A check of operating model predictions from the viewpoint of the management procedure implementation in 2016

Takahashi, Norio; Kurota, Hiroyuki; Sakai, Osamu; Itoh, Tomoyuki; Butterworth, Doug S

A check of operating model predictions from the viewpoint of the management procedure implementation in 2016

Working Paper

2016

Publisher

University of Cape Town

Department

Marine Resource Assessment and Management Group

Faculty

Faculty of Science

Abstract

Values of the core vessels’ longline CPUE and aerial survey (AS) indices (two required inputs to the Bali management procedure) are compared to projection results obtained from the operating model (OM). Recent observations for the CPUE index fall within the 95% probability envelope predicted by the Base case OM in 2011. The AS index values for 2012, 2014 and 2016, however, are outside the range predicted by this Base case. The 2016 AS index value remains outside the 95% probability envelope predicted even for the Robustness Test which assumes higher variability for the projected AS index, though the index values for 2012 and 2014 fall within this envelope. This constitutes a possible indication of Exceptional Circumstances. Through discussion of the Exceptional Circumstances reflected by the 2016 AS index, together with the other elements contributing to Exceptional Circumstances and consideration of their severities, the ESC needs to formulate management advice for the action required to calculate TAC for 2018-2020 fishing seasons. Regarding the TAC to be recommended for the 2017 season, we consider that no modification of the TAC value is required given that there has been no unexpected change in the fisheries indicators examined and there are no indications of any decline in recruitment indices for 2016.

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