ESC20_37_JP_CheckIndexByOM.pdf (134.69 kB)
A check of operating model predictions with discussion of aerial survey index issues related to continuing use of the Bali Management procedure.
reportposted on 2022-04-04, 07:49 authored by Norio Takahashi, Hiroyuki Kurota, Osamu Sakai, Tomoyuki Itoh, Doug ButterworthDoug Butterworth
Values of the longline CPUE index (one of the series required input to the Bali management procedure) are compared to projection results obtained from the operating model (OM). Recent observations for this index fall well within the 95% probability envelope predicted by base case OM in 2011. As regards the aerial survey (AS) index (the other required input to the procedure), the consequences of the non-availability of this index in 2015, and of a future reduction in the scale of the survey providing this index, are examined by conducting some projections. We find that non availability of the 2015 AS index and reduction of the scale of the associated survey have almost no impact on the performance of the procedure with respect to achievement of the management goal, stock conservation, and predicted TAC values. Accordingly we conclude that a declaration of the existence of Exceptional Circumstances is not essential at this time, and propose continuing the use of the Bali procedure to recommend the TAC for 2018-19 fishing seasons in 2016. Regarding the TAC to be recommended for the 2016 season, we conclude that no modification of the TAC value is required because no Exceptional Circumstances need to be declared and there seems to be no large sudden change observed in other recruitment indices for 2015.