Yellowfin tuna (Thunnus albacares) is a cosmopolitan species distributed mainly in the tropical and subtropical oceanic waters of the three oceans. Juvenile yellowfin tuna form mixed schools with skipjack and juvenile bigeye, and are mainly limited to surface waters, while larger fish form schools in surface and sub-surface waters. Although the distinct spawning areas might imply separate stocks, or substantial heterogeneity in the distribution of yellowfin tuna, a single stock for the entire Atlantic is currently assumed (ICCAT 2019).

This assumption is based upon information such as observed transatlantic movements indicated by conventional tagging and longline catch data that indicates yellowfin is distributed continuously throughout the tropical Atlantic Ocean. Movement rates and timing, migratory routes, and local residence times remain uncertain, but recent tagging activities (e.g. AOTTP) offer insights. In addition, some electronic tagging studies in the Atlantic as well as in other oceans suggest that there may be some degree of extended local residence times and/or site fidelity (ICCAT 2019).