JABBA runs for the North Atlantic blue shark

This document presents a set of JABBA runs for Blue Shark in the North Atlantic for the period 1971-2021, intended to serve as a preliminary study contributing to the ICCAT 2023 stock assessment. Five different configurations of a Pella-Tomlinson biomass dynamic model were implemented, corresponding to different assumptions on the parameters r and m. Two dataweighting procedures were applied to the abundance indices (standardized CPUE series) used to fit the model, one with weights fixed in advance and another one with some components of the weights estimated within JABBA. Runs were conducted including all CPUE series accepted by the ICCAT Blue Shark Data Preparatory Meeting (scenario “All”). Four other scenarios corresponding to the different clusters of CPUEs indicated by the same Data Preparatory Meeting were also evaluated. In all, this resulted in 50 JABBA runs. This document presents detailed results for the scenario “All” and provides a comparison of results among all 50 runs. Most of the runs estimate that the harvest rate is currently below HMSY and the stock biomass around or above BMSY.