A study has revealed that 324 owners control the majority of the global seafood transshipment, with significant contributions from China, Russia, and Greece. These owners operate reefers, which handle a third of the global tuna catch worth £10.4 billion annually. The research, which has identified the owners and their 569 reefers, could lead to improved governance and traceability in the industry. The data, including the operational areas of the reefers, the fishing gear used, and the flags involved, is available online, providing unprecedented transparency and a potential tool for promoting sustainable practices in the fishing industry.