Actively deterring birds from baited hooks. Single bird scaring line The use of a single bird scaring line has been shown to be an effective mitigation measure in a range of demersal longline fisheries, especially when used properly (Xxxxxx et al. 1996; Xxxxxxxxx 1998, 2001; Xxxxxx et al. 2001; Xxxxx 2001; Xxxxxxxxx & Xxxxxxxxx 2002; Effective only when streamers are positioned over sinking hooks. Single bird scaring lines can be less effective in strong crosswinds (Xxxxxxxxx 1998; Brothers et al. 1999; Xxxxx et al. 2000; Xxxxxx et al. 2001; Xxxxxx et al. 2004). In the event of strong crosswinds, bird scaring lines should be deployed from the windward side. This problem can also be overcome by using paired bird scaring lines (see below).The Effectiveness is increased when used in combination with other measures – e.g. night setting, appropriate weighting of line and judicious offal management. The use and specifications/performance standards are fairly well established in demersal longline fisheries. However, there is scope to improve further the effectiveness and practical use of bird scaring lines on individual vessels or vessel type. Current minimum standards vary. CCAMLR was the first conservation body that required all longline vessels in its area of application to use bird scaring lines (Conservation Measure 29/X adopted in 1991). The bird scaring line has gone on to become the most commonly applied mitigation measure in longline fisheries Xxxxxxxxx 2003) effectiveness of the bird scaring lines is also dependent on the design, the aerial coverage of the bird scaring line , seabird species present during line setting (proficient divers being more difficult to deter from baits than surface feeding birds) and the proper use of the bird scaring line. The aerial coverage and the position of the bird scaring line relative to the sinking hooks are the most important factors influencing their performance. There have been a few incidents of birds becoming entangled in bird scaring lines (Xxxxx et al. 2007). However it must be stressed that the numbers are minuscule, especially when compared with the number of mortalities recorded in the absence of bird scaring lines. Bird scaring lines remain a highly effective mitigation measure, and efforts should be directed to improving further their design and use so that their effectiveness can be improved further. worldwide (Xxxxxx et al. 2004). CCAMLR currently prescribes a range of specifications relating to the design and use of bird scaring lines. These incl...
