Abstract: This study aims to reveal the differences in habitat depth layers of North Pacific albacore tuna and their response patterns to environmental factors. By integrating published literature and catch depth data obtained from offshore experiments conducted in 2023, a Gamma distribution was used to fit the probability distribution of albacore tuna habitat depths. Historical CPUE data from 1964 to 2019 were employed to represent population intensity in the North Pacific region. Combined with marine environmental data from the Copernicus Marine Environment Monitoring Service (CMEMS), including longitude, latitude, temperature, salinity, dissolved oxygen, and chlorophyll-a concentration, and using a weighted resampling approach, habitat depth samples of albacore tuna matched to environmental grids were generated. A boosted regression tree (BRT) model was then constructed to quantitatively analyze the response relationships between habitat depth layers and environmental factors, and to predict habitat depths of North Pacific albacore tuna along latitudinal transects at 0°, 10°, 20°, and 30° N. The Gamma distribution fitting results indicate that the habitat depths of albacore tuna can be classified into two types: a shallow-layer type and a deep-layer type. The mean habitat depth of the shallow type ranged from 88.3 to 117.9 m, whereas that of the deep type ranged from 193.5 to 259.9 m. The BRT model results show that latitude was the most influential factor (relative importance ≈ 0.47), followed by dissolved oxygen (0.15), longitude (0.12), temperature (0.10), salinity (0.10), and chlorophyll-a (0.09). Partial dependence analyses demonstrate that temperature and dissolved oxygen exert significant nonlinear effects on albacore tuna habitat depths, and that habitat depth gradually becomes shallower with increasing chlorophyll-a concentration. Predictions along latitudinal transects reveal that habitat depths near 0° N are generally deeper and relatively stable (approximately 200 m), whereas they become markedly shallower at higher latitudes around 30° N (less than 150 m). Pronounced latitudinal gradients exist in the habitat depths of North Pacific albacore tuna, primarily driven by the combined effects of environmental factors such as temperature, dissolved oxygen, salinity, and chlorophyll-a. The BRT modeling framework based on a Gamma probability distribution and CPUE-weighted resampling effectively characterizes the relationships between albacore tuna habitat depth distributions and environmental variables under conditions of limited catch data, providing methodological support for improving longline fishing efficiency and promoting the sustainable utilization of distant-water fishery resources.