Characteristics of krill aggregations in 48.4 subdivision during January–February 2000

It has been showed that krill spatial distribution in 48.4 Subarea was characterized by presence of non-aggregated and scattered form, swarms, when surveying (January 17-February 1, 2001).. There have been revealed differences between spatial distribution patterns of krill aggregations of different type in relation to water mass structure and dynamics.
The distributional features and physical characteristics of some 2400 krill swarms detected and sized acoustically in the study area have been described. Comparative results have been given between swarm parameter means in different areas and seasons.
There has been made an analysis of krill biomass horizontal and vertical distributions in the study area in relation to characteristics of the aggregations recorded. The effect of spatial distribution of krill aggregations of different type had an on krill biomass horizontal and vertical distribution has been shown. Major krill biomass (of about 64%) was concentrated in krill swarms within the meander and eddies zones of the Weddell Sea (14% of study area), being observed in upper 80 m depth level.
There has been made an analysis spatial distributional patterns of krill aggregations of different type and vertical distribution of krill biomass density with a view to revealing potential fishing grounds to remove the recommended precautionary catch limit. There have been revealed that potential fishing grounds could be situated within the zones of swarms concentrations where biomass density was than 1.5g/m^3. Biomass in the potential fishing grounds amount about to 1,7 mln.t It has been manifested that biomass removal corresponding to recommended precautionary limit could be possible from such grounds , however, the predicted catch per trawling hour is low
Therefore, the investigations carries out demonstrated a practical interest in studying spatial distributional patterns of krill aggregations of different type to acquire knowledge in natural regularity of krill biomass horizontal and vertical distribution and to reveal potential fishing grounds to remove the recommended precautionary catch limit. The latter is an important link for regulating fishery according to the adopted ecosystem approach.