Stochastic projections for the 2019 assessment of the toothfish (Dissostichus eleginoides) resource in the Prince Edward Islands vicinity

• Main Authors: Brandão, Anabela, Butterworth, Doug S
• Format: Report
• Language: English
• Published: Faculty of Science 2019
• Subjects: Tac; Prince Edward Islands
• Online Access: http://hdl.handle.net/11427/30762; https://open.uct.ac.za/bitstream/11427/30762/1/FISHERIES_2019_OCT_SWG-DEM_33%20Toothfish%20stochastic%20projections.pdf

For stochastic future recruitment and for annual catch levels of 0, 200 and 400 tonnes, the median of the spawning biomass estimates for the New Base case model drops initially, but returns to its current level within a decade. For higher catch levels of 543 and 643 tonnes, the median of the spawning biomass estimates return to current levels within only 15 and 20 years respectively. However, for variants of this model that attempt to improve the fit to the trotline CPUE or which adjust the projected recruitments to reflect a possible regime shift, it is only annual catches of 200 tonnes that maintain the spawning biomass above its current level at the end of a 20 year period. This suggests that consideration should perhaps be given to recommending some decrease in the present annual TAC of 543 tonnes.