The shortfin mako shark Isurus oxyrinchus is an iconic species that is generally regarded as the fastest swimming shark reaching speeds over 30 mph. It is a warm-bodied, highly active shark with a circumglobal distribution in tropical and warm-temperate seas of all oceans. Shortfin makos are taken by high seas fisheries and high demand for fins and its good-quality meat over several decades have been linked to dramatic declines in abundance. Very little is known about its ecology, including movements, habitat preferences, population structure, even though this basic information is urgently needed for improving the accuracy of relative abundance estimates crucial for stock assessments.This project will provide the first long-term trackings of shortfin mako shark movements and space utilisation in the central North Atlantic Ocean. Our aim is to determine annual movements, migratory routes and habitat use of shortfin makos, and to quantify overlap with areas exploited by commercial longlining fleets. Our objective is to identify and map the critical habitat of shortfin makos in the North Atlantic where it interacts with fisheries to highlight high-risk areas for this species that are relevant to management and conservation assessments. The project draws on two new opportunities. First, long-term trackings will be made possible with our newly developed deep-dive-resistant satellite transmitters, which mitigate the damaging effects on conventional tags of repetitive deep dives (to 2 km depth) by makos that we discovered recently. Second, a unique database of Spanish and Portuguese longlining fleet GPS-tracks is available to us to analyse for the first time in relation to mako movements. Together, these will allow mako migrations, habitat preferences and overlap with fishing activities to be quantified to identify critical habitat and conservation targets for this species across its entire range in the North Atlantic.