Untangling the network structure for marine litter monitoring governance

Global marine litter monitoring initiatives present information and integration gaps that can be addressed through multi-sectoral collaboration. Social Network Analysis (SNA) helps identify stakeholder roles in accessing, sharing, bridging, and coordinating data for effective monitoring. This study established a theoretical basis and an analytical-operational approach for structuring effective networks for marine litter monitoring. Our research examined a network of 105 stakeholders engaged in a subnational governance arrangement for marine litter monitoring in São Paulo, Brazil. We found that the network allows access to and information-sharing among every actor (i.e., it is non-fragmented), even from different sectors (i.e., it is heterophilic). Although connections are still scarce (i.e., low-density) and decentralized (i.e., low-centralization), bridging and coordinating information relied on central and intermediary actors. SNA findings at the actor level (i.e., degree and betweenness centrality) highlighted the most suitable institutions for these roles, linking otherwise disconnected data producers and addressing critical gaps in data reporting. Our findings suggest that coordinated, centralized network structures may be more effective than denser, highly collaborative structures in the context of litter monitoring governance. These findings contribute to the development of effective, networked actions for marine litter monitoring across diverse scales and contexts, advancing the implementation of Sustainable Development Goal 14, the forthcoming treaty on plastic pollution, and other relevant monitoring initiatives.