Moored fish aggregating devices (MFADs) are used by small-scale fishers to access fish species difficult to harvest in large numbers. In the case of Guadeloupe (Caribbean area), the use of MFADs has increased considerably and this is causing congestion in these fishing areas and creating conflict between fishers. The aim of this article is to understand how informal fishing territories around the La Desirade Island were established and examine these territories through the lens of economic defendability theory. Results of semistructured interviews show that MFAD fishers display territoriality along MFAD tract lines forming quasi-privatized areas. Territoriality in this article is based on the following factors: the type of targeted resources, the cost of harvesting, the defending of territories, and the acknowledgment of territories by the fishing community. Conflicts and utilization of MFADs (overcapacity) have raised an opportunity to create co-managed legalized territorial use rights for fisheries.