This paper presents an ethnographic case study of the design and revision of a decentralized marine management scheme implemented on the island of Moorea, French Polynesia named Plan de Gestion de l’Espace Maritime (PGEM). Drawing on an analysis of over 50 consultative workshops and meetings, held from 2018 to 2021 during the PGEM revision, we document the materials, discourses, and practices local stakeholders (e.g., fishers, cultural and environmental activists, government staff, and scientists) combine to build their interpretations of PGEM success or failure. We examine the diversity of domains these interpretations draw from (ecology, marine livelihoods, culture, religion, and politics) and how they are put into practice in people’s engagement with—or resistance to—the local marine management and governance design. Our results highlight how the controversies around the revision of Moorea’s PGEM overflowed the boundaries of ecology as construed by scientific experts. Stakeholders interpreted “marine resource management” as something well beyond just “marine resources” to include politics, identity, Polynesian cosmology, and livelihoods. Our findings provide generalizable patterns for understanding how natural-resource management policies are received and repurposed by local actors.