Seabird by-catch and bait loss in longlining using different setting methods

Sea-birds taking baits during longline setting occationally become caught and are killed, while the associated bait loss may have serious impact on longlining efficiency and profitability. Two different setting methods were tested as a solution to this problem; lines were set either through a setting funnel that guided the baited line beneath the sea surface or when using a sea-bird scaring device. Bait loss and the catches of target species and sea birds were compared with those of lines set without using such devices. Accidental catches of birds were reduced by both methods, most effectively by the sea-bird scarer. Losses of mackerel bait were also significantly reduced by using the scarer, but not by using the setting funnel. No increase in the catches of target species was demonstrated by using either of the setting methods. However, bait loss caused by sea birds was regarded as a minor problem in this fishing experiment. Suggestions on how to improve the efficiency of the two methods tested were discussed.