First attempt of a sex-specific stock assessment model for Dissostichus eleginoides in Division 58.5.1

Following SC-CAMLR recommendations, we present the first attempt to implement a sex-based stock assessment model for D. eleginoides in Division 58.5.1. We estimated updated sex-specific biological parameters, including growth, maturity, and length–weight relationships, through Bayesian and generalized linear modelling frameworks. These parameters were then integrated into a Casal2 stock assessment model and compared with outputs from a single-sex model. Results revealed substantial differences between males and females, with males maturing earlier and attaining smaller maximum sizes, while females reached larger asymptotic lengths and matured later. Incorporating sex-specific parameters led to noticeable changes in estimates of spawning stock biomass and stock status relative to the single sex baseline.
Further work is required to refine the sex-based framework and ensure it is robust and reliable enough to support scientific advice for management.