Spatiotemporal Distribution of Euphausia superba in CCAMLR Area 48 During 2012/2013 Fishing Season

Abstract:

Based on the trawl survey data of krill (Euphausia superba) fishery from the vessel “FURONGHAI” in 2012/2013 fishing season, the temporal and spatial distribution of krill resources were analyzed with the index of CPUE which was standardized as the yield of 3 n mile drag distance in one hour. The results showed that the monthly average of CPUE was relatively stable from January to June, but declined after July. The mean CPUE on sub-area 48.1 was the highest with (25.12 ± 31.04) t/h, and the lowest mean CPUE was on sub-area 48.3 with (11.49 ± 12.06) t/h. The change of net CPUE was greater in sub-area 48.1 than those in sub-area 48.2 and 48.3. Antarctic krill aggregated mainly in the depth of 0-100 m in sub-area 48.1 with the highest CPUE in 25-50 m layer, but they gathered in sub-area 48.2 mainly in 50-150 m layer with the highest CPUE in 100-150 m layer and in sub-area 48.3 mainly in 100-250 m layer with the highest CPUE in 200-250 m layer. Antarctic krill aggregations were mainly found in the coastal areas less than 500 m in depth which were formed as commercial fishing grounds, and the highest population density was in shallow water of 250 m with the CPUE of (17.54 ± 35.26) t/h. The average CPUE was lightly changed between 12–14 t/h in the grounds of 250–1500 m in depth, and the average CPUE was decreased to (9.62±9.54) t/h while the grounds was more than 1500 m in depth. The ground SST was mainly between –1–2℃, and the average CPUE was higher when the SST was in the range of –1–0℃. There were 5 major aggregations found in this survey, which could last more than 2 months with various densities over time. These results provide the basic data for searching Antarctic krill fishing ground and fisheries management, and provide some reference for commercial fishing as well.