WCPFC Shark Post-Release Mortality Tagging Studies

Clarke S, Smith N, Lyon W, Francis M (2017) WCPFC Shark Post-Release Mortality Tagging Studies. In: IOTC - 13th Working Party on Ecosystems and Bycatch. IOTC-2017-WPEB13-INF17, San Sebastián, Spain

The Common Oceans (ABNJ) Tuna Project, initiated in October 2014 and running through December 2018, has provided $250,000 to the Western and Central Pacific Fisheries Commission (WCPFC) for shark post-release mortality (PRM) tagging studies. All of this funding is designed to support the cost of tagging equipment with no separate allocation for vessels, fuel or tagging personnel’s expenses. Fortunately, other Common Oceans (ABNJ) Tuna Project “shark data improvement” funds can support some of the other costs associated with running a large-scale tagging project including consultant time inputs for coordination and reporting of results. There is also funding within the Common Oceans (ABNJ) Tuna Project to support two workshops on bycatch mitigation and the first of these was held in Wellington, New Zealand from 24-27 January 20174. The second workshop will convene a panel again in 2018 to review, synthesize and interpret the shark tagging results in conjunction with similar studies in different fisheries. In addition to the Common Oceans (ABNJ) Tuna Project funding, the WCPFC received a €400,000 grant from the European Union for shark PRM studies in December 2016. Although the requirements of the two funding sources are slightly different, the intention is to use them in a synergistic manner to understand shark PRM and its implications for mitigation measures, e.g. no- retention measures, and population status assessments. The major difference in the two funding sources is that the EU funding is prioritized for tagging silky and oceanic whitetip sharks, with a secondary priority on thresher and porbeagle sharks, whereas the Common Oceans (ABNJ) Tuna Project funding can be used to fund PRM tagging of any WCPFC key shark species. The EU grant also provides funds for both tagging equipment and tagging personnel, but relies on the Common Oceans (ABNJ) Tuna Project for survey design inputs and reporting of results. The first of two workshops related to this study convened an expert panel of academic, government, and non-government scientists from around the world representing over 100 years of shark tagging expertise. The primary objective of the expert panel was to prepare and agree a survey design which would have optimal scientific rigor, cost-effectiveness and consistency with past and ongoing work. The report of the expert panel is appended to this covering note and describes how and why the panel decided to focus the tagging work on silky and shortfin mako sharks in longline fisheries. Oceanic whitetip shark was identified as being a species of interest but it was agreed that low catch rates make it unlikely that this study could obtain enough samples and that different tag types and tagging procedures would be preferred for this species. ...