Dye baits to reduce seabird bycatch
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Most seabirds are visual predators, and so are less likely to take bait if it is difficult to see. Dyeing bait blue so that it is hard to see against the water may therefore reduce bait loss and bycatch rates.
Supporting evidence from individual studies
A randomised, replicated and controlled experiment in February 1999, in the Northwestern Islands, Hawaii, USA (Boggs 2001), found that dyeing squid bait blue when setting hookless bait lines reduced attacks by black-footed Phoebastria nigripes and Laysan P. immutabilis albatrosses by 95% and 94% respectively, compared to lines set with un-dyed baits (measured as attacks/bird/100 branch lines). Twenty-four repeats of each treatment were used, set during the day to mimic longline setting for swordfish.Study and other actions tested