Impact of future climate change on potential habitats of Pacific saury in Northwest Pacific

Pacific saury (Cololabis saira) is an important commercial fish species in the Northwest Pacific, and its habitat distribution is highly sensitive to climate change. To quantify the changing trends of potential habitats under different climate scenarios and reduce uncertainty in regional fisheries governance and quota allocation for this important high-seas fishery resource, we adopted the fisheries statistical records from Chinese Mainland Pacific saury vessels (2010–2020) and eight marine environmental variables from Bio-ORACLE. A MaxEnt model was used to project future habitat shifts under three Shared Socioeconomic Pathway scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5). The results show that the model achieved high predictive performance (AUC=0.911). Based on variable contributions and jackknife analyses, sea surface temperature, surface primary productivity, and sea surface salinity are the key environmental drivers shaping Pacific saury distribution. By the end of the 21st century, the projected potential habitats under all three scenarios all showed a poleward shift relative to the present, expanding into higher-latitude waters between 50°N and 60°N. In addition, potential habitats expanded in the region of 160°E–180°E and 37°N–40°N. The area of suitable habitat increased overall under SSP1-2.6 and SSP2-4.5, by 0.72%–40.34% and 14.59%–69.80%, respectively. Under SSP5-8.5, suitable habitat area first increased and then decreased, with an overall increase of 4.05%–37.26% during 2020–2070 and a net contraction of 3.67%–21.31% during 2070–2100. This study aims to provide a scientific basis for Pacific saury resource assessment, fishing ground prediction, and regional fisheries management in the northwestern Pacific under future climate change.