International Fisheries Stock Assessment Review Workshop

2020 Workshop


Because of COVID restrictions and for reasons of time, the 2020 IWS differed from earlier events in this annual series. It had to be held as a virtual rather than a physical meeting, and the material considered had to be limited. The questions posed to the Panel were developed by the Acting Chief Director of DEFF Fisheries Branch, who negotiated the format of the event with the Panel members.



General 1: International review of some aspects of the Island Closure Experiment. FISHERIES/2020/DEC/SWG-PEL/REVIEW/01. 2pp.
General 2: Document list. FISHERIES/2020/DEC/SWG-PEL/REVIEW/02. 7pp
General 3: Presentation of the Panel Report. 10 slides.
General 4: Final Panel Report. FISHERIES/2020/DEC/SWG-PEL/REVIEW/07. 7pp.


Primary papers

P1: Question Q1 - Summary document. FISHERIES/2020/DEC/SWG-PEL/REVIEW/03. 36pp.
P2: Question Q2 - Summary document. FISHERIES/2020/DEC/SWG-PEL/REVIEW/04. 23pp.
P3: Question Q3 - Summary document. FISHERIES/2020/DEC/SWG-PEL/REVIEW/05. 5pp.


Potential primary paper

Note: For reasons of time the Panel did not address Question Q4

P4: Question Q4 - Summary document. FISHERIES/2020/DEC/SWG-PEL/REVIEW/06. 13pp.


Background documents


BG1: Penguin Island Closure Task Team. Specifications for operating models to evaluate bias in estimation methods in accordance with recommendation A1 of the 2014 International Review Panel. MARAM/IWS/DEC15/PengD/P1. 10pp.
BG2: Penguin Island Closure Task Team. Consolidated analyses produced in implementation of the approaches described in document MARAM/IWS/DEC15/PengD/P1. MARAM/IWS/DEC15/PengD/P2. 40pp.
BG3: Dunn, A., Haddon, M., Parma, AM. and Punt AE. International Review Panel report for the 2015 International Fisheries Stock Assessment workshop. MARAM/IWS/DEC15/General/8. 23pp.


BG1: Ross-Gillespie A. and Butterworth DS. Penguin power analyses using the approach recommended by the international panel: methods and results. FISHERIES/2016/NOV/SWG-PEL/Peng/01. Also referenced as MARAM/IWS/DEC16/Peng_Clos/P1. 31pp (incl. Addendum).
BG2: Butterworth DS. On the use of aggregated vs individual data in assessment models. MARAM/IWS/DEC16/Peng_Clos/P3. Also referenced as FISHERIES/2016/AUG/SWG-PEL/65. 6pp.
BG3: Sherley RB. Additional analysis suggested in response to differences in variance estimates between Sherley (2016) and Ross-Gillespie & Butterworth (2016). MARAM/IWS/DEC16/Peng_Clos/P4. 3pp.
BG4: Dunn, A., Haddon, M., Parma, AM. and Punt AE. International Review Panel report for the 2016 International Fisheries Stock Assessment workshop. MARAM/IWS/DEC16/General/7. 17pp.


BG1: Ross-Gillespie A. and Butterworth DS. Updated GLMM results for the South Coast penguin colony foraging data. FISHERIES/2019/NOV/SWG-PEL/27rev. Also referenced as MARAM/IWS/2019/PENG/P2. 12pp.
BG2: Ross-Gillespie A. and Butterworth DS. Results from GLMM analyses of the South Coast penguin colony chick condition data. FISHERIES/2019/NOV/SWG-PEL/33. Also referenced as MARAM/IWS/2019/PENG/P3. 5pp.
BG3: Sherley RB., Barham BJ., Barham PJ., Campbell KJ., Crawford RJM., de Blocq A., Grigg J., Le Guen C., Hagen C., Makhado AB., McInnes A., Meyer A., Morris T., Pichegru L., Steinfurth A., Upfold L., van Onselen M., Visagie J., Weller F. and Winker H. A Bayesian approach to understand the overall effect of the purse-seine fishing closures around African penguin colonies. FISHERIES/2019/NOV/SWG-PEL/32rev. Also referenced as MARAM/IWS/2019/PENG/P4.

Confidentiality precludes posting - the link is not available.

BG4: Butterworth DS. and Ross-Gillespie A. Is pseudo-replication biasing results from analyses from the island closure experiment which model individual penguin responses directly. MARAM/IWS/2019/PENG/P5. Also referenced as FISHERIES/2019/NOV/SWG-PEL/34. 10pp.
BG5: Sherley, RB., and Winker, H. Some observations on comparisons of fitting to the annual means and the observation-level data for the cases in MARAM/IWS/DEC19/Peng/P4 that support a positive effect of the island closures experiment on African penguins. MARAM/IWS/2019/PENG/WP3. 5pp.
BG6: Die, DJ., Punt, AE., Tiedemann, R., Waples R. and Wilberg, MJ. International Review Panel report for the 2019 International Fisheries Stock Assessment workshop. MARAM/IWS/2019/General/5. 18pp.


BG1: Butterworth, DS. On estimates of the impact of fishing from analyses of the island closure experiment which model individual penguin responses directly. DEFF report: FISHERIES/2020/JAN/SWG-PEL/08. 2pp.
BG2: Ross-Gillespie A. and Butterworth DS. Updated implementation of the Algorithm recommended by the Panel for the 2016 International Stock Assessment workshop for assessing whether or not to continue with the penguin island closure experiment. DEFF report: FISHERIES/2020/JAN/SWG-PEL/09rev. 17pp.
BG3: Sherley RB. Revisiting the key results in MARAM/IWS/2019/PENG/P4 in light of the 2019 Panel recommendations. FISHERIES/2020/JUL/SWG-PEL/53rev. 27pp.
BG4: Butterworth DS. A response to Sherley: FISHERIES/2020/JUL/SWG-PEL/53REV. DEFF report: FISHERIES/2020/AUG/SWG-PEL/82. 38pp.
BG5: Sherley RB. Some comments on FISHERIES/2020/JAN/SWG-PEL/08. DEFF report: FISHERIES/2020/AUG/SWG-PEL/83. 5pp.
BG6: Bergh M. Comments on ‘Revisiting the key results in MARAM/IWS/2019/PENG/P$ in light of the 2019 Panel recommendations (FISHERIES/2020/JUL/SWG-PEL/53REV) by Richard B Sherley’. DEFF report: FISHERIES/2020/AUG/SWG-PEL/84. 4pp.
BG7: Sherley RB. A response to Butterworth: FISHERIES/2020/AUG/SWG-PEL/82. DEFF report: FISHERIES/2020/SEP/SWG-PEL/85. 23pp.
BG8: Sherley RB. Some observations on comparisons of fitting to the annually aggregated and the individual data, this time using JAGS and for the cases considered in FISHERIES/2020/JUL/SWG-PEL/53REV. DEFF report: FISHERIES/2020/SEP/SWG-PEL/86. 4pp.
BG9: Sherley RB. A reply to Bergh: FISHERIES/2020/AUG/SWG-PEL/84. DEFF report: FISHERIES/2020/SEP/SWG-PEL/87. 18pp.
BG10: Sherley RB. Model selection results for the remaining penguin metrics that can currently be fitted using an individual data approach. FISHERIES/2020/SEP/SWG-PEL/89. 7pp.
BG11: de Moor CL. A simple summary of the penguin island closure analysis. DEFF report: FISHERIES/2020/SEP/SWG-PEL/95. 7pp.
BG12: Butterworth DS. Summary comments on analyses of the island closure experiment. DEFF report: FISHERIES/2020/SEP/SWG-PEL/96rev. 5pp.
BG13: Bergh M. Summary comments on the Penguin Island Closure Experiment. DEFF report: FISHERIES/2020/SEP/SWG-PEL/99. 2pp.
BG14: de Moor CL. A proposal for the future penguin island closures. DEFF report: FISHERIES/2020/OCT/SWG-PEL/102. 3pp.
BG15: Butterworth DS. A proposal for a basis to consider future island closures, taking account especially of the current results from the island closure experiment. DEFF report: FISHERIES/2020/OCT/SWG-PEL/103. 5pp.
BG16: Makhado A., McInnes A., Hagen C., Sherley R., Waller L., Pichegru L., Shannon L., Shaw K., Olds A., Ludynia K., Jarre A., Crawford R., Barham P., Masotla M., Carpenter-Kling T. and Stassen M. Recommendations for island closures around African Penguin colonies. DEFF report: FISHERIES/2020/OCT/SWG-PEL/105REV. 14pp.
BG17: Butterworth DS. A response to FISHERIES/2020/JUL/SWG-PEL/102. DEFF report: FISHERIES/2020/OCT/SWG-PEL/110. 6pp.
BG18: Butterworth DS. Response to FISHERIES/2020/JUL/SWG-PEL/105. DEFF report: FISHERIES/2020/OCT/SWG-PEL/111. 13pp.
BG19: Bergh M. Comments on FISHERIES/2020/SEP/SWG-PEL/105REV ‘Recommendations for the island closures around African Penguin colonies’. DEFF report: FISHERIES/2020/OCT/SWG-PEL/113. 11pp.
BG20: Sherley RB. Refitting the Western Cape chick survival model excluding the 8% chicks not monitored from hatching does not change the inference about the effect of the island closures. DEFF report: FISHERIES/2020/NOV/SWG-PEL/117rev. 6pp.


Past workshop panel reports