Past and future anthropogenic impacts on Atlantic bluefin tuna through the eyes of demographic and adaptation analyses on range-wide whole genomes

Atlantic bluefin tuna (Thunnus thynnus) have been commercially exploited for centuries, yet historical baselines used in fisheries management may underestimate the extent of past declines. Recent genomic analyses suggest that ABFT underwent a demographic decline as early as 1900, long before modern fisheries records indicate. This decline coincided with a reduction in genome-wide diversity, suggesting potential long-term consequences for population resilience. High coverage resequencing of 45 modern and 45 ancient specimens (dating back to 3000 BC) collected across the species range, from the Mediterranean to the Gulf of Mexico, was undertaken to improve resolution in detecting genetic erosion and adaptive change, capitalizing the recently released chromosome level and annotated Thunnus thynnus genome. By integrating genomic, environmental and fisheries data, this research will provide a deeper understanding of ABFT population structure, historical demography and resilience. This knowledge can improve stock assessments, refine recovery targets and inform long-term conservation strategies, ensuring that management decisions take into account both historical and current population dynamics.