Recent work has dealt with the local management of aquatic resources as an alternative to Hardin's (1968) 
tragedy of the commons.
In communities with no formal management of resources, informal ownership of fishing spots or conflicts with outside competitors may determine the basis for future local management. In this study, I analyze the use of aquatic resources by five fishing communities on the Atlantic Forest coast of southeast Brazil: Búzios Island, Puruba, and Picinguaba in São Paulo State, and Jaguanum and Itacuruçá Islands at Sepetiba Bay in Rio de Janeiro State. Informal ownership of fishing spots, used for set gillnet fishing, is regulated by kin ties at Búzios Island. The artisanal fishers of Sepetiba Bay, especially those from Jaguanum Island, have a conflict with Bay intruders, such as the shrimp and herring trawlers. Two coastal communities, Puruba and Picinguaba, have conflicts with fishing regulations from a State Park (Parque Estadual da Serra do Mar),
created in 1977. The transformation of populated areas of the Atlantic Forest to Extractive Reserves might be a way to avoid conflicts with intruders and with governmental agencies, and to involve local populations in management. Kinship rules at Búzios Island and the territorial behavior of fishers at Sepetiba Bay may form a basis for local organization.
Key words territoriality - sea tenure - local management - common property - Atlantic Forest - Extractive Reserve