Abstract:Antarctic krill (Euphausia superba) is a vital part of the food web, supporting substantial fishery in the Southern Ocean. Krill represent the world´s largest animal protein pool, rich in lipids, nutritional long-chain polyunsaturated fatty acids, mineral elements, and carotene, with great potential for development. It is of great significance to understand the changes in fishing grounds, as they profoundly affect the krill population. The distribution characteristics of Antarctic krill fishing grounds in 48 areas were analyzed based on the production statistics of Antarctic krill fishing vessels in China from 2010 to 2019. The gravity center migration trajectory model and standard deviational ellipse (SDE) model were used to analyze the trends and characteristics of Antarctic krill fishing grounds. The results showed that the production of Antarctic krill was mainly concentrated in sub-region 48.1, accounting for 70.30% of total production. The yields of the 48.2 and 48.3 sub-regions showed little difference, accounting for 14.28% and 15.42%, respectively. The annual catch per unit effort (CPUE) curve increased over time, with a minimum value in 2012 and a maximum value in 2019. The monthly CPUE first increased and then decreased, with the minimum value in January and the maximum value in June. The annual and monthly gravity center of Antarctic krill in sub-region 48.1 moved southwest. The annual gravity center of Antarctic krill in sub-region 48.2 moved to the east, but the range of movement was small, and the monthly trends were weak. The annual gravity center of Antarctic krill in sub-region 48.3 moved to the south, and the monthly gravity center moved to the northwest. According to SDE analysis, krill fishing grounds in sub-region 48.1 had the widest distribution and the greatest dispersion, with the strongest directivity and the most obvious centripetal force in sub-region 48.3. The center of gravity of the fishing ground was distributed along the Bransfield Strait in sub-region 48.1, east of the South Orkney Islands in sub-region 48.2, and northeast of the South Georgia Islands in sub-region 48.3. Clustering results showed that the annual fishing ground gravity centers were concentrated in sub-region 48.1. The annual fishing ground gravity centers of sub-regions 48.2 and 48.3 were relatively concentrated in all years, except in 2017.
