Incorporating spatial and temporal change in fishing and tagging effort into integrated stock assessments

Discussions at WG-FSA-2023 flagged the importance of distinguishing changes in outputs from integrated stock assessments from the characteristics of CCAMLR commercial fisheries’ datasets (WG-FSA-2023).  A focus on quantifying changes and correcting for potential biases in fishing and tagging effort was highlighted as one of a number of high priority tasks requiring attention. Examination of the mark-recapture model used in CCAMLR assessments, the Chapman estimator, was also noted as a related  component of this work.  Collaborative work between members responsible for assessments in Subarea 48.3, Division 58.5.1, Division 58.5.2, and Subareas 88.1 and 88.2A-B to test a number of statistical approaches has enabled strong progress on better understanding the nature of the problem as well as some of the key drivers at play.  This broader perspective is critical for being able to develop a clear plan for making concerted progress on these issues (Masere et al. 2024, WG-SAM-2024).