Study

Reducing seabird bycatch in longline fisheries by means of bird-scaring lines and underwater setting

  • Published source details Løkkeborg S. (2001) Reducing seabird bycatch in longline fisheries by means of bird-scaring lines and underwater setting. Pages 33-41 in: E. Melvin & J. Parrish (eds.) Seabird Bycatch: trends, roadblocks and solutions. Alaska Sea Grant, Fairbanks.

Actions

This study is summarised as evidence for the following.

Action Category

Weight baits or lines to reduce longline bycatch of seabirds

Action Link
Bird Conservation

Set lines underwater to reduce seabird bycatch

Action Link
Bird Conservation

Use streamer lines to reduce seabird bycatch on longlines

Action Link
Bird Conservation
  1. Weight baits or lines to reduce longline bycatch of seabirds

    A randomised, replicated and controlled experiment in February 1999, in the Northwestern Islands, Hawaii, USA (Løkkeborg 2001), found that weighing bait when setting hook-less bait lines, reduced attacks by black-footed Phoebastria nigripes and Laysan P..immutabilis albatrosses by 93% and 91% respectively, compared to lines set with un-dyed baits (measured as attacks/bird/100 branch lines). There were 24 replicates of each treatment, with squid bait weighed down with a 60 g swivel weight. Lines were set during the day and mimicked swordfish longline setting.

     

  2. Set lines underwater to reduce seabird bycatch

    A randomised, replicated and controlled experiment, with 11 repeats of each treatment (each approximately 6,500 hooks), off the coast of mid-Norway during daylight in August 1998 (Løkkeborg 2001), found that longlines set using an underwater setting funnel significantly reduced the number of seabirds caught compared with control lines, set without a funnel (six birds and 0.08/1,000 hooks vs. 74 birds and 1.75/1,000 hooks). The majority of hooked birds were northern fulmars Fulmarus glacialis.

     

  3. Use streamer lines to reduce seabird bycatch on longlines

    A randomised, replicated and controlled experiment off the coast of mid-Norway in August 1998 (Løkkeborg 2001), found that two streamer lines both significantly reduced the seabird bycatch on longlines compared with lines set with no streamer (no birds caught with the 11 repeats using the advanced streamer, two birds and 0.03 birds/1,000 hooks with the 11 repeats of the simple streamer vs. 74 birds and 1.06 birds/1,000 hooks for 11 sets with no streamer line). The majority of hooked birds were northern fulmars Fulmarus glacialis. Each set contained approximately 6,500 hooks and was set during daylight. Both streamers were 80 m long and hung 7-8 m above sea level; the advanced line had four gillnet float rings at the trailing end and twelve 8 cm wide yellow tarpaulin streamers, 5 m apart, 0.5-3 m long; the simple line had a punctured buoy at the trailing end and six, equally placed, 30 cm, red plastic streamers.

     

Output references
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