Review and evaluation of three mitigation measures - bird-scaring line, underwater setting and line shooter - to reduce seabird bycatch in the Norwegian longline fishery

摘要

Seabirds scavenge baits from the hooks of commercial longlines, resulting in incidentalseabird mortality and bait loss. As interactions between seabirds and longline fishing maycause decline in seabird populations and reduced gear efficiency, the potential for solving thisproblem by means of various mitigation measures has been tested. Four fishing experimentswere conducted in commercial longlining in the north Atlantic to investigate the effectivenessof a bird-scaring line, underwater setting and a line shooter in reducing seabird bycatch duringlongline setting. These results are reviewed and the performance of the mitigation measures isevaluated. Accidental catches of birds were reduced by all three methods, most clearly by thebird-scaring line that had an efficiency of 98-100%. The experiments also produced areduction in bait loss and raised the catch rates of target species, which are importantincentives for fishermen to employ mitigation measures.