Abstract: Antarctic krill (Euphausia superba) are widely distributed in the Southern Ocean. It is a key species in the Southern Ocean ecosystem and an important food source for whales, fish, penguins and birds, and their density and distribution are strongly affected by environmental factors. Based on acoustic evaluation and survey data from the 36th Chinese Antarctic Research Expedition, One-way ANOVA and bivariate correlation analysis were used to study the spatial distribution characteristics and the relationship with chlorophyll concentration of Antarctic krill in the Amundsen Sea from January 9, 2020 to February 5, 2020. The results showed that the average resource density of Antarctic krill in the Amundsen Sea was 6.36 g·m^–2, with the highest proportion (68.18%) falling in the density range of 0~5 g·m^–2. Spatial variability in Antarctic krill density was statistically significant (P<0.05). Antarctic krill resources were concentrated in the inshore (72.75°S—76.25°S) and western regions (150°W—158°W) of the Amundsen Sea. The average chlorophyll concentration in the study area was 3.54 mg·m^–3, with the highest proportion (38.31%) falling in the 2~3 mg·m^–3 concentration range. There was also significant spatial variability in chlorophyll concentrations (P<0.05), which were higher in the coastal waters (72.75°S—76.25°S) and on the eastern and western sides (114°W—119°W and 140°W—158°W) of the Amundsen Sea. A significant positive correlation between chlorophyll concentration and the resource density distribution of Antarctic krill was detected (P<0.05).

Key words: Euphausia superba, acoustic evaluation, resource density, chlorophyll concentration, spatial distribution, Amundsen Sea