Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2)

Alessandro Orio, Anastasiia Karpushevskaia, Anders Nielsen, Andreas Sundelöf, Casper Willestofte Berg, Christoffer Moesgaard Albertsen, Conrad Stralka, Francesca Vitale, Franziska Schade, Fritz Köster, Hans Jakob Olesen, Harry Vincent Strehlow, Hege Sande, Henrik Mosegaard, Jan Horbowy, Jane Behrens, Joakim Hjelm, Johan Lövgren, Jonna Tomkiewicz, Karin HüssyKate McQueen, Keith Brander, Kåre Nolde Nielsen, Marc Simon Weltersbach, Marcin Ruciński, Margit Eero, Maria Pierce, Marie Plambech Ryberg, Marie Storr-Paulsen, Maris Plikshs, Massimiliano Cardinale, Meaghan Bryan, Michael Andersen, Michele Casini, Mikaela Bergenius, Monica Mion, Nils Höglund, Sebastian Linke, Sofia Carlshamre, Staffan Larsson, Stefanie Haase, Uwe Krumme, Verena Trenkel, Vladlena Gertseva, Viktoriia Amosova, Xochitl Cormon, Yvette Heimbrand

Research output: Book/ReportReport

28 Downloads (Pure)

Abstract

The ICES Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2) met at ICES Headquarters in Copenhagen, Denmark on 4–8 February 2019, following a data evaluation workshop (Chair Johan Lövgren) and several preparatory web conference meetings. The meeting, cochaired by Meaghan Bryan, USA (External Chair) and Michele Casini, Sweden (ICES Chair), was attended by two invited external experts, Vladlena Gertseva, USA, and Verena Trenkel, France, and 47 participants from 10 countries. Participants represented a diversity of groups including industry, NGOs, managers, and scientists.
The objectives of WKBALTCOD2 were to evaluate the appropriateness of the data and the assessment methods to determine stock status for the Western Baltic cod (SD 22-24) and the Eastern Baltic cod (SD 24-32) stocks, evaluate the short-term forecasting methods, re-examine and update the reference points, and update the stock annex as appropriate to these stocks.
The workshop started with a group discussion of data issues and decisions that were integral to both assessments. Subsequent, stock-specific discussions were held in smaller subgroups and the main results and conclusions were presented in plenary. Around 15–20 persons, together with at least one external reviewer/co-chair, participated in each of the subgroups.
A single modelling approach, the state-space stock assessment model (SAM), was presented for Western Baltic cod. This model has been used previously to determine stock status of Western Baltic cod and the panel agreed that this model should be used for the current assessment. The main issues that emerged and were addressed during the workshop for this stock were stock mixing in SD 24, the inclusion of new recreational data from Sweden and Denmark, the inclusion of a German pound-net survey index of age-0 fish in the assessment model, the extension of the time-series of the assessment back in time, and the update of reference points. Future efforts should be made to update the mixing proportion of Eastern and Western Baltic cod in SD 24 by length and season, and continue improving the stock splitting methods and the geographical coverage of the samples.
An analytical quantitative assessment had been lacking since 2014 for the Eastern Baltic cod stock. The key issues addressed during the benchmark included how to best account for changes in productivity (e.g. growth, mortality, maturity) in the assessment model, stock splitting in SD 24, the use of age–length keys in the assessment, and ageing error and bias. Stock assessment models using Stock Synthesis and the stochastic surplus production model (SPiCT) were put forward for the benchmark as two possible model candidates. The panel agreed that the Stock Synthesis model assuming time-varying growth, natural mortality, and maturity to account for changes in productivity was acceptable to provide scientific advice, while the SPiCT model should be maintained as an alternative approach. The accepted model exhibited some residual patterns that were likely due to assuming that ages were precisely known. Stock Synthesis can accommodate an ageing error matrix to account for precision and bias. Ageing error and bias statistics should be developed and thoroughly reviewed for the next benchmark. Additionally, future work should focus on improving the growth estimates, which will allow a more precise separation between growth and natural mortality. The Stock Synthesis model would also benefit from information on sample size associated with length distributions of commercial catches. Estimates of fishing mortality compatible with a precautionary FMSY was not attainable for this stock, therefore probabilistic forecasts with Markov chain Monte Carlo methods were proposed to be used instead.
Original languageEnglish
PublisherInternational Council for the Exploration of the Sea (ICES)
Number of pages314
DOIs
Publication statusPublished - 2019
SeriesICES Scientific Report
Number9
Volume1
ISSN2618-1371

Cite this

Orio, A., Karpushevskaia, A., Nielsen, A., Sundelöf, A., Berg, C. W., Albertsen, C. M., ... Heimbrand, Y. (2019). Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2). International Council for the Exploration of the Sea (ICES). ICES Scientific Report, No. 9, Vol.. 1 https://doi.org/10.17895/ices.pub.4984
Orio, Alessandro ; Karpushevskaia, Anastasiia ; Nielsen, Anders ; Sundelöf, Andreas ; Berg, Casper Willestofte ; Albertsen, Christoffer Moesgaard ; Stralka, Conrad ; Vitale, Francesca ; Schade, Franziska ; Köster, Fritz ; Olesen, Hans Jakob ; Strehlow, Harry Vincent ; Sande, Hege ; Mosegaard, Henrik ; Horbowy, Jan ; Behrens, Jane ; Hjelm, Joakim ; Lövgren, Johan ; Tomkiewicz, Jonna ; Hüssy, Karin ; McQueen, Kate ; Brander, Keith ; Nielsen, Kåre Nolde ; Weltersbach, Marc Simon ; Ruciński, Marcin ; Eero, Margit ; Pierce, Maria ; Plambech Ryberg, Marie ; Storr-Paulsen, Marie ; Plikshs, Maris ; Cardinale, Massimiliano ; Bryan, Meaghan ; Andersen, Michael ; Casini, Michele ; Bergenius, Mikaela ; Mion, Monica ; Höglund, Nils ; Linke, Sebastian ; Carlshamre, Sofia ; Larsson, Staffan ; Haase, Stefanie ; Krumme, Uwe ; Trenkel, Verena ; Gertseva, Vladlena ; Amosova, Viktoriia ; Cormon, Xochitl ; Heimbrand, Yvette. / Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2). International Council for the Exploration of the Sea (ICES), 2019. 314 p. (ICES Scientific Report; No. 9, Vol. 1).
@book{dcc324cf0f1f499e869ce969229a4a7a,
title = "Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2)",
abstract = "The ICES Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2) met at ICES Headquarters in Copenhagen, Denmark on 4–8 February 2019, following a data evaluation workshop (Chair Johan L{\"o}vgren) and several preparatory web conference meetings. The meeting, cochaired by Meaghan Bryan, USA (External Chair) and Michele Casini, Sweden (ICES Chair), was attended by two invited external experts, Vladlena Gertseva, USA, and Verena Trenkel, France, and 47 participants from 10 countries. Participants represented a diversity of groups including industry, NGOs, managers, and scientists. The objectives of WKBALTCOD2 were to evaluate the appropriateness of the data and the assessment methods to determine stock status for the Western Baltic cod (SD 22-24) and the Eastern Baltic cod (SD 24-32) stocks, evaluate the short-term forecasting methods, re-examine and update the reference points, and update the stock annex as appropriate to these stocks. The workshop started with a group discussion of data issues and decisions that were integral to both assessments. Subsequent, stock-specific discussions were held in smaller subgroups and the main results and conclusions were presented in plenary. Around 15–20 persons, together with at least one external reviewer/co-chair, participated in each of the subgroups. A single modelling approach, the state-space stock assessment model (SAM), was presented for Western Baltic cod. This model has been used previously to determine stock status of Western Baltic cod and the panel agreed that this model should be used for the current assessment. The main issues that emerged and were addressed during the workshop for this stock were stock mixing in SD 24, the inclusion of new recreational data from Sweden and Denmark, the inclusion of a German pound-net survey index of age-0 fish in the assessment model, the extension of the time-series of the assessment back in time, and the update of reference points. Future efforts should be made to update the mixing proportion of Eastern and Western Baltic cod in SD 24 by length and season, and continue improving the stock splitting methods and the geographical coverage of the samples. An analytical quantitative assessment had been lacking since 2014 for the Eastern Baltic cod stock. The key issues addressed during the benchmark included how to best account for changes in productivity (e.g. growth, mortality, maturity) in the assessment model, stock splitting in SD 24, the use of age–length keys in the assessment, and ageing error and bias. Stock assessment models using Stock Synthesis and the stochastic surplus production model (SPiCT) were put forward for the benchmark as two possible model candidates. The panel agreed that the Stock Synthesis model assuming time-varying growth, natural mortality, and maturity to account for changes in productivity was acceptable to provide scientific advice, while the SPiCT model should be maintained as an alternative approach. The accepted model exhibited some residual patterns that were likely due to assuming that ages were precisely known. Stock Synthesis can accommodate an ageing error matrix to account for precision and bias. Ageing error and bias statistics should be developed and thoroughly reviewed for the next benchmark. Additionally, future work should focus on improving the growth estimates, which will allow a more precise separation between growth and natural mortality. The Stock Synthesis model would also benefit from information on sample size associated with length distributions of commercial catches. Estimates of fishing mortality compatible with a precautionary FMSY was not attainable for this stock, therefore probabilistic forecasts with Markov chain Monte Carlo methods were proposed to be used instead.",
author = "Alessandro Orio and Anastasiia Karpushevskaia and Anders Nielsen and Andreas Sundel{\"o}f and Berg, {Casper Willestofte} and Albertsen, {Christoffer Moesgaard} and Conrad Stralka and Francesca Vitale and Franziska Schade and Fritz K{\"o}ster and Olesen, {Hans Jakob} and Strehlow, {Harry Vincent} and Hege Sande and Henrik Mosegaard and Jan Horbowy and Jane Behrens and Joakim Hjelm and Johan L{\"o}vgren and Jonna Tomkiewicz and Karin H{\"u}ssy and Kate McQueen and Keith Brander and Nielsen, {K{\aa}re Nolde} and Weltersbach, {Marc Simon} and Marcin Ruciński and Margit Eero and Maria Pierce and {Plambech Ryberg}, Marie and Marie Storr-Paulsen and Maris Plikshs and Massimiliano Cardinale and Meaghan Bryan and Michael Andersen and Michele Casini and Mikaela Bergenius and Monica Mion and Nils H{\"o}glund and Sebastian Linke and Sofia Carlshamre and Staffan Larsson and Stefanie Haase and Uwe Krumme and Verena Trenkel and Vladlena Gertseva and Viktoriia Amosova and Xochitl Cormon and Yvette Heimbrand",
year = "2019",
doi = "10.17895/ices.pub.4984",
language = "English",
series = "ICES Scientific Report",
publisher = "International Council for the Exploration of the Sea (ICES)",
number = "9",

}

Orio, A, Karpushevskaia, A, Nielsen, A, Sundelöf, A, Berg, CW, Albertsen, CM, Stralka, C, Vitale, F, Schade, F, Köster, F, Olesen, HJ, Strehlow, HV, Sande, H, Mosegaard, H, Horbowy, J, Behrens, J, Hjelm, J, Lövgren, J, Tomkiewicz, J, Hüssy, K, McQueen, K, Brander, K, Nielsen, KN, Weltersbach, MS, Ruciński, M, Eero, M, Pierce, M, Plambech Ryberg, M, Storr-Paulsen, M, Plikshs, M, Cardinale, M, Bryan, M, Andersen, M, Casini, M, Bergenius, M, Mion, M, Höglund, N, Linke, S, Carlshamre, S, Larsson, S, Haase, S, Krumme, U, Trenkel, V, Gertseva, V, Amosova, V, Cormon, X & Heimbrand, Y 2019, Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2). ICES Scientific Report, no. 9, vol. 1, International Council for the Exploration of the Sea (ICES). https://doi.org/10.17895/ices.pub.4984

Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2). / Orio, Alessandro; Karpushevskaia, Anastasiia; Nielsen, Anders; Sundelöf, Andreas; Berg, Casper Willestofte; Albertsen, Christoffer Moesgaard; Stralka, Conrad; Vitale, Francesca; Schade, Franziska; Köster, Fritz; Olesen, Hans Jakob; Strehlow, Harry Vincent; Sande, Hege; Mosegaard, Henrik; Horbowy, Jan; Behrens, Jane; Hjelm, Joakim; Lövgren, Johan; Tomkiewicz, Jonna; Hüssy, Karin; McQueen, Kate; Brander, Keith ; Nielsen, Kåre Nolde; Weltersbach, Marc Simon; Ruciński, Marcin; Eero, Margit; Pierce, Maria; Plambech Ryberg, Marie; Storr-Paulsen, Marie; Plikshs, Maris; Cardinale, Massimiliano; Bryan, Meaghan; Andersen, Michael; Casini, Michele; Bergenius, Mikaela ; Mion, Monica; Höglund, Nils; Linke, Sebastian; Carlshamre, Sofia; Larsson, Staffan; Haase, Stefanie; Krumme, Uwe; Trenkel, Verena; Gertseva, Vladlena; Amosova, Viktoriia; Cormon, Xochitl; Heimbrand, Yvette.

International Council for the Exploration of the Sea (ICES), 2019. 314 p. (ICES Scientific Report; No. 9, Vol. 1).

Research output: Book/ReportReport

TY - RPRT

T1 - Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2)

AU - Orio, Alessandro

AU - Karpushevskaia, Anastasiia

AU - Nielsen, Anders

AU - Sundelöf, Andreas

AU - Berg, Casper Willestofte

AU - Albertsen, Christoffer Moesgaard

AU - Stralka, Conrad

AU - Vitale, Francesca

AU - Schade, Franziska

AU - Köster, Fritz

AU - Olesen, Hans Jakob

AU - Strehlow, Harry Vincent

AU - Sande, Hege

AU - Mosegaard, Henrik

AU - Horbowy, Jan

AU - Behrens, Jane

AU - Hjelm, Joakim

AU - Lövgren, Johan

AU - Tomkiewicz, Jonna

AU - Hüssy, Karin

AU - McQueen, Kate

AU - Brander, Keith

AU - Nielsen, Kåre Nolde

AU - Weltersbach, Marc Simon

AU - Ruciński, Marcin

AU - Eero, Margit

AU - Pierce, Maria

AU - Plambech Ryberg, Marie

AU - Storr-Paulsen, Marie

AU - Plikshs, Maris

AU - Cardinale, Massimiliano

AU - Bryan, Meaghan

AU - Andersen, Michael

AU - Casini, Michele

AU - Bergenius, Mikaela

AU - Mion, Monica

AU - Höglund, Nils

AU - Linke, Sebastian

AU - Carlshamre, Sofia

AU - Larsson, Staffan

AU - Haase, Stefanie

AU - Krumme, Uwe

AU - Trenkel, Verena

AU - Gertseva, Vladlena

AU - Amosova, Viktoriia

AU - Cormon, Xochitl

AU - Heimbrand, Yvette

PY - 2019

Y1 - 2019

N2 - The ICES Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2) met at ICES Headquarters in Copenhagen, Denmark on 4–8 February 2019, following a data evaluation workshop (Chair Johan Lövgren) and several preparatory web conference meetings. The meeting, cochaired by Meaghan Bryan, USA (External Chair) and Michele Casini, Sweden (ICES Chair), was attended by two invited external experts, Vladlena Gertseva, USA, and Verena Trenkel, France, and 47 participants from 10 countries. Participants represented a diversity of groups including industry, NGOs, managers, and scientists. The objectives of WKBALTCOD2 were to evaluate the appropriateness of the data and the assessment methods to determine stock status for the Western Baltic cod (SD 22-24) and the Eastern Baltic cod (SD 24-32) stocks, evaluate the short-term forecasting methods, re-examine and update the reference points, and update the stock annex as appropriate to these stocks. The workshop started with a group discussion of data issues and decisions that were integral to both assessments. Subsequent, stock-specific discussions were held in smaller subgroups and the main results and conclusions were presented in plenary. Around 15–20 persons, together with at least one external reviewer/co-chair, participated in each of the subgroups. A single modelling approach, the state-space stock assessment model (SAM), was presented for Western Baltic cod. This model has been used previously to determine stock status of Western Baltic cod and the panel agreed that this model should be used for the current assessment. The main issues that emerged and were addressed during the workshop for this stock were stock mixing in SD 24, the inclusion of new recreational data from Sweden and Denmark, the inclusion of a German pound-net survey index of age-0 fish in the assessment model, the extension of the time-series of the assessment back in time, and the update of reference points. Future efforts should be made to update the mixing proportion of Eastern and Western Baltic cod in SD 24 by length and season, and continue improving the stock splitting methods and the geographical coverage of the samples. An analytical quantitative assessment had been lacking since 2014 for the Eastern Baltic cod stock. The key issues addressed during the benchmark included how to best account for changes in productivity (e.g. growth, mortality, maturity) in the assessment model, stock splitting in SD 24, the use of age–length keys in the assessment, and ageing error and bias. Stock assessment models using Stock Synthesis and the stochastic surplus production model (SPiCT) were put forward for the benchmark as two possible model candidates. The panel agreed that the Stock Synthesis model assuming time-varying growth, natural mortality, and maturity to account for changes in productivity was acceptable to provide scientific advice, while the SPiCT model should be maintained as an alternative approach. The accepted model exhibited some residual patterns that were likely due to assuming that ages were precisely known. Stock Synthesis can accommodate an ageing error matrix to account for precision and bias. Ageing error and bias statistics should be developed and thoroughly reviewed for the next benchmark. Additionally, future work should focus on improving the growth estimates, which will allow a more precise separation between growth and natural mortality. The Stock Synthesis model would also benefit from information on sample size associated with length distributions of commercial catches. Estimates of fishing mortality compatible with a precautionary FMSY was not attainable for this stock, therefore probabilistic forecasts with Markov chain Monte Carlo methods were proposed to be used instead.

AB - The ICES Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2) met at ICES Headquarters in Copenhagen, Denmark on 4–8 February 2019, following a data evaluation workshop (Chair Johan Lövgren) and several preparatory web conference meetings. The meeting, cochaired by Meaghan Bryan, USA (External Chair) and Michele Casini, Sweden (ICES Chair), was attended by two invited external experts, Vladlena Gertseva, USA, and Verena Trenkel, France, and 47 participants from 10 countries. Participants represented a diversity of groups including industry, NGOs, managers, and scientists. The objectives of WKBALTCOD2 were to evaluate the appropriateness of the data and the assessment methods to determine stock status for the Western Baltic cod (SD 22-24) and the Eastern Baltic cod (SD 24-32) stocks, evaluate the short-term forecasting methods, re-examine and update the reference points, and update the stock annex as appropriate to these stocks. The workshop started with a group discussion of data issues and decisions that were integral to both assessments. Subsequent, stock-specific discussions were held in smaller subgroups and the main results and conclusions were presented in plenary. Around 15–20 persons, together with at least one external reviewer/co-chair, participated in each of the subgroups. A single modelling approach, the state-space stock assessment model (SAM), was presented for Western Baltic cod. This model has been used previously to determine stock status of Western Baltic cod and the panel agreed that this model should be used for the current assessment. The main issues that emerged and were addressed during the workshop for this stock were stock mixing in SD 24, the inclusion of new recreational data from Sweden and Denmark, the inclusion of a German pound-net survey index of age-0 fish in the assessment model, the extension of the time-series of the assessment back in time, and the update of reference points. Future efforts should be made to update the mixing proportion of Eastern and Western Baltic cod in SD 24 by length and season, and continue improving the stock splitting methods and the geographical coverage of the samples. An analytical quantitative assessment had been lacking since 2014 for the Eastern Baltic cod stock. The key issues addressed during the benchmark included how to best account for changes in productivity (e.g. growth, mortality, maturity) in the assessment model, stock splitting in SD 24, the use of age–length keys in the assessment, and ageing error and bias. Stock assessment models using Stock Synthesis and the stochastic surplus production model (SPiCT) were put forward for the benchmark as two possible model candidates. The panel agreed that the Stock Synthesis model assuming time-varying growth, natural mortality, and maturity to account for changes in productivity was acceptable to provide scientific advice, while the SPiCT model should be maintained as an alternative approach. The accepted model exhibited some residual patterns that were likely due to assuming that ages were precisely known. Stock Synthesis can accommodate an ageing error matrix to account for precision and bias. Ageing error and bias statistics should be developed and thoroughly reviewed for the next benchmark. Additionally, future work should focus on improving the growth estimates, which will allow a more precise separation between growth and natural mortality. The Stock Synthesis model would also benefit from information on sample size associated with length distributions of commercial catches. Estimates of fishing mortality compatible with a precautionary FMSY was not attainable for this stock, therefore probabilistic forecasts with Markov chain Monte Carlo methods were proposed to be used instead.

U2 - 10.17895/ices.pub.4984

DO - 10.17895/ices.pub.4984

M3 - Report

T3 - ICES Scientific Report

BT - Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2)

PB - International Council for the Exploration of the Sea (ICES)

ER -

Orio A, Karpushevskaia A, Nielsen A, Sundelöf A, Berg CW, Albertsen CM et al. Benchmark Workshop on Baltic Cod Stocks (WKBALTCOD2). International Council for the Exploration of the Sea (ICES), 2019. 314 p. (ICES Scientific Report; No. 9, Vol. 1). https://doi.org/10.17895/ices.pub.4984