Assessment of krill flux factors in waters of South Orkney Islands during summer 1996
This paper describes the results of an experiment conducted from 19 February to 7 March 1996 to assess krill flux factors in Subarea 48.2. The study area (80 x 240 n miles) was located in the zone of interaction between waters of the Antarctic Circumpolar Current (ACC) and the Weddell Sea. The study area covered sites where high krill concentrations had often been observed in the past. The geostrophic transport of krill across boundaries of the study area was calculated as a product of two variables integrated over the depth range 0 to 200 m: krill density (g/m3) and water mass transport (m3/sec) per nautical mile of the study area boundary. Also given are the results of krill density assessment, evaluations of geostrophic and wind-induced water transport along the study area perimeter. Mean krill transport rate was 7.2 tonnes/hour/n mile with a standard deviation of 15.5 tonnes/hour/n mile. Significant variability of krill transport across the study area boundary was observed, both in terms of the amount of biomass transported and the direction of flux. Due to the location of the study area, it was only possible to assess krill flux caused by waters of the southern periphery of ACC. Based on estimations of krill density and geostrophic
velocities obtained during the experiment, a preliminary estimate of krill outflow from the study area into adjacent areas would be approximately 9.2 million tonnes.