Sea Surface Temperature Influences Migratory Patterns of the Atlantic Bluefin Tuna ( Thunnus thynnus ) Between the Atlantic Ocean and the Mediterranean Sea

ABSTRACT Oceanographic variability plays a critical role in shaping the migratory behavior of the Atlantic bluefin tuna ( Thunnus thynnus ). This study investigates the thermal preferences of individuals migrating through the Strait of Gibraltar and the Gulf of Cádiz during pre‐ and post‐spawning movements. Comparing data measured from electronic tags and satellite‐derived sea surface temperature (SST) fields, we identified distinct SST preferred ranges associated with each migratory phase: 17.4°C–19.3°C inbound to the Mediterranean and 18.4°C–22°C outbound to the Atlantic. Based on these preferences, we developed a SST adequacy index reflecting thermal suitability, which we applied to 13 years of high‐resolution SST satellite data (2010–2022). Spatial and temporal patterns of SST adequacy were then classified using Self‐Organizing Maps, revealing dynamic hotspots of thermal suitability along migratory corridors. Our findings highlight the nonrandom, environmentally modulated nature of ABFT migrations and offer a framework to advance towards climate informed fisheries assessment, a current request of the International Commission for the Conservation of Atlantic Tunas.