A review of methodologies aimed at avoiding and/or mitigating incidental catch of protected seabirds.

Information on methods aimed at mitigating incidental mortality resulting from fisheries interactions have been released in a variety of local, national and international media. Recent published reviews in the field of bycatch mitigation have typically had a species or fishing method focus. This report presents the results of the seabird component of a global review of mitigation methods aimed at reducing mortalities of protected seabirds, marine mammals and reptiles and corals due to interactions with fishing gear in New Zealand fisheries and fisheries that operate using similar methodologies. The application of these mitigation methods to New Zealand fisheries were assessed, recommendations for the fisheries management made, and areas for further research in New Zealand identified. Factors influencing the appropriateness and effectiveness of a mitigation device include the fishery, vessel, location, seabird assemblage present and time of year (i.e. season). As such, there is no single magic solution to reduce or eliminate seabird bycatch across all fisheries. Realistically a combination of measures is required, and even within a fishery there is likely to be individual vessel refinement of mitigation techniques in order to maximise their effectiveness at reducing seabird bycatch. Retention or strategic management of offal and discards are recommended as the most effect measure to reducing seabird bycatch in longline and trawl fisheries. Other recommended methods for both demersal and pelagic longlining include paired bird-scaring lines, line-weighting and night-setting (in some fisheries). Along with offal and discard management, paired bird-scaring lines and reducing the time the net is on (or near) the surface are likely to be the most effective regime at this point to mitigate seabird interactions with the warp cables and net respectively. However urgent investigation is needed into more effective measures at reducing seabird interactions with the trawl nets.