Abstract
<title>Abstract</title> <p> Systems thinking offers a powerful way to address complex social–ecological challenges, yet many approaches remain difficult to implement in data-poor, participatory management settings. We developed and applied a practical decision-support framework that integrates participatory causal loop diagramming, stochastic token diffusion modeling, and network centrality analysis. We applied the framework to small-scale octopus ( <italic>Octopus mimus</italic> ) fisheries in Peru and Chile, where sustainability is challenged by data limitations, informal harvesting, market pressures, and compliance. Through a series of participatory workshops, stakeholders co-developed causal maps, identified shared sustainability goals, evaluated potential interventions, and interpreted network-based analyses. Across both fisheries, stakeholders converged on octopus abundance and fisher compliance as the primary sustainability goals. Token diffusion simulations indicated that traceability interventions produced the strongest and most rapid improvements in fisher compliance, whereas octopus abundance responded through multiple intervention pathways. Network centrality analyses identified several practical monitoring candidates, including landing price, fishing effort, total landings, debt, fishers’ concern for sustainability, and processing quality. The analyses also revealed country-specific dynamics, including stronger propagation of intervention effects in Chile and distinct leverage points associated with product stockpiling. Our findings demonstrate how integrating participatory systems mapping with lightweight network analyses can help stakeholders evaluate interventions, identify monitoring priorities, and support adaptive decision-making in data-poor fisheries. </p>