figshare
Browse
CSAM Working Paper 2015_13.pdf (4.01 MB)

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

Download (4.01 MB)
report
posted on 2022-02-28, 04:36 authored by Rebecca A Rademeyer, Doug ButterworthDoug Butterworth
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.

History

Department/Unit

Department of Mathematics and Applied Mathematics, University of Cape Town