Comparison of the catches and biological characteristics of Dissostichus mawsoni in Subarea 88.1 in seasons of 2002/03
and 2003/04

This report presents results of an exploratory fishery for Antarctic toothfish (D. mawsoni) conducted by the Russian vessels “Yantar” and “Volna” for two seasons of 2002/03 and 2003/04.
The analysis of data collected relates to catch composition, effort , CPUE, and biological characteristics in different SSRU, month and depth of sets longlines. The comparison of these resultants showed that in the general fishery effort (quantity of sets and hooks) in those two seasons were similar (233 sets and 1,55 mln. hooks in 2002/03, and 222 sets and 1,79 mln. hooks in 2003/04 ). But the total catch of D.mawsoni was very different:703 t in 2002/03, and 276 t in 2003/04. CPUE what were comparing in different SSRU has been also much smaller in 2003/04 season. The analysis of the length composition fish from the catches by longlines at different depth shows a tendency toward an increase in the modal length on the deeper ground .The modal length of toothfish caught in the different seasons and month did not change so strong. Meanwhile, the modal length of fish catches in the 2003/04 season was slightly lower than in the previous season. This trend is clearly seen when comparing the length frequencies of fish in different seasons among the largest individuals. It was very interesting that in the both seasons we had two modal classes: between 120-130sm, and second-near 145-150sm. The more detailed consideration of the length composition from the different SSRU catches showed that the individuals of the smaller size were caught closer to the shore while the larger ones of the second modal group were captured in the northern off-shore zone of the Ross Sea.