An example state-space age-structured stock assessment model for Pacific saury

An example age-structured model for Pacific saury stock assessment was proposed. Several treatments of the natural mortalities and age 0 spawning were tested. Based on the obtained results, we do not recommend free-estimation of the age-specific natural mortalities without validation of the biological plausibility of the obtained results. Introducing some assumptions on the natural mortalities would be a potential option. We also suggest to carefully consider the assumptions on the relative fecundity and times of spawning of age 0 fish.