The experimental trials of line weighting options for reduction of incidental mortality of seabirds in Korean tuna longline vessels

The study tested the effect of Lumo Leads on seabird bycatch and catch rates in the Korean tuna longline fleet. Lumo Leads (previously called "safe leads") add weight to longlines by threading the line through a channel, rather than crimping to the line. This can reduce flyback speed and improve crew safety. Lumo Leads also provide protection from exposure to lead weights, and contain optional fluorescent dye to provide an alternative to single-use glow sticks or electric lights.  Unweighted branch lines caught more than twice the number of seabirds compared to weighted branch lines, although branch weighting alone was not able to completely reduce bycatch. Adding more weight and placing weights closer to the hook increased branch weighting effectiveness as a bycatch mitigation technique. However, catch rate for albacore tuna on weighted lines was significantly lower than on unweighted lines. Catch rate also decreased as weight of the leads increased. There was no effect of branch weighting on catch rates for southern bluefin tuna or yellowfin tuna.