HABITAT DISTRIBUTION CHARACTERISTICS AND KEY INFLUENCING FACTORS OF ACIPENSER DABRYANUS JUVENILES IN LUZHOU RIVER SECTION OF THE YANGTZE RIVER

The Yangtze sturgeon (<italic>Acipenser dabryanus</italic>), an endemic rare fish of the Yangtze River Basin, relies on specific juvenile habitat distributions and key environmental factors for population restoration. Using 2023 monitoring data from the Luzhou section of the upper Yangtze River, we analyzed the spatial and temporal patterns in <italic>A. dabryanus</italic> juvenile resource density and employed a generalized additivity model (GAM) to identify critical environmental factors influencing their habitat distribution, focusing on areas with artificially stocked juveniles. The results showed that there were significant temporal and spatial variations in <italic>A. dabryanus</italic> juvenile density within the Luzhou section. Temporally, summer densities were significantly higher than autumn values (<italic>P</italic>&lt;0.05). Spatially, among the eight investigated river sections, Longmatan recorded the highest density at 0.43 kg/(h point operator times), while Jiujucun had the lowest CPUE at 0.011 kg/(h·times), and the <italic>A. dabryanus</italic> juvenile resource density in the Longmatan section was significantly higher than that of the other sites (<italic>P</italic>&lt;0.05), with no differences among the other seven sites (<italic>P</italic>&gt;0.05). Flow velocity, benthic fauna density, and water temperature emerged as primary drivers, with flow velocity bias explaining the highest rate of 69.1%. Juvenile density declined sharply as flow velocity increased from 0.15 to 0.86 m/s before stabilizing; benthic fauna density correlated positively with juvenile density, meaning higher benthic biomass was associated with greater juvenile abundance. Within the 18.9 to 20.7℃ temperature range, juvenile density decreased with the increase of water temperature. This study reveals the habitat distribution characteristics of <italic>A. dabryanus</italic> juvenile in the Luzhou section and the effects of flow velocity, benthic animal density, and water temperature, providing a scientific basis for the habitat protection and population recovery initiatives.