered only less area region disappeared indicates oceanographic factor is consistent with probability tuna.