Statistical Catch-At-Length assessment results for Sebastes mentella and S. fasciatus in Units 1 and 2

• Main Authors: Rebecca A Rademeyer, Doug Butterworth
• Format: Report
• Language: unknown
• Published: 2022
• Subjects: Biological Mathematics; Applied Statistics; Biostatistics; Canadian redfish populations; statistical catch-at-length (SCAL) assessment; fisheries resource management; catch-at-length data; assessment models; stock assessment models; Sebastes mentella
• Online Access: https://doi.org/10.25375/uct.19114769.v1; https://figshare.com/articles/report/Statistical_Catch-At-Length_assessment_results_for_Sebastes_mentella_and_S_fasciatus_in_Units_1_and_2/19114769

Past attempts at Statistical-Catch-At-Length assessments for the redfish populations in Units 1+2 have struggled to reconcile survey biomass trends with survey catch-at-length data. Here it is shown that reconciliation is possible under the assumptions of natural mortality decreasing with age, and a situation where only occasionally extraordinarily strong year classes enter the populations. While the species-disaggregated assessments developed here could be refined (and species-aggregated), it is suggested that first discussions should be held to agree or otherwise on the reasonableness/plausibility of these core aspects of the dynamics of these species. The situation of occasional extraordinarily strong year classes has implications, which are discussed, for the basis under which reference points for these populations are best evaluated.