Stock assessment of Patagonian toothfish (Dissostichus eleginoides) in Subarea 48.4 – addressing the convergence issues encountered in the 2021 assessment

Alternative models are presented for discussion to address a lack of convergence in the CASAL model fit to Patagonian toothfish (Dissostichus eleginoides) in Subarea 48.4 owing to the increasing quantity of data. Of the models that converged successfully the outcomes showed very similar diagnostic results, particularly the MPD fits. The main differences between the approaches taken, either fixing or estimating L_inf and k, was the impact on the reweighting of the effective sample size, tag dispersion parameter, YCS and the estimate of B₀.