Incorporating tagging data within the Casal2 integrated stock assessment of Patagonian toothfish (Dissostichus eleginoides) for the Heard Island and McDonald Islands (HIMI) longline fishery in Division 58.5.2

Within CCAMLR, the agreed mark-recapture model in integrated assessment models used to estimate biomass from toothfish tagging studies is the Chapman estimator.  Ongoing work has explored approaches to improve the reliability and robustness of the mark-recapture estimates that are derived from this method. An interim step has been to provide a degree of separation from the integrated assessment by estimating a biomass time series externally; yet still utilizing a Chapman estimation formulation. This paper extends previous work that estimated biomass in this manner for core areas and subareas within the Heard Island and McDonald Islands (HIMI) fishery in Division 58.5.2.  Specific additions to this previous work are the provision of results from MPD assessment runs of the 2024 HIMI Patagonian toothfish assessment for two designated core areas along with three subareas.  Some discussion on future direction with the assessment model, including tagging data, is also provided.