Abstract: To elucidate the environmental drivers of energy accumulation in Antarctic krill (Euphausia superba), this study analyzed somatic energy density in both ovigerous and non-ovigerous adult krill collected from area 48 of the Southern Ocean between December 2023 and September 2024. Using Generalized Additive Mixed Models (GAMM), we investigated the relationship between somatic energy density and key marine environmental variables, and projected future changes in somatic energy accumulation under different climate scenarios. The results showed that the ovigerous krill exhibited significantly lower somatic energy density than non-ovigerous adults. Somatic energy density was positively correlated with sea surface temperature (SST) and chlorophyll a concentration (Chl.a), increasing with both variables. Model projections indicated that by 2050, somatic energy density will increase with rising sea surface temperature across all climate scenarios. By 2100, however, continued increase is only maintained under the SSP1-2.6 pathway, while a significant decline occurs under high-emission scenarios. Chlorophyll-a concentration exhibits a saturation effect in promoting energy accumulation, and long-term intensive climate change is projected to suppress krill energy storage capacity. These findings provide a scientific basis for assessing the environmental adaptability of Antarctic krill and formulating dynamic conservation strategies under climate change.