Participatory One Health network modelling of climate-sensitive Vibrio and antimicrobial resistance risks in the Tasmanian oyster supply chain.

Climate change is reshaping the ecology of foodborne pathogens, with implications for human, animal, and environmental health. In Australia, emerging risks associated with Vibrio parahaemolyticus and antimicrobial resistance (AMR) in aquaculture threaten seafood safety. Integrative, One Health-aligned risk assessments remain limited. We aimed to characterise climate-sensitive dynamics of Vibrio and AMR risks in the Tasmanian oyster supply chain using a participatory systems modelling approach. We applied qualitative network modelling (QNM) to represent interactions across environmental, microbial, industry, and policy domains. The initial model was developed from a targeted literature synthesis and refined through expert elicitation workshops. The final model comprised of 25 nodes and 47 directional linkages and was analysed using QPress (R) to simulate responses to climate-related perturbations. Scenarios represented increases in air temperature, water temperature, extreme rainfall, and cross-sector collaboration and food safety awareness. The proportion of total simulations showing a positive, negative or no change were recorded for each node. Increasing air temperature amplified post-harvest Vibrio risks along the cold chain, increased consumer mishandling, and produced the highest propensity for V. parahaemolyticus outbreaks. Both air and water temperature increased Vibrio abundance in seawater and accumulation in oysters, with stronger downstream effects under air-temperature stress. Extreme rainfall most strongly affected AMR-related variables via pollution pathways; however, interpretation was limited due to knowledge gaps, indicating priorities for future empirical work. Combined climate perturbations acted additively rather than synergistically and were largely dominated by air temperature effects, reinforcing known vulnerabilities. In contrast, increasing cross-sector collaboration and food safety awareness generated favourable system-wide responses, including improvements in human health and oyster demand, alongside reductions in temperature abuse and consumer mishandling. Participatory systems modelling can operationalise One Health in climate-sensitive food systems. We identified key variables and feedbacks influencing Vibrio infection and AMR risks along the oyster supply chain, leverage points, and enabled exploration of interventions in a data-limited context. Findings emphasise the importance of cross-sector collaboration and targeted regulation to mitigate climate-driven Vibrio and AMR risks. This integrative approach offers a scalable decision-support tool for supply chain resilience, public health preparedness and climate adaptation planning.