Further Remarks on Gulf of Maine-Georges Bank Witch Flounder Assessment Results

Abstract

An SCAA assessment variant is argued to be preferable to the ASAP final model advocated by the SAW WG as the basis for witch flounder status assessment and management advice. The key differences introduced in this assessment variant are the possibility of domed selectivity, the inclusion of the LPUE times series, and an objectively-based down-weighting of the contribution to the likelihood of the CAA data. The main reasons that this variant is preferred (with comparisons to an SCAA assessment specified to mimic the ASAP final model) are a much reduced retrospective pattern (virtually eliminated for spawning biomass), notably better (though certainly still not complete) agreement with the results from the Sweep study in regard to estimates of abundance in absolute terms, and appreciably improved fits to the NEFSC survey indices of abundance.