Abstract

The Humboldt current system (HCS) sustains the highest global fishing catch for individual species. It is susceptible to interannual and decadal climate variability, which cause species-, community-, and ecosystem-level changes. Therefore, systematically exploring changes in the fishery ecosystem structure driven by climate variability is beneficial for fishery management in the region. In this study, a combination of large-scale climate, regional environmental, and functional groups catch data was used to detect regime shifts in the fishery ecosystem structure within the HCS and to investigate the possible impact mechanisms of climate variability. The results indicated that obvious decadal changes in the fishery ecosystem structure within the HCS align with inferred regime shifts in the early to mid-1970s, mid-1980s, and late 1990s. These shifts corresponded well to climate and regional environment regime shifts during these periods. Among the climate and environmental variables studied, the first and third principal components of climate index and the first principal component of regional environmental variables showed higher ecological importance for fishery ecosystem structure variations within the HCS. This suggest that fluctuations in the Aleutian Low and El Niño–Southern Oscillation significantly affected the regional environment, characterized by heat and wind speed, and consequently induced alterations in the fishery ecosystem structure. This study contributes to holistic understanding of climate-driven changes in the fishery ecosystem structure within the HCS, providing a robust foundation for ecosystem-based fisheries management.