Diel vertical migration of Antarctic krill aggregation in South Georgia Island in the austral winter season of 2013

The knowledge of diel vertical migration (DVM) of Antarctic krill aggregation (AKA) in the winter season will provide basic data to study the forming mechanism of fishing ground and provide the reference to study the overwintering strategy.Based on the data collected by the fishery survey on Antarctic krill population in the South Georgia Island during the austral winter 2013,the present study analyzes the DVM of AKA in the South Georgia Island.The results show average depth of AKA maintains 100 m to 300 m under sea surface,and the deepest and shallowest depths the of AKA occur at sunrise and night respectively.The average depth of AKA is deepening from July to September.The average depths of AKA show a significant monthly difference at night,in the day and at dusk.AKA often occurs in the deeper layer in the day and stays at surface at night.