Comparison of outputs from integrated stock assessments using CASAL and Casal2 for the 2021 Patagonian toothfish (Dissostichus eleginoides) fishery at Heard Island and McDonald Islands (HIMI)

This paper compares key parameters and outputs for the 2021 Patagonian toothfish (Dissostichus eleginoides) fishery at Heard Island and McDonald Islands (HIMI) in CCAMLR Division 58.5.2 using both CASAL and Casal2.  Parameterisation, weightings and settings used in the Casal2 assessment were extracted from CASAL output files produced by the 2021 CASAL stock assessment for Patagonian toothfish at HIMI. The comparison between the CASAL and Casal2 implementation of this stock assessment model showed strong consistency. We note that the additional flexibility possible with Casal2 may allow us to explore improved parameterisations in future deliveries of the stock assessment for Patagonian toothfish at HIMI.