Projected Decline in Arctic and Subarctic Commercial Fish Catches: Insights from Reconstructed Ocean Biogeochemical Modeling

Climate change is driving significant temperature increases in the Arctic region—over four times the global average—impacting fish populations that are highly sensitive to thermal variations. Elevated water temperatures enhance the metabolic oxygen demands of fish while simultaneously decreasing oxygen solubility in seawater. This dual effect may force fish to migrate to more favorable habitats or face higher mortality rates. While previous studies have primarily focused on the relationship between water temperature and fish catches, the influence of dissolved oxygen has remained understudied due to limited data availability. In this study, we utilized reconstructed ocean biogeochemical data from the Geophysical Fluid Dynamics Laboratory Earth System Model (GFDL-ESM2) covering the Arctic and Subarctic Exclusive Economic Zones (EEZs) from 1970 to 2017 to calculate a metabolic index that integrates both temperature and dissolved oxygen levels. Our findings demonstrate a strong correlation between the metabolic index and the catches of large demersal fish species. Permutation importance analysis revealed that dissolved oxygen often plays a more critical role than temperature in determining fish catches across numerous regions. Additionally, fish catches in subsurface areas with higher dissolved oxygen importance exhibited longer lead times in predictability, likely due to the prolonged persistence of biogeochemical conditions. Projecting into the future under various Shared Socioeconomic Pathway (SSP) scenarios up to 2100, our results consistently indicate a continued decline in fish catches across all scenarios. These outcomes highlight the urgent need to incorporate the physiological characteristics of fish into sustainable fisheries management practices to mitigate the adverse effects of changing ocean conditions in the Arctic and Subarctic regions.