Reducing seabird bycatch in the Hawaii longline tuna fishery

Mortality in longline fisheries represents a global threat to some species of pelagicseabirds. Regulations were adopted in 2001 to reduce seabird bycatch in the Hawaii longline tunafishery. We used a Poisson generalized additive regression modeling approach to evaluate thechange in seabird bycatch rates from the pre- to post-regulation period, and to evaluate the efficacyof alternative combinations of seabird bycatch reduction methods employed during the post-regulationperiod. Informative covariates of temporal and geo-referenced spatial effects of fishing effort andsampling variation commonly found with count data were included in the model to provide a betterinference of the effect of employing required changes in fishing gear and methods. We found a significant67% (95% CI: 62 to 72) reduction in the seabird bycatch rate following…