Marine fish are a precious natural resource and their exploitation for nutrition and income is deeply embedded in human culture. However, massive fi shing activity, both legal and illegal, has had dramatic impacts, and poses a threat to the future of the fi sheries sector. Virtually 70% of the world?s fish stocks are fully exploited, overexploited or in a state of collapse. European waters are not exempt, with almost 90% of fi sh stocks being overexploited. IUU fi shing (Illegal, Unregulated and Unreported fishing) is vastly contributing to this situation. In 2010, the value of IUU fi shing amounted to 10-20 billion Euros annually, with at least 1.1 billion Euros worth of illegal fish being imported into the European Union every year. Furthermore, fraud along the supply chain with fish products sold under false labels, such as low-cost catfish as valuable sole or cod fillets, poses additional challenges. These illegal activities have severe adverse effects, as they undermine stainable fisheries, cause destruction of marine ecosystems, obstruct socioeconomic development, and impede consumer information and protection. A number of nations have developed strategies to deter and fi ght illegal fishing activities, and numerous countries have adopted the International Plan of Action to prevent, deter and eliminate IUU Fishing (IPOAIUU), that has been developed in 2001 within the framework of the Code of Conduct for Responsible Fisheries by the FAO. The European Union has recently taken further initiatives and developped two major and complementing legal instruments: in January 2010, Council regulation (EC) No 1005/2008 (1), - the `IUU regulation?, entered into force, and in November 2009, Council regulation (EC) No 1224/2009 (2) - the new Control regulation- establishing a Community control system was adopted and is in the process of being implemented. Both regulations place emphasis on detailed catch documentation and traceability for fishery products `from ocean to fork?, that is, covering all stages of the supply chain from catch, to landing, transport, processing, and the markets. Traceability is generally acknowledged as being a highly powerful tool in support of monitoring, control and enforcement in the fisheries sector. However, currently it is mainly based on certifi cates accompanying goods, and labelling of products, both measures which are vulnerable to falsification. So how can inspectors and control and enforcement authorities validate and authenticate the information provided by documentation? How can the industry assure that the fi sh it is processing and selling is what it is supposed to be, e.g. the correct species and fi shed legally? And fi nally how can the consumer be certain that the information provided for fi sh products is correct? A system is needed to effectively trace fi sh products throughout the food supply chain that is supported by independent control measures. Likewise control and enforcement authorities need effi cient analytical tools for generating evidence in court trials. Molecular techniques based on genetics, genomics and chemistry, and embedded in a forensic framework, have great potential in this respect. This JRC report describes available molecular techniques and technologies and discusses how these can be used for traceability and in support of fi sheries control and enforcement. The report provides examples of cases where molecular techniques were employed to reveal fi sheries fraud and to generate evidence in court cases. These examples clearly demonstrate the feasibility and operational potential of the techniques in real-world contexts. Furthermore, the report explores possibilities for translating forensic genetics and chemistry into a European fi sheries control and enforcement framework, within the context of the current EU policies and legislation.