Assessing the Impact of the 2020 – 2021 La Niña Event on Longtail Tuna (Thunnus tonggol) Migration Patterns Using MaxEnt Modeling

Thunnus tonggol is a primary target in commercial capture fisheries. The Makassar Strait region is defined by diverse physical processes and climatic influences, notably the El Niño Southern Oscillation (ENSO). This study aimed to identify the migration patterns of the longtail tuna that La Niña influenced in 2020/2021 and to forecast fishery regions using the MaxEnt model. The data utilized includes satellite image data of SST, chl-a, SSH, salinity, and current speed, as well as data on the presence of the longtail tuna. During the peak phase of La Niña, the highest CPUE was recorded, with an average of 450kg/ trip. The MaxEnt model suggests that the optimal sea surface temperature for the longtail tuna is between 29 and 30°C. The longtail tuna typically have an ideal chlorophyll-a level of 0 to 0.3mg/ m³. The ideal SSH, salinity, and current velocity values are 0.63 - 0.64m, 33 - 33.5ppt, and 0.1 - 0.3m/ s, respectively. SSH is the key parameter element influencing the longtail tuna distribution. The HSI maps show that the distribution of longtail luna migrates northward at the end of the La Niña period, roughly in coordinates 3 - 5° S and 114 - 118° E.