Abstract:

This study used transect survey data from the 36th Chinese National Antarctic Research Expedition in the Amundsen Sea to assess the spatial distribution of Antarctic krill (Euphausia superba) resource density and its relationship with environmental factors between 10th January and 5th February 2020. The key findings were: (1) the average density of Antarctic krill in the survey area was 6.36 g·m^–2, with an estimated total resource volume of 5.35×10⁶ t; (2) high-density areas of Antarctic krill in the Amundsen Sea were characterized by seabed depths of 500~1000 m and 3000~4000 m, proximity to the ice edge within 90 km, and offshore distances of 0~200 km and 350~540 km; (3) the environmental features of these high-density areas included sea surface temperature ranges of –1.1~–0.7 ℃, 0.1°~0.3 ℃, and 0.7~1.5 ℃; salinity levels between 33‰ and 34‰; and chlorophyll a concentrations of 1.8~2.2 μg·L^–1, 2.6~3.0 μg·L^–1, 3.0~3.4 μg·L^–1, 3.8~4.2 μg·L^–1, and 5.4~5.8 μg·L^–1; (4) Antarctic krill density was strongly negatively correlated with latitude, seabed depth, offshore distance, and distance from the ice edge (P<0.01), but was positively correlated with sea surface temperature (P<0.01); (5) the distribution of Antarctic krill in the Amundsen Sea showed weak correlations with salinity and chlorophyll a concentration.

Key words: Amundsen Sea, Antarctic krill, resource density, geographic factors, environmental factors