Takahashi, B. & van Duijn, A. P. 2012. Operationalizing fisheries co-management: Lessons learned from lagoon fisheries co-management in Thua Thien Hue Province, Viet Nam. FAO Regional Office for Asia and the Pacific, Bangkok. RAP Publication 2012/02, 131 pp.   natural resources is of the utmost importance for national governments to achieve their resource management objectives. This is especially the case in the absence of well-defined property rights, or where the rights to the resources are vested with a government agency that is not fully able to enforce regulations regarding access to and withdrawal of natural resources. In this situation government agency can choose to allow an identifiable community of interdependent users to comanage natural resources. In such a communal property regime, the most relevant day-to-day or operational-level property rights are "access" and "withdrawal" rights. However, communities may also have a more extensive set of rights that authorizes their participation in defining operationallevel rights such as management and exclusion. Worldwide, this co-management of natural resources is making a positive contribution to the management of increasingly scarce natural resources, by enhancing stakeholders involvement. In Viet Nam, fisheries resources are de jure state property, but de facto common pool resources. Management information on the wide variety of target species is often lacking and difficult and expensive to collect. This situation is further complicated by the small-scale nature of coastal fisheries with a wide diversity of gear and landing sites. As the financial burden of monitoring, surveillance and control measures required to implement management measures through top-down control is too high, government authorities increasingly view participation of resource users as a necessary element of the fisheries management system. As a consequence, the government of Viet Nam is looking for suitable alternatives to achieve its fisheries resource management objectives. At the national level this has resulted in the establishment of the Viet Nam Fisheries Society (VINAFIS) with branches at provincial level. The Integrated Management of Lagoon Activities in Thua Thien Hue Province Project (IMOLA) is a trust-fund project started in August 2005, funded by the Italian and Vietnamese governments. The project is aimed at assisting the Thua Thien Hue Province to promote the livelihoods of local fisherfolk through the sound and sustainable management of natural resources in the Tam Giang– Cau Hai Lagoon, which is the largest lagoon system in Southeast Asia. As both the population and the economy of Thua Thien Hue Province are growing, the Tam Giang–Cau Hai Lagoon ecosystem is coming under increasing pressure. Overexploitation of fisheries resources by capture fisheries and encroachment on critical habitats by aquaculture ponds are key contributors to the deterioration of fisheries resources. IMOLA supports the implementation of Decision 4260/2005/QD-UBND, in which the Provincial People's Committee delegates power to the district authority to allocate fishing rights to fisheries associations (including some forms of aquaculture) at the grassroots level. This is done through the establishment and strengthening of fisheries associations and the development of an effective co-management mechanism. This publication aims at enhanced understanding of the role of the national government in promoting fisheries co-management in Viet Nam and its conclusions can be used more widely as a source of advice for and guidance to those in the region or further afield who are involved in fisheries resource management. Finally, the report serves as an advocacy tool for implementing fisheries co-management approaches.