Hydroacoustic observations of the vertical distribution of icefish Champsocephalus gunnari in the western part of the slope of the South Georgia Island in December 1999–January 2000

The dynamics of daily vertical migrations of icefish Champsocephalus gunnari was studied and some quantitative estimates were obtained by results of analysis of more than 150 fragments of echograms obtained with the use of an echograph of the "Priboi-101" echo sounder during the directed fishery for icefish in the subarea 48.3 in December 1999 – January 2000. The commercial concentrations of icefish can be considered by the type of the vertical distribution as bottom/pelagic ones, and the pelagic component of their biomass is great either during the night or day time. Of this, it can be concluded that assessments of Champsocephalus gunnari stock based on the results of bottom trawl surveys can be underestimated.