Abstract: Ommastrephes bartramii, a short-lived cephalopod species, is highly sensitive to environmental variability. The Northwestern Pacific Ocean serves as its primary habitat, where frequent marine heatwaves (MHWs) significantly impact population dynamics. However, the mechanisms underlying these impacts remain poorly understood. The study aims to elucidate the impact mechanisms of MHWs on the resource abundance and spatiotemporal distribution of O. bartramii in the Northwestern Pacific Ocean. The study utilizes gridded fishery and environmental data spanning May to November from 1995 to 2020 across O. bartramii fishing grounds in the Northwest Pacific Ocean. A seasonal dynamic threshold method was employed to identify MHW events, quantify cumulative intensity, and distinguish between MHW and non-MHW periods. Following precise spatiotemporal alignment of samples, variance inflation factor analysis was conducted to screen independent environmental variables. A boosted regression tree (BRT) model was developed to analyze the impact mechanisms of MHWs and environmental factors on O. bartramii abundance and distribution, and to reveal core habitats and their spatiotemporal dynamics. The cumulative intensity exhibited significant intermonth variability, showing a strong positive correlation with O. bartramii resource abundance (r = 0.858, p = 0.013). The BRT model revealed that cumulative intensity served as an ecological indicator of O. bartramii resource abundance, accounting for 3.427% of the model's relative importance. Response curves demonstrated significantly higher O. bartramii resource abundance under MHW conditions, with a slight increasing trend under higher cumulative intensity. Model results identified high-abundance regions within 42 °-45 °N、150 °-175 °E, revealing significant spatiotemporal coupling between O. bartramii abundance and cumulative intensity from May to November. The occurrence of MHWs is more conducive to the aggregation of O. bartramii, promoting the formation of high-abundance fishing grounds. Given the scarcity of biological data, the analytical framework proposed in this study provides a generalizable approach for investigating MHW-marine organism interactions. These findings offer scientific support for O. bartramii stock assessment and sustainable fishery management strategies.