A potential indicator for non-retained sharks in support of an ICCAT ecosystem report card

Citation
Coelho R, Santos C, Rosa D, Lino PG (2020) A potential indicator for non-retained sharks in support of an ICCAT ecosystem report card. ICCAT Collect Vol Sci Papers 76:73–83
Abstract

Also published as IOTC-2019-WPEB15-INF06.

This work follows the requests and ongoing work from the ICCAT Sub-Committee on Ecosystems to develop an Ecosystem report card, in this case related with non-retained sharks. As a starting point, the bigeye thresher shark was used given its low productivity and susceptibility to longline fisheries, determined in the latest sharks ERA. The preliminary indicator developed now is based on a standardized CPUE from operational level fishery observer data, from the Portuguese pelagic longline fleet (2008-2016). This indicator should be considered preliminary, at this stage provided mostly as a starting point for discussion at the SC-ECO, since it only has data from one fleet. If there is an interest to progress the development of these types of indicator, then it is recommended that detailed observer data from other fleets should be incorporated, especially fleets from CPCs that interact more with those pelagic shark species.