In the last three decades, sea ice loss and climate warming have fundamentally altered the Arctic marine ecosystem, including the biogeographical distribution of zooplankton. However, whether certain keystone organisms, such as Calanoid copepods, can establish populations in the low-productivity Central Arctic Ocean has been widely debated. By integrating observational evidence and modeling results of 1993-2022, we demonstrate that the probabilities of two endemic mesozooplankton species, Calanus glacialis and C. hyperboreus, completing their life cycles along the fringe of Central Arctic basins significantly increase along with retreating marginal ice zones. Our results indicate that thinning sea ice and prolonging growth seasons create favorable conditions for copepods’ development and induce their poleward migration. Accelerated surface current, partially driven by recent sea ice decline, further enhances poleward expanding copepod ecological niches. These findings highlight that the changing Arctic's physical and biological drivers associated with sea ice loss profoundly impact the planktonic biogeography and have potential cascading effects on the marine food web and biogeochemical cycling. 

zooplankton, sea ice, surface current, life history, Arctic Ocean