Climate-driven distribution shifts of Japanese flying squid (Todarodes pacificus) and its implication for fisheries

Climate change is reshaping marine ecosystems worldwide, yet its effects on some oceanic squid species remain understudied despite their ecological and economic importance. The Japanese flying squid, Todarodes pacificus , a key neritic-oceanic species in the Northwest Pacific, has shown regionally divergent catch trends in recent decades. While such patterns may be influenced by multiple factors, one of which is whether climate change has altered the species suitable habitat and distribution. Therefore, this study, using ensemble species distribution model (SDM) calibrated with presence-only data and environmental variables, assessed whether climate-drive habitat shifts explain divergent spatial patterns. We applied eleven SDM algorithms and selected high-performing models, then ensembled the selected models to project the species distribution under current conditions and future climate scenarios (SSP126, SSP245, SSP585) across three timeframes (2030 s, 2060 s, 2090 s). Sea surface salinity and temperature were the strongest determinants of habitat suitability, with the squid favoring waters below ~33.5 psu and temperatures between ~11–22 °C. Projections consistently showed a marked contraction of suitable habitat, particularly in the Sea of Japan and the Pacific coast around Japan, with limited poleward expansion. Our results highlight the East China Sea and Yellow Sea as potential climate refugia of T. pacificus . Furthermore, it underscores the importance of adaptive, region-specific fisheries management in a warming ocean and demonstrate its implication for fisheries to enhance resilience strategies for mobile marine species under global change.