This report looks at the issue of tax crime in the fisheries sector, including frauds over taxes on profit and earnings, customs duties, VAT and social security, with examples from real cases. These include crimes that rely on features characteristic of the fisheries sector, as well as those seen in other industries. The report discusses aspects of the sector that make it vulnerable to tax crime, including a lack of transparency and difficulty in obtaining beneficial ownership information resulting from the use of offshore companies and the practice of registering vessels under flags of convenience. Strategies used by tax administrations and other authorities to prevent, detect and investigate tax offences are outlined and the report makes recommendations for steps countries can take, alone or in co-operation, to combat these crimes.