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Report, 2021

Benchmark workshop on herring (Clupea harengus) in the Gulf of Bothnia (WKCLuB 2021)

Cardinale, Massimiliano; Cerviño, Santiago; Gilljam, David; Hekim, Zeynep; Holmgren, Noél; Ianelli, Jim; Jounela, Pekka; Kaljuste, Olavi; Lilja, Juha; Lövgren, Johan; Orio, Alessandro; Pönni, Jukka; Pakarinen, Tapani; Raitaniemi, Jari;

Abstract

The assessment for the Gulf of Bothnia herring (SD 3031) in 2019 was not accepted by the Advice Drafting Group and was changed from category 1 to 3. The assessment was not accepted based on the poor retrospective diagnostics where the Mohn’s rho values were above 20% for SSB, F and recruitment. The aim for the Benchmark was to evaluate a new model, Stock Synthesis (SS3) as a candidate for the assessment of Gulf of Bothnia Herring SD30–31 in order to minimize the retrospective pattern previously observed. Following the path of the Benchmark data related issues were revealed. This led to a situation that the benchmark was prolonged one year in order to correct the data related issues. Apart from a misspecification in the model about how the trapnet index was used (abundance index vs. biomass index), the data problem had been related to the acoustic survey. The acoustic survey index used in the assessment was thoroughly examined by the Baltic international fish survey working group (WGBIFS) in a meeting in December 2020. A number of model runs (six prior to meeting, and an additional 16 during the benchmark) were conducted for evaluation at this benchmark. The analysis presented extensive diagnostic tests including the standard ICES criterion related to retrospective patterns. This was considered an enhancement over using one method for accepting or rejecting an assessment. It was noted that the final retrospective pattern had low and acceptable values of Mohn’s rho. In general, the benchmark using the stock synthesis platform with the settings specified during the benchmark are considered acceptable for assessment and advice and have features that should ensure stability as new data are added (e.g. selectivity is assumed to be constant over time).

Published in

ICES scientific reports

2021, number: 3:9
Publisher: International Council for the Exploration of the Sea

Authors' information

Swedish University of Agricultural Sciences, Department of Aquatic Resources
Cerviño, Santiago
Spanish Institute of Oceanography
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Ianelli, Jim
National Oceanic and Atmospheric Administration (NOAA)
Jounela, Pekka
Natural Resources Institute Finland (LUKE)
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Lilja, Juha
Natural Resources Institute Finland (LUKE)
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Pönni, Jukka
Natural Resources Institute Finland (LUKE)
Pakarinen, Tapani
Natural Resources Institute Finland (LUKE)
Raitaniemi, Jari
Natural Resources Institute Finland (LUKE)

UKÄ Subject classification

Fish and Aquacultural Science

Publication Identifiers

DOI: https://doi.org/10.17895/ices.pub.5989

URI (permanent link to this page)

https://res.slu.se/id/publ/110973