Abstract

The main objective of WGBFAS was to assess the status and produce a draft advice of the following stocks:

• Sole in Division 3.a, SDs 20–24 (catch advice)
• Cod in Kattegat SD 21 (catch advice)
• Cod in SDs 22–24 (catch advice)
• Cod in SDs 24–32 (catch advice)
• Herring in SDs 25–27, 28.2, 29 and 32 (catch advice)
• Herring in SD 28.1 (Gulf of Riga) (catch advice)
• Herring in SDs 30-31 (Gulf of Bothnia; catch advice)
• Sprat in SDs 22–32 (catch advice)
• Plaice in SDs 21–23 (catch advice)
• Plaice in SDs 24–32 (catch advice)
• Flounder in SDs 24–25 (stock status advice)
• Flounder in SDs 26+28 (stock status advice)
• Flounder in SDs 27+29–32 (stock status advice)
• Brill in SDs 22–32 (stock status advice)
• Dab in SDs 22–32 (stock status advice)

For these stocks, however, data were compiled and updated, and update assessments were conducted. The group adhered to the ICES spring 2020 approach to advice, developed because of the COVID-19 disruption. The meeting was consequently conducted online and abbreviated advice were produced for all stocks (for which an advice was requested), except Herring in SDs 30-31, Herring in SDs 25–27, 28.2, 29 and 32, and Sprat in SDs 22-32, as these stocks have beenbenchmarked since the last advice in 2019.

In the introductory chapter of this report the Working Group (WG), in agreement with the ToRs, considers and comments on the ecosystem and fisheries overviews, reviews the progress on benchmark processes, identifies the data needed for next year’s data call with some suggestions for improvements in the data call, and summarizes general and stock-specific research needs. The introduction further summarizes the work of other WGs relevant to WGBFAS, and the as-sessment methods used. Finally, the introduction presents a brief overview of each stock and quite extensively discusses the ecosystem considerations of the Baltic Sea and ecosystem changes that have been analytically considered in the stock assessments. The group thus completed all but one of the ToRs (to complete the productivity audit). This ToR will be completed intersessionally, before summer 2020.

The analytical models used for the stock assessments were XSA, SAM and SS3. For most flatfish (data limited stocks), CPUE trends from bottom-trawl surveys were used in the assessment (ex-cept plaice in SDs 24–25 for which relative SSB from SAM was used). For Herring in SDs 30-31, a data input issue was discovered during the meeting and the new benchmark assessment declared invalid. Therefore, the stock was downgraded from a category 3 to 5, and the advice based on the previous advice, applying the ICES advice rule for category 5 stocks.

Keywords

herring; Clupeidae (Family); sprat; Sprattus (Genus); Plaice fish; Brill; Baltic sea; brill; Scophthalmus rhombus; cod; Gadus morhua; dab; Limanda limanda; flounder; Platichthys spp.; Clupea harengus; plaice; Pleuronectes platessa; Sprattus sprattus turbot Scophthalmus maximus

Published in

ICES scientific reports
2020, number: 2:45
Publisher: International Council for the Exploration of the Sea

SLU Authors

• Bergenius Nord, Mikaela

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Ecology
Fish and Aquacultural Science


Publication identifier

DOI: https://doi.org/10.17895/ices.pub.6024

Permanent link to this page (URI)

https://res.slu.se/id/publ/123960