The scientific research fishing was conducted by the Greenstar (KOR) and Marigolds (UKR) in in Subarea 88.3 following the survey design (WG-FSA-2021/34). The total catch of D. mawsoni was 128909.3 kg comprising 4984 individuals. The CPUE for Dissostichus mawsoni varied among the research blocks; CPUE was higher in research blocks 883_3 and 883_4 with the mean range of 86.89 – 220 kg/1000 hooks, but lower in research blocks 883_6, 883_7 with the mean range of 28.3–120.64 kg/1000 hooks. The vessel calibration study in research block 88.3_4 has showed some differences in CPUE between the two vessels and this require future analysis. The tagging rate and tag overlap in Subarea 88.3 were 5.17 fish per ton and 92% overlap for Greenstar. And 5.02 fish and 73.5% for Marigolds.
The length frequency of D. mawsoni exhibited a bimodal distribution with mods near 70 cm and 150–160cm in block 88.3_4 and different with bigger fish predominance in block 88.3_3. In shallow water blocks 6 and 7 the high present of juvenile toothfish was observed. Regional and time differences in D. mawsoni female and male maturities were observed with stage 2 and 3. Otolith, stomach contents, gonad, fin and muscle samples were collected to obtain biological information of D. mawsoni. Also, hydrological information and plankton samples were collected through the fishing.
The main bycatch species and main prey of toothfish for the area of research were macrourids with CPUE up to 145 kg/1000 hooks. 95.5% of macrourids were identified on board as Macrourus caml. Whole specimens of bycatch species and otoliths of macrourids were collected for off water taxonomic identification and age determination.