Reports on abundance and biological information of toothfish in Division 58.4.4 a & b by Shinsei maru No. 3 in 2013/14 season

A survey was conducted to collect data of stock status and various biological information of toothfish in the research blocks 58.4.4b_1 (SSRU 58.4.4C) and 58.4.4b_2 (SSRU 58.4.4D) of Division 58.4.4b (Ob Lena Banks) from July 18 to September 20, 2014. A total of 88 hauls using normal trotline system were made in the blocks. Total catch of Dissostichus eleginoides (excluding those tagged and released) was 26.6 tonnes in the survey area. Mean CPUEs in terms of weight of D. eleginoides was 32.9 kg / km (CV = 11.3%) and 38.3 kg / km (CV = 13.6%) in the blocks 58.4.4b_1 and 58.4.4b_2, respectively. Fish in single-hooked and good physical condition constituted 72.6 and 74.1 % of the total catch in the block 58.4.4b_1 and 58.4.4b_2, respectively. Accordingly sufficient numbers of fish suitable for tagging was captured by using the normal trotline system as well as in the preceding season. A total of 159 fish of D. eleginoides in good physical condition and single-hooked were tagged and released during the survey, and total of 5 and 4 fish of D. eleginoides, which were tagged and released in the block 58.4.4b_1 and 58.4.4b_2 in the previous seasons, were recaptured in the same blocks, respectively. Nine sets in the block 58.4.4b_1 were affected by killer whales.