Social-ecological dynamics in management systems: Investigating a coastal lagoon fishery in southern Brazil

This dissertation is about dynamics of social-ecological linkages. In order to contribute to the efforts of sustainable natural resources and environmental management, the research focuses on the history of the Ibiraquera Lagoon fishery management system in Southern Brazil.; The Lagoon is a brackish water system seasonally connected to the Atlantic Ocean. Pink shrimp (Farfantepenaeus paulensis and F. brasiliensis) fishing with cast-nets is the major fishing activity. Mullet and blue crabs are also important fishing resources. Legally the Lagoon is a state-property but over the past five decades it has been managed under different property systems.; The study shows that resource users may provide a valuable set of information about resources and ecosystem dynamics. Moreover, local management practices may provide insightful information about the concerns, values, and ethics of resource users.; In analyzing resilience of the management system through cycles of change, the study points out five key factors that strengthen resilience. These are: strong institutions, good cross-scale communication, political space for experimentation, equity in resource access, and the use of memory and ecological knowledge as a source of innovation and novelty. In addition, four key factors that weaken resilience were detected. They include: the breakdown of local institutions, rapid technological change, rapid socio-economic change, and institutional instability across political scales.; Socio-economic incentives and constraints that affected the Lagoon management system included: new values and ideas brought by outsiders, new economic opportunities created by outsiders, increase in market demand for fishing products, community's infrastructure improvements, development projects, and technological innovations.; The study shows that institutional instability at higher political levels, the great diversity of ineffective management agencies, and the lack of coordination among government agencies from different levels and sectors result in stakeholder conflicts, environmental degradation and resource overexploitation at the Ibiraquera Lagoon and the surrounding area.; This research indicates that the concept of extractive reserves can be a useful mechanism leading to sustainability. However, property-rights instruments, such as extractive reserves, are a necessary but not a sufficient condition to achieve sustainability. Several policy instruments, including market-based ones, need to be used jointly. In this context, I discuss an alternative policy for the Ibiraquera Lagoon consisting of the establishment of an extractive reserve to restrict the number of fishers, and a combination of regulations and a licensing system to operate such a reserve. In addition, I recommend the creation of a co-management Forum representing the stakeholders to manage the Lagoon. (Abstract shortened by UMI.)...