Distribution of Soviet commercial fleet at krill fishery in the South Orkneys subarea (Subarea 48.2) during 1989/90

The results of analysis of haul by haul catch statistics of Soviet commercial fleet during 1989/90 season (totally 3614 hauls for the period from 1.11.1989 to 12.06.1990 are presented. Actually during the whole season fishing vessels worked in one fishing ground off the north-western edge of Coronation Island. Incidentally, CPUE shows regular intraseasonal variations from minimum (3.2 t/hour) in November to maximum (9.6 t/hour and 11.0 t/hour respectively) in February and March, and again decreases to 6.9-7.1 t/hour by May-June. Stability of the fishing ground is stipulated by peculiarities of the area hydrodynamics, such as availability of sustained doubling current around Islands and high water disturbance caused by topogenic effect. No temporally and spatially sustained krill aggregations (atractive to fishing vessels) are likely to form outside the main area (excluding November 1989). In November the commercial fleet fished oceanic krill aggregations formed in the major flow transporting krill northeastwards. The drift of fleet fishing the above aggregation was observed. Maximum CPUE (3.8 t/hour) was observed in the beginning of the period with gradual subsequent decrease to the level inacceptable to the fleet (2.5 t/hour) in the next to the last five days of November. After disintegration of that aggregation, existed for about 25 days, commercial vessels returned to Coronation Island. Krill drift velocity estimated on the basis of fishing ground shift velocity, amounted to 7.4 km/day or 8.7 cm/sec. The above value is compatible, however below to the drift velocity off Elephant Island (11-13 cm/sec), obtained earlier (Sushin, Myskov, 1992).