Abstract: The Amundsen Sea, situated in the western Antarctic region, is recognized as one of the marine ecosystems changing most rapidly under the influence of climate change. Characterized by extensive sea ice cover, dynamic coastal polynyas, and high seasonal primary productivity, this region provides critical habitats for two dominant euphausiid species: Euphausia superba and Euphausia crystallorophias. This review comprehensively summarizes current knowledge on the spatial distribution, environmental drivers, and habitat preferences of krill in the Amundsen Sea, with particular emphasis on the combined effects of sea ice dynamics, primary production, water temperature, and ocean circulation. Our synthesis indicates that krill distribution patterns exhibit pronounced regional and seasonal variability, shaped by multiple interacting environmental factors. Sea ice, in particular, plays a central role by regulating breeding success and larval survival through its timing of retreat, thickness, and spatial extent. The retreat of seasonal sea ice initiates phytoplankton blooms that provide critical food for krill, especially during early life stages. Meanwhile, hydrodynamic processes such as coastal currents, gyres, and mesoscale eddies modulate krill transport, aggregation, and retention in suitable habitats, reinforcing their spatial patchiness and influencing predator–prey dynamics. Despite these advances, several knowledge gaps remain. Existing ecological models often rely on simplified linear assumptions or single-variable analyses, thereby lacking the capacity to capture complex interactions and feedbacks between environmental factors. Moreover, they rarely incorporate biological processes such as life-history stage transitions, diel vertical migration, or phenological shifts, which are crucial for accurate projections under changing climatic conditions. Limited availability of long-term observational data, particularly in winter and transitional seasons, further restricts our ability to evaluate interannual variability and climate-driven habitat shifts. Future research must focus on integrative approaches, including deployment of long-term ecological monitoring stations, development of high-resolution coupled physical–biogeochemical models, and interdisciplinary collaborations that bridge observational, experimental, and modeling frameworks. Understanding the synergistic and nonlinear interactions between multiple environmental drivers will be key to predicting krill population dynamics, assessing ecosystem resilience, and informing sustainable management of polar marine resources.

Key words: Amundsen Sea,  Antarctic krill,  Euphausia crystallorophias,  environmental drivers,  ecological modeling