There is growing concern about the sustainability of fisheries targeting highly migratory fish species worldwide. Tuna and tuna-like species are exploited by multiple nations and the regulation of these stocks are, from a political perspective, exceedingly difficult. Management measures need of a sound scientific knowledge of the stocks and fisheries dynamics. Traditional stock assessment techniques cannot be used in this kind of fisheries, and there is an increasing need for the further development of integrated stock assessment techniques. The aim of the current proposal is the training of the fellow in state-of-the-art stock assessment models and the further development of these models through the inclusion of electronic tagging data, spatial variability of biological parameters, and projections of the models into the future. The south Pacific swordfish, Xiphias gladius, has been chosen as a base case, since assessments of this species are are scheduled to occur in the next 2 years, and due to the role of the EU fleet in the fishery of this resouce. The conclusion of the project would result in a highly trained scientist who can critically review stock assessments of the most important global fish stocks (tuna, swordfish, marlin) that are provided to Regional Fisheries Management Organisations. This would reinforce the position of the applicant as advisor in fisheries management in the framework of the Western and Central Pacific Fisheries Commission. Provision of this level of technical training is highly innovative, provide the EU with the capacity to readily obtain expert advice and will position the EU as a leader is this important area of sustainability sciences. Additionally, the integration of the training objectives and the applicant background would also provide the opportunity of leading some of the developments of the stock assessment models currently in use in tuna RFMOs and, therefore, lead to an independent research line.