An at-sea trial of seabird mitigation gears including three weighted branch line specifications for tuna longline fisheries

Citation
Ochi D, Katsumata N, Oshima K (2017) An at-sea trial of seabird mitigation gears including three weighted branch line specifications for tuna longline fisheries. In: WCPFC Scientific Committee 13th Regular Session. WCPFC-SC13-2017/EB-IP-17, Rarotonga, Cook Islands
Abstract

In this study, seabird attacking behavior toward branchline bait and bycatch under use of three weighted branchline designs (LUMO leads, and Blinking weights fixed at 30cm apart from hooks and Blinking weights fixed just upon hooks) were compared with that of a hybrid tori-line by the experimental longline operations to evaluate effectiveness of these gears as seabird bycatch mitigation gears. During research cruises in 2014 and 2015, longline operations had been set around the Northwest Pacific. All branchline designs had exhibited similar effect to torilines about reduction of attacking rate and bycatch rate but blinking weight tended to be less effective when it
placed apart from hook.