Dynamics of distant water fishing fleets in Southeast Asian countries

Industrial distant-water fishing (DWF) fleets increasingly operate within the Exclusive Economic Zones (EEZs) of developing coastal states, raising critical concerns about ecological impacts, governance capacity, competition, and distributional equity. Yet assessments of DWF impacts frequently rely on aggregate catch metrics, potentially underestimating scale-dependent ecological pressure and institutional vulnerability. Here we develop a two-stage threat framework that integrates reconstructed catch data with a standardized Illegal, Unreported, and Unregulated (IUU) Fishing Index to evaluate DWF-related risk across Southeast Asia. While DWF fleets account for 11% of Southeast Asia’s total reconstructed catch, they concentrate over 70% of landings across five commercially vital taxa and directly compete for 18 species that domestic fleets also rely upon. Composite exposure–governance scores identify Indonesia and the Philippines as being at the highest-risk of threat from DWF, demonstrating that institutional vulnerability can significantly amplify the impact of moderate fishing pressure. Consequently, DWF impacts at the regional scale are highly uneven, remaining moderate in the aggregate but becoming ecologically concentrated and institutionally magnified within governance-constrained EEZs. These findings highlight the importance of integrating species-level ecological overlap with governance capacity when assessing the sustainability of industrial fishing, and underscore the need for transparent access agreements, strengthened monitoring systems, and coordinated regional oversight to reduce sustainability risks.