Impact of ENSO and IOD Climate Variability on the Dynamics of Bullet Tuna (Auxis rochei) Catches in the Banda Sea

¹ Department of Fisheries Science, Faculty of Marine Science and Fisheries, Hasanuddin University, Perintis Kemerdekaan Km. 10 Street, 90245 South Sulawesi, Makassar, Indonesia
² Faculty of Science and Technology. Universiti Kebangsaan Malaysia. 43600 UKM, Bangi Selangor, Malaysia

^* Corresponding author: mukti@unhas.ac.id

Abstract

The Banda Sea is a tropical marine region in Indonesia with complex oceanographic dynamics and high productivity, serving as a key habitat for pelagic fish such as bullet tuna (Auxis rochei). This study investigates the influence of large-scale climate variability, specifically the El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD), on bullet tuna catch dynamics in 2023. Monthly catch data and oceanographic parameters, including sea surface temperature, chlorophyll-a, and sea surface salinity, were analyzed. Anomalies were calculated using 2008– 2022 climatological data as a baseline. The results indicate that 2023 was influenced by a strong El Niño and positive IOD, significantly affecting ocean conditions. Positive Chl-a anomalies and slightly warmer SSTs in late 2023 were associated with increased catches in November and December. In contrast, negative anomalies in Chl-a and SST early in the year coincided with low catches. Chl-a showed a positive correlation with catch (r = 0.29), indicating the role of primary productivity, while SSS had a moderate negative correlation (r = -0.53), suggesting salinity sensitivity. This study highlights the importance of integrating climate variability into fisheries management and supports using ENSO–IOD indices as predictive tools for sustainable tuna fisheries in eastern Indonesia.