Project 68: Estimation of seabird mortality across the WCPFC Convention Area

Citation
Peatman T, Abraham E, Ochi D, et al (2019) Project 68: Estimation of seabird mortality across the WCPFC Convention Area. In: WCPFC Scientific Committee 15th Regular Session. WCPFC-SC15-2019/EB-WP-03, Pohnpei, Federated States of Micronesia, p 66
Abstract

Project 68 aims to: estimate total annual seabird mortalities in WCPFC fisheries; assess mortality per year since the first WCFPC seabird CMM and assess whether there is any detectable trend; describe the methods used, including treatment of data gaps; identify limitations in available data; and, given available data, generate advice on what further level of seabird assessment can be conducted.

Total longline seabird bycatch and mortalities were estimated using a Monte Carlo simulation modelling framework. Bycatch rate distributions for the simulation models were estimated using Generalised Additive Models of bycatch rate (individuals per ‘000 hooks). Seabird condition at-vessel models were used to estimate distributions of proportions of bycatch that were alive at-vessel. Purse seine bycatch and mortalities were estimated using a non-parametric bootstrapping procedure. Additionally, species-specific seabird bycatch for southern hemisphere longline fisheries was estimated based on the overlap between fishing effort and estimated seabird distributions...