Preliminary results of the experiments on the krill transport study in the South Orkney area (April 1992)

From 18 to 23 April hydroacoustic, oceanological and trawling surveys were carried out within the square of 30 x 30 miles northwestwards of Coronation Island in the fishing fleet operation area. The krill biomass was estimated within the square at the start and the end of works. It amounted to 56.1 thous. t and 61.2 thous. t respectively. During the period remained the hydroacoustic assessment of krill density and oceanological stations were carried out along the square perimeter. Four dublicates of perimeter were made. Control hauls with midwater trawl were made on the regular basis. The average estimates of krill density were obtained by 15-miles intercepts of the perimeter, along with mean water flow and geostrophic currents. The balance of krill input and output for the square was calculated based on these values. In the .first two dublicates the aggregation of krill was observed within the contour and in the second two - loss of krill. The aggregation was 52 thous. t greater than the loss. The researches show that the fishing aggregation stability depends essentially on the heterogeneity of the current's field. The researches were carried out by R/V "Dmitriy Stefanov" owned by PPO "Yugrybpoisk" (Ukraine).