Influence of sea ice and sea surface temperature on the abundance of Antarctic krill in Area 48.2

Abstract

In this paper we examine the relationship between Antarctic krill catch, sea ice concentration, and sea surface temperature (SST). Data on the Antarctic krill catch from 2003 to 2010 in CCAMLR Area 48.2 were combined with sea ice and SST data. Results showed that krill fishing in Area 48.2 took place from February to August each year but the catch was concentrated from March to July, with production during this period accounting for about 99.3% of the annual catch. Regression analysis showed that the catch per unit effort ( CPUE ) was clearly related to sea ice concentration and SST intervals. CPUE was negatively correlated with the area of sea ice among years ( R 2 =0.64), and the correlation was strongest ( R 2 =0.71) when sea ice concentration was greater than 90%. Over the months the CPUE initially increased, then decreased as the area of sea ice increased. The relationship was strongest ( R 2 =0.88) when the concentration of sea ice was 60%-70%. There was no negative correlation among years between CPUE and the ice-free area when SST was between -2℃and 3℃ ( R 2 =0.21), but there was a significant negative correlation when SST was between 1℃ and 2℃ ( R 2 =0.82). Over the months, CPUE initially increased then decreased with increasing sea ice-free area, and the relationship was strongest ( R 2 =0.94) when SST was between 0℃ and 1℃. This study shows that sea ice concentration and SST have significant effects on the abundance of krill in Area 48.2, and the findings have practical significance for the use and conservation of Antarctic krill resources.