A review of methodologies aimed at avoiding and/or mitigating incidental catch of seabirds in longline fisheries

Information on methods aimed at mitigating incidental mortality resulting from fisheries interactions have been released in a variety of local, national and international media. This report presents the results of a review to reduce contacts and mortalities of seabirds due to interactions with longline fishing gear. 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. While having a New Zealand fisheries focus, the results of this review are likely to be applicable to longline fisheries worldwide. 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 has the potential to avoid seabird bycatch. Other methods recommended to mitigate against seabird bycatch include paired bird-scaring lines, line weighting and night setting.