2020 sole dynamic Schaefer production model results

Abstract

The sole resource is modelled by a dynamic Schaefer production model which allows for a drop in the value of the intrinsic growth rate parameter from 2000 onwards. The model is fit to the available CPUE and survey abundance indices. These data are not sufficiently informative to be able to distinguish amongst fairly wide ranges of pre- and post-2000 intrinsic growth rate parameters. Nevertheless, all suggest that the sole resource has never been substantially depleted (being well above its MSY level), and furthermore that the current replacement yield and MSY are reasonably robustly estimated in the ranges of 275-350 and 490-720 mt respectively. Given that this update 2020 assessment indicates slightly lower values for resource productivity than in 2019, consideration should be given to some reduction in the current TAC of 502 mt.