Potentially significant variables explaining bycatch and survival rates and alternative data collection protocols to harmonize tuna RFMOs’ pelagic longline observer programmes

Also published as Appendix 1 to WCPFC-SC11–2015/EB-IP-05.

Scientific observer data are key to conduct robust stock assessments, identify and understand trends and patterns in nominal and standardized catch and survival rates and catch levels, and assess the performance of conservation and management measures. Across disciplines, including fisheries, there has been increasing awareness of the benefits of providing for the interoperability of datasets, metadata catalogues and dataset formats.
The Joint Tuna Regional Fisheries Management Organizations’ (RFMO’s) Technical Working Group-Bycatch prioritized adopting minimum data fields and standardized collection protocols by pelagic longline observer programmes to enable the interoperability of the RFMOs’ observer programme datasets. Standardizing observer programme data fields, data collection protocols and observer database formats facilitates comparisons between RFMOs, enables pooling data necessary to support large spatial scale analyses within and across RFMO convention areas, and enables standardization of training materials and courses within and across regions. Harmonizing the tuna RFMOs’ observer data and improving the quality of data collection protocols further promise to improve assessments of fishery effects on bycatch species, identify factors that significantly explain catch and survival rates, evaluate the performance of bycatch mitigation methods, and support other functions of the tuna RFMOs.
A January 2015 meeting of experts on tuna longline fisheries identified a need for a systematic review of existing information collected by the tuna RFMO longline observer programmes in order to identify priority gaps in data that hamper our understanding of longline bycatch. As a starting point, the group recommended developing a comprehensive list of variables that could be collected through tuna RFMO human and electronic monitoring onboard observer programmes that have been documented to have significant effects on catch and mortality rates of taxa susceptible to capture in pelagic longline fisheries, and alternative data collection protocols for each prioritized variable. This report was commissioned by the Western and Central Pacific Fisheries Commission under the ABNJ (Common Oceans) Tuna Project to implement this recommendation.