Direct comparison of seabird avoidance effect between two types of tori lines in longline fishing experiments
Seabird avoidance performance of two types of tori-lines specified in the WCPFC seabirds conservation and management measure, i.e., "1a) Tori line" and "1b) Tori line (light streamer)" was compared in designed experiments of longline fishing using commercial and research vessels in the western North Pacific. The frequency of bait-taking behavior and bycatch rates of seabirds were examined using generalized liner mixed models (GLMM). Results of the analysis indicated that "1b) Tori line (light streamer)" further reduce both bait-taking behavior and bycatch of seabird compared to "1a) Tori line". Considering its better performance in seabird avoidance as well as its practical utility due to numerous tangle-free streamers and light-weight structure, "1b) Tori line (light streamer)" stands as a good option for avoiding seabird bycatch in longline fishery.