ICES IBPGCOD REPORT 2018 ICES ADVISORY COMMITTEE ICES CM 2018/ACOM:30 Report of the InterBenchmark Protocol on Greenland Cod (IBPGCod) 8–9 January 2018 Copenhagen, Denmark International Council for the Exploration of the Sea Conseil International pour l’Exploration de la Mer H. C. Andersens Boulevard 44–46 DK-1553 Copenhagen V Denmark Telephone (+45) 33 38 67 00 Telefax (+45) 33 93 42 15 www.ices.dk [email protected] Recommended format for purposes of citation: ICES. 2018. Report of the InterBenchmark Protocol on Greenland Cod (IBPGCod). ICES IBPGCod Report 2018 8–9 January 2018. Copenhagen, Denmark. ICES CM 2018/ ACOM:30. 205 pp. https://doi.org/10.17895/ices.pub.5266 The material in this report may be reused using the recommended citation. ICES may only grant usage rights of information, data, images, graphs, etc. of which it has owner- ship. For other third-party material cited in this report, you must contact the original copyright holder for permission. 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This document is the product of an Expert Group under the auspices of the International Council for the Exploration of the Sea and does not necessarily represent the view of the Council. © 2018 International Council for the Exploration of the Sea Contents Executive summary ................................................................................................................ 3 1 Introduction .................................................................................................................... 1 2 Description of the benchmark process ...................................................................... 2 3 Cod (Gadus morhua) in East Greenland .................................................................... 3 3.1 Stock ID and sub-stock structure (ToRs a.i) ..................................................... 3 Tagging studies .................................................................................................... 3 3.2 Life-history data (ToRs a.ii) ................................................................................ 3 Natural Mortality ................................................................................................. 3 Maturity ogive ...................................................................................................... 3 Weight (stock and catch)..................................................................................... 3 3.3 Fisheries-dependent and Fisheries-independent data (ToRs a.iii) ................ 4 3.3.1 Description of the surveys....................................................................... 4 3.3.2 Description of fisheries ............................................................................ 5 3.4 Assessment method and issues ......................................................................... 6 3.4.1 SAM ............................................................................................................ 6 3.5 Reference points (ToRs c) ................................................................................... 7 3.5.1 Recruitment ............................................................................................... 7 3.5.2 Blim estimation ........................................................................................... 7 3.5.3 EqSim settings ........................................................................................... 7 3.5.4 Stock recruitment relation, derived PA points and MSY simulations ................................................................................................ 8 MSY reference points (MSY Btrigger and FMSY) .................................................... 8 3.6 Short term projections (ToRs b) ......................................................................... 9 3.7 Future research and data requirements (ToRs d) ............................................ 9 4 Cod (Gadus morhua) inshore Greenland ................................................................. 10 4.1 Stock ID and sub-stock structure (ToRs a.i) ................................................... 10 4.2 Life-history data (ToRs a.ii) .............................................................................. 10 Natural Mortality ............................................................................................... 10 Maturity ogive .................................................................................................... 10 Weight (stock and catch)................................................................................... 11 4.3 Fisheries-dependent and Fisheries-independent data (ToRs a.iii) .............. 11 4.3.1 Description of the surveys..................................................................... 11 Age range in survey data .................................................................................. 11 Description of fisheries ..................................................................................... 12 Age range in catch data..................................................................................... 12 4.4 Assessment method and issues ....................................................................... 12 4.4.1 SAM .......................................................................................................... 12 4.5 Reference points (ToRs c) ................................................................................. 13 4.5.1 Recruitment ............................................................................................. 13 4.5.2 Blim estimation ......................................................................................... 13 4.5.3 EqSim settings ......................................................................................... 13 4.5.4 Stock recruitment relation, derived PA points and MSY simulations .............................................................................................. 14 MSY reference points (MSY Btrigger and FMSY) ......................................... 14 4.6 Short term projections (ToRs b) ....................................................................... 15 4.7 Future research and data requirements (ToRs d) .......................................... 15 5 Conclusions ................................................................................................................... 16 6 External Reviewers Report ......................................................................................... 17 6.1 Summary ............................................................................................................. 17 6.2 Analytical assessment and associated forecast of the West and East Greenland cod stocks ........................................................................................ 17 6.3 Assessment and forecast considerations specific to the East Greenland cod stock .......................................................................................... 17 6.4 Assessment and forecast considerations specific to the West Greenland cod stock .......................................................................................... 18 6.5 Assessment and forecast considerations common for both stocks ............. 19 6.5.1 Description of fisheries in recent years ............................................... 19 6.5.2 Stock components and stock delineation ............................................ 19 6.5.3 Survey and catch data ............................................................................ 20 7 References ..................................................................................................................... 22 Annex 1: List of participants ............................................................................................... 34 Annex 2: Agenda ................................................................................................................... 35 Annex 3: List of stock annexes ........................................................................................... 36 Annex 4: Working documents ............................................................................................ 37 Report of the InterBenchmark Protocol on Greenland Cod (IBPGCod) Executive summary The ICES InterBenchmark protocol for East Greenland and the inshore Greenland cod (IBPGreenlandCod) was held at ICES headquarters on 8 and 9 of January 2018. The meeting was chaired by Marie Storr-Paulsen, Denmark, with 10 participants from 5 nations (Greenland, Norway, Germany, Iceland and Denmark). External chair was Arved Staby, Norway and external experts Rasmus Nielsen and Bjarki Elvarsson, Ice- land. The InterBenchmark was mainly conducted to, if possible, upgrade the two Green- landic cod stock assessments from DLS assessment to a full analytic stock assessment (category 1 stocks). The meeting addressed issues regarding survey data, stock struc- ture and stock dynamics, weight and catch at age data from the commercial fishery, maturity ogive data, changes in fisheries and selection curves, as well as reference points and short term forecast settings. Specifically, issues around natural mortality from fish migrating at first spawning to Iceland and differences in mean weight at age between the Greenlandic survey on Paamiut and the German survey on Walter Herwig