Vezo migrant fishers have played a key role in shaping the seascape and resource use practices in the Southwest of Madagascar. As a population relying mainly on fishing for its livelihood, Vezo people have struggled to maintain their livelihood in the face of resource depletion. They migrate seasonally or long term from their home region on the southwest coast to marine frontiers further north such as the Barren Isles, a remote archipelago in the west of Madagascar. Exploiting sea cucumber and sharks for the global market involves economic and ritual practices that they have maintained in their journeys and constitute their identities as migrant fishers. Within a context of increasing commercialization and depletion of small-scale fisheries, various conservation initiatives have taken place within the migration route of the Vezo including the establishment of Madagascar's largest marine protected area in the Barren Isles. This article argues that migrant fishers have managed to gain, maintain and control access to marine resources, both by performing ancestral rituals by which newcomers attach themselves to ecological niches, and also by mobilizing an environmentalist identity narrative promoted by the Malagasy government and international NGOs. In this way, Vezo migrant fishers have become key actors in the management of marine resources while maintaining their ancestral practices. This is an important argument discussing the role of local identity narratives in the political economy of global resource appropriation and shows how migrant fishers fit in the contemporary seascapes.