Chub mackerel (Scomber japonicus) in the northwest Pacific Ocean is generally divided into the Tsushima Warm Current (TWC) and Pacific stocks, based on habitat and migratory patterns. Since the 1970s, the abundance of the Pacific stock has undergone more extreme fluctuations than the TWC stock, which decreased sharply in the late 1970s and remained at low levels until it began to recover after the 2000s. In this study we focused on the Pacific stock, and analysed the variability in its abundance based on time series data for catch, biomass and recruitment. Sea surface temperature is considered as a major environmental factor that affects the wintering and spawning of chub mackerel. Consequently, we used wintering and spawning ground indices, including the average sea surface temperature (SST), the meridional positional deviance of the 15 °C (MPD15) and 18 °C (MPD18) isotherms and the SST-suitability weighted size of the potential spawning ground (WSSG) in Kuroshio Current waters to analyse the impacts of oceanic environmental conditions in the wintering and spawning grounds on variations in chub mackerel abundance. The wintering and spawning ground indices showed clear decadal variability, with abrupt changes in the late 1970s, the late 1980s and the 2010s. These were correlated with major fluctuations in the abundance of chub mackerel. A combination of correlation and gradient forest analyses showed that the thermal environment in the wintering ground were relatively important predictors of chub mackerel abundance; these predictors (with a 1- or 2-year time lag) may better explain the variations in abundance after the 1970s. Variations in the SST and MPD18 during the spawning period correlated well with the recovery of chub mackerel abundance after the 2000s. Both the Asian Monsoon Index and Southern Oscillation Index correlated with the wintering and spawning ground temperature conditions, indicating that large scale climatic factors have a major influence on variability in temperature in the wintering and spawning grounds of chub mackerel. We conclude that wintering and spawning ground indices for the Kuroshio Current region may be useful for explaining the variations in chub mackerel abundance.

b鱼（Scomber japonicus根据栖息地和迁徙方式，西北太平洋地区通常分为对马暖流（TWC）和太平洋种群。自1970年代以来，太平洋种群的数量比TWC种群经历了更大的极端波动，TWC种群在1970年代后期急剧下降，并一直保持较低水平，直到2000年代以后才开始恢复。在这项研究中，我们重点研究了太平洋种群，并根据渔获量，生物量和募集的时间序列数据分析了其丰度的变异性。海面温度被认为是影响鱼越冬和产卵的主要环境因素。因此，我们使用了越冬和产卵地面指数，包括平均海面温度（SST），15°C（MPD15）和18°C（MPD18）等温线的子午线位置偏差以及黑潮海域潜在产卵场（WSSG）的SST适应性加权大小，以分析冬季海洋环境条件的影响以及on鱼鲭鱼丰度变化的产卵场。越冬和产卵场指数显示出明显的年代际变化，在1970年代末，1980年代末和2010年代发生了突变。这些与鱼的丰度的主要波动有关。相关性和梯度森林分析相结合，表明越冬地的热环境是chu鱼鲭鱼丰度的相对重要的预测因子。这些预测变量（有1年或2年的时滞）可能会更好地解释1970年代后丰度的变化。产卵期SST和MPD18的变化与2000年代后mac鱼鲭鱼丰度的恢复密切相关。亚洲季风指数和南方涛动指数均与越冬和产卵的地温条件相关，表明大规模的气候因素对mac鱼的越冬和产卵地的温度变化具有重要影响。我们得出结论，黑潮当前地区的越冬和产卵地面指数可能有助于解释鱼鲭鱼丰度的变化。表明大型气候因素对鱼的越冬和产卵场的温度变化有重大影响。我们得出结论，黑潮海流地区的越冬和产卵场指数可能有助于解释explaining鱼鲭鱼丰度的变化。表明大型气候因素对鱼的越冬和产卵场的温度变化有重大影响。我们得出结论，黑潮当前地区的越冬和产卵地面指数可能有助于解释鱼鲭鱼丰度的变化。