Yellowfin tuna (Thunnus albacares) is a highly migratory species that inhabits the epipelagic zone of tropical and subtropical marine waters distributed throughout the three major oceans where it forms large schools, often associated with floating objects (IOTC 2023). 

The evidence of fast and large movements of yellowfin tuna reported by the Regional Tuna Tagging Project-Indian Ocean (RTTP-IO) supports the assumption of a single well-mixed yellowfin tuna population within the Indian Ocean (Murua et al. 2015)(IOTC 2017)(Artetxe-Arrate et al. 2021). It is then assumed to be a single Yellowfin Tuna stock in the Indian Ocean. Nevertheless, genetic differentiations (Dammannagoda et al. 2008), otolith microchemistry nursery areas separation (Artetxe-Arrate et al. 2019), or even stock differentiation based on fisheries data (Nishida 1992), have also been found within the north-western area and between eastern and western areas of the Indian Ocean, suggesting the presence of sub-populations in this region (IOTC 2023).