The stock sizes for five research blocks (486_1, 486_2, 486_3, 486_4 and 486_5) were estimated by the Petersen estimator and the CPUE x seabed analogy method using updated CCAMLR C2 data and reference area sizes. The stock size estimate using the Petersen estimator was similar to that using the CPUE method (using Division 88.2H as a reference area) for Dissostichus mawsoni in block 486_2. However, the estimates using the Petersen estimator were different from those using the CPUE method in other blocks where the Petersen estimator was applicable. Predicted numbers of tag recaptures from the estimated stock sizes using the both Petersen and CPUE methods (using Division 88.2H as a reference area) were relatively consistent with the observed numbers for D. mawsoni in the block 486_2 for 2012/13 and 2013/14 seasons. However the predicted and observed numbers using either method were inconsistent for Dissostichus spp. in other blocks.
As we proposed at the last WG-SAM meeting, since we have yet to obtain enough evidence to estimate plausible stock size, and accordingly have yet to estimate appropriate catch limit, we propose to continue the current research operation for at least 3 years with the same sample size as decided at the last CCAMLR meeting in the current research blocks except in block 486_3, in order to promote successful stock assessment. On the other hand, we preliminarily estimated sample sizes for 2014/15 using the CPUE analogy method for Dissostichus spp. in all blocks generally following the procedure recommended at the last WG-FSA meeting. The results of calculations were generally consistent with the current sample sizes, except for D. eleginoides in blocks 486_1&2.
In research block 486_3, the number of observed recaptures, which was significantly lower than those predicted, can be a result of limited number of hauls (only 13 and 14 hauls in 2013 and 2014, respectively) associated with the small catch limit. Regarding relatively high CPUE in the area, we propose to increase the catch limit from current 50 tonnes to 100 tonnes under the exploitation rate of 3 % in order for succeeding in the tagging experiment.
In addition, we propose to allow flexibility (i.e. carried-over and buffer zone) in cases of research operations under extraordinary adverse ice-conditions, as detailed in WG-SAM-14/01 (2014).