Preliminary assessment of the risk of albatrosses by longline fisheries

This document presents the preliminary results of applying the Spatially Explicit Fisheries Risk Assessment framework (SEFRA) developed by New Zealand to assessing the total mortality of great albatross caused by tuna longline operations in the southern hemisphere. The impacts of these mortalities on the sustainability of these albatross species are also considered. Seabird bycatch was modelled as a multiplier of a temporal and spatial overlap between fishing and seabird distributions. Seabird catchability, defined as a combination of seabird-specific vulnerability to fishing gears and gear-specific seabird catchability, was first estimated using the Japanese and New Zealand on-board observer data, and then applied to the total fishing efforts in the southern hemisphere for assessment of total annual bycatch mortality (ABM). High ABMs and high expected risks of longline bycatch to seabird population were identified in particular for wandering albatross, among seven species examined, even though the results were considered preliminary. The analysis demonstrated the capacity of SEFRA to deliver robust estimates of ABM and their impacts to seabird population from limited observer bycatch data, although some constraints and uncertainties, in particular for rarely caught species, remained. The authors intend to further develop the methodology and invite interested WCPFC members to join the collaboration.