The objective of the Atlantic Ocean Tropical tuna Tagging Programme (AOTTP) is to contribute to food security and economic growth of the developing Atlantic coastal states by ensuring sustainable management of tropical tuna resources in the Atlantic Ocean. Specifically it will provide evidence-based scientific advice to developing Atlantic coastal states, and other ICCAT Contracting Parties, for them to adopt appropriate conservation and management measures within the framework of the International Commission for the Conservation of Atlantic Tunas (ICCAT). These objectives will be realized by improving the estimation – derived from tag-recapture data – of key parameters for stock assessment, i.e. growth, natural mortality, migrations and stock-structure. AOTTP will tag at least 120,000 tropical tuna fish (mostly bigeye, skipjack and yellowfin) across the Atlantic during 5 years, using a range of conventional and electronic tags. Additionally the Programme will collect, collate and analyze tag-recapture data. All the data collected will be stored in databases maintained by the ICCAT Secretariat and used to improve the estimation of key parameters needed for input to stock assessments. Fisheries scientists from Atlantic coastal states will be trained in tagging, data collection and the use of tag-recapture data in stock-assessment models. Activities of ICCAT AOTTP will include the chartering of professional fishing vessels, liaison with recreational anglers, the deployment of tagging and tag-recovery teams, data collection, scientific interpretation, the development and execution of training courses and the instigation of awareness campaigns to promote tag-recovery. Focal countries will be Ghana, Côte d’Ivoire, Senegal, Republic of South Africa, Venezuela, Trinidad and Tobago, Brazil, EU-Spain (Canaries), EU-Portugal (Azores), Cabo Verde and the USA. Commercial baitboats (also known as pole & line vessels) will be used for most of the tagging work since longline and purse seine gears are known to cause more stress to the fish and increase mortality rates. Since there are no baitboats working off the North American east coast, ICCAT AOTTP will depend on cooperation with recreational game fishers, to tag fish in that area.