Largehead hairtail is an important fish species in the China Seas, characterized by wide distribution, extensive migration, long spawning period, and high economic value. Despite continued overexploitation, its catch trend is increasing which could due to improved recruitment resulting from alterations in early life history. To understand the variability of early growth traits in largehead hairtail, we examined the linkages between early growth and environmental variables at both spatial and temporal scales. By employing otolith microstructure and gradient forest analysis on samples collected from the Bohai Sea, Yellow Sea, and the East China Sea, we found distinct early growth patterns and Age at First Maturity (AFM) for each population at different latitudes. Compared to low latitudes, high latitudes exhibit greater fluctuation in daily increment and earlier sexual maturity. Furthermore, the analysis reveals that temperature, salinity, and mixed layer depth are influential environmental variables with sea bottom temperature being the most significant factor. The study emphasizes the importance of understanding reproductive processes and early growth of largehead hairtail in relation to environmental variables for sustainable management and utilization in the over-exploited China Seas.

Trichiurus japonicus,early life history,latitudinal diference,climate change