Natural mortality rates for the Pacific blue marlin stock

This working paper updates sex- and age-specific natural mortality M for Pacific blue marlin. First, it develops an alternative estimator based on the Hamel & Cope (2022) maximum-age approach with Lorenzen rescaling. Both approaches are implemented using the new two-stanza growth model (TSGM) with age-determination uncertainty developed by Chang et al. (2025). Second, it revises the Brodziak (2021) meta-analysis framework, which combines multiple adult M estimators and rescales juvenile M using the Lorenzen allometric relationship.