Radii of annual elements of otoliths of mackerel icefish (Champsocephalus gunnari) from the South Georgia shelf were determined by analyzing data on length frequency distribution of fish in catches simultaneously with otolith radii of fish taken in the period July to September. The latter was done using specimens from strictly defined age groups. It is suggested that the determined radii of annual elements of otolith could be used to adjust age assessments of fish longer than 30 cm having an enlarged otolith centre. An age/length key for the third quarter of the year was also calculated.