Effects of western boundary currents and sea surface temperature anomalies on interannual variability of chub mackerel abundance in the Northwest Pacific

The abundance of chub mackerel (Scomber japonicus) in the Northwest Pacific has undergone significant changes in recent decades. To investigate the long-term and short-term impacts of environmental factors on the abundance of chub mackerel, Kuroshio volume transport in summer and winter, the Oyashio area, the Oyashio southern limit, and the Sea Surface Temperature Anomaly (SSTA), were selected to construct the ARDL-ECM model based on the Autoregression Distributed Lag (ARDL) method for 3 age groups with resource abundance as the response variable. The results showed that in short term effects there is a positive correlation between Kuroshio intensity and the chub mackerel abundance in winter, but a negative correlation in summer. Oyashio area can impact the fish abundance under 2 years old significantly (p < 0.001) and the change of Oyashio sourth limit only has a significant impact on the abundance of 0-age fish (p < 0.001). In the long-term relationship, Kuroshio significantly influences the abundance of fish aged 3 years and older (p < 0.001). SSTA had a significant impact on the abundance of all 3 age groups (p < 0.05), while Oyashio area may influence the fish abundance under 2 years old (p < 0.05). Furthermore, Oyashio south limit was found to affect the abundance of fish aged over 1 year (p < 0.01). SSTA can increase the abundance in both short term (p < 0.001) and long term (p < 0.001).The findings of this research may enhance our understanding of the variations in chub mackerel abundance in the Northwest Pacific.