Report of the Expert Workshop on Shark Post-Release Mortality Tagging Studies: Review of Best Practice and Survey Design

The Areas Beyond National Jurisdiction (ABNJ, or Common Oceans) Tuna Project is a Global Environment Facility (GEF)-funded, FAO-implemented programme of work designed to encourage and reinforce sustainable tuna fisheries. The ABNJ Tuna Project addresses a number of aspects of global tuna fisheries including supporting a systematic application of a precautionary and ecosystem-based approach to management, reducing illegal fishing and improving compliance, and mitigating adverse impacts of bycatch on biodiversity. Under the third component, the Western and Central Pacific Fisheries Commission (WCPFC) is leading work on shark data improvement, shark assessment and management, and bycatch mitigation. The need for better estimates of mortality for sharks in tuna fisheries cuts across each of these themes. Therefore, in addition to working toward improving the data collected by fishers and observers, the ABNJ Tuna Project has identified that tagging studies designed to quantify the survival of discarded/released sharks are required to provide critical new inputs for assessment and mitigation studies. In particular, such studies will assist in evaluating whether existing WCPFC conservation and management measures (CMMs) prohibiting retention of all oceanic whitetip (Carcharhinus longimanus, OCS), silky (C. falciformis, FAL) and whale (Rhincodon typus, RHN) sharks are effective in reducing mortality and conserving these shark stocks. In support of such work, the European Union (EU) recently granted WCPFC additional funding for shark post-release mortality (PRM) tagging studies.

In order to design a shark PRM tagging study having optimal scientific rigor, cost-effectiveness and consistency with past and ongoing studies, the WCPFC, in partnership with the Pacific Community (SPC) decided to convene an expert workshop to advise on these issues. The goal of the exercise was to provide a set of scientifically robust and practical protocols for shark PRM studies in general, as well as a specific design for the ABNJ- and EU-funded work which addresses the technical objectives and can be achieved with the available budget and timeframe. A workshop format was proposed in order to take full advantage of existing experience with PRM studies across species and fisheries, thereby avoiding common mistakes and duplication and maximizing the value of available resources. The workshop was announced in September 2016 under WCPFC Circular 2016/51 which called for nominations of scientists with direct experience in the subject and/or an affiliation with WCPFC member countries.