Progress report on the joint research for Dissostichus spp. in Subarea 88.3 by the Republic of Korea and New Zealand in 2018/19

The scientific survey was conducted by the Greenstar (KOR) in the research block 883_1–883_P9. Due to extreme ice conditions covering the southern part of 88.3, Janas (NZL) was not able to conduct its part of the survey. The total catch of D. mawsoni was 63,840 kg comprising 2,526 individuals. The CPUE for Dissostichus mawsoni indicated regional differences among the research blocks. CPUE was similar in research blocks 883_1, 883_3 and 883_4 with the range of 0.1110–0.1571, but much lower in research block 883_5, 883_P8, 883_P9 with the range of 0–0.0185. Tagging rate and tag overlap in Subarea 88.3 were 5.4 fish per tonne and 87%. The length frequency of D. mawsoni exhibited a bimodal distribution with modes near 70 cm and 150–160cm. Proportions for female maturity stages 1, 2, and 3 were similar, showing 33.3%, 37.1%, and 29.4%, respectively, whereas proportions for male maturity stages 1 and 2 accounted for 42.2% and 55.9%, respectively. Regional differences in female and male maturities were observed with stage 1 and 2. Otolith, stomach contents, gonad, fin and muscle samples were collected to obtain biological information of D. mawsoni.