Climate models drive variation in projections of species distribution on the Grand Banks of Newfoundland

Species Distribution Models (SDMs) are tools for understanding climate-induced habitat changes, yet their outcomes depend heavily on climate model selection. This study compares biomass projections for three key species on the Grand Banks of Newfoundland that are known to be sensitive to warming—snow crab, yellowtail flounder, and Atlantic cod. We use Earth system models (GFDL-ESM4, IPSL-CM6A-LR) and a regional ocean model system (Atlantic Climate Model (ACM)) under varying climate change emissions scenarios to assess long-term biomass trends and distributional shifts driven by future ocean warming on the Grand Banks. Projections indicate declining biomass for snow crab and yellowtail flounder with rising temperatures, whereas Atlantic cod is anticipated to exhibit biomass gains, particularly in the southern Grand Banks. Variations in biomass projections among climate models were noticeable, with IPSL forecasting the most drastic decline. ACM and GFDL biomass projections were more similar to each other than GFDL and IPSL projections, likely because ACM was downscaled from GFDL. Differences between GFDL and ACM likely arise from the coarse spatial resolution of ESMs, leading to insufficient resolution of the bathymetry and incorrect current patterns, in turn affecting the bottom temperature field. These findings underscore the important role of climate model selection in SDM-derived biomass projections. We partitioned uncertainty by source and found that the relative contribution of variability by component changes by species. As temperatures continue to rise, the urgency of implementing adaptive management strategies to minimize impacts on Newfoundland and Labrador fisheries becomes increasingly evident. SDM outputs can aid in strategic decision making, providing valuable insights for medium and long-term planning in fisheries management.