Vulnerability assessment of maritime chokepoints under global disruptive events: a case study of the COVID-19 pandemic

The COVID-19 pandemic has profoundly impacted the global shipping network, underscoring the key role of maritime chokepoints in the international supply chain. This study integrates fuzzy Bayesian network (BN) and grey relational analysis (GRA) models to evaluate the spatiotemporal evolution of vulnerability across 24 chokepoints during the pandemic, drawing on four dimensions: ship traffic, trade volume, port performance, and epidemic indicators. The outcomes indicate that port congestion and policy interventions during the early stages of the pandemic substantially heightened the vulnerability of maritime chokepoints. Vulnerability reached its peak by the end of 2021 and declined in the latter half of 2022 in line with the broader economic recovery, albeit with pronounced regional disparities. Chokepoints reliant on raw material transportation demonstrated a strong resilience, driven by inelastic demand and geographical irreplaceability. By contrast, those dependent on elastic goods or labor-intensive management were more affected by supply chain disruptions and workforce shortages, leading to pronounced fluctuations in vulnerability. Spatial correlation analysis illustrates that neighboring chokepoints exhibit strong interdependence due to functional complementarity, underscoring a domino effect within the global shipping network.