Krill distribution related to water structure and dynamics on the South Georgia shelf in January 2000 (AtlantNIRO-BAS Core Programme 1999/2000)

Research on water structure and dynamics, krill biomass assessment, biology and distribution were carried out in two standard boxes on the shelf and slope northwest and northeast of South Georgia. Eight hydroacoustic transects with hydrographic stations and RMT8+1 trawls were carried out in each box. Krill were distributed rather evenly throughout both boxes, but no dense concentrations were apparent. In the western box krill density was nearly 0.2 glm3 and in the eastern box was 1.8 - 4.7 glm3 • Juvenile krill of 30-36 mm length were observed in the shelf zone and larger specimens, including spawning and posts pawning females of 50 mm and larger, were distributed in slope zone and deep oceanic waters. According to these preliminary results, krill abundance on the South Georgia shelf in January 2000 was lower then usual and no concentrations suitable for commercial fishing were observed. Temperature and salinity measurements carried out on the standard hydrographic stations revealed oceanographic conditions were similar to the long term mean values. However on this survey we did not observe any of the usual gyres or eddies which lead to the formation and maintenance of krill concentrations.