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- Bergenius Nord, Mikaela
(författare)
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Baltic Fisheries Assessment Working Group (WGBFAS)
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)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.
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- Bergenius Nord, Mikaela, et al.
(författare)
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Benchmark workshop on Pandalus stocks (WKPRAWN)
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Northern shrimp (Pandalus borealis) in divisions 3.a and 4.a East (Skagerrak and Kattegat and northern North Sea in the Norwegian Deep)An ensemble model was developed to incorporate uncertainty in natural mortality (SS3 model). A distribution of possible natural mortalities at age was constructed based on a suite of M life history and other type models. Three M scenarios were developed: a low, median and high M. An objective weighting approach was used based on model performance statistics and diagnostics to develop the final assessment. The reference points were estimated using a shortcut MSE approach testing a range of fishing mortalities and biomass thresholds in relation to virgin stock size (B0). Northern shrimp (Pandalus borealis) in subareas 1 and 2 (Northeast Arctic)For the Barents Sea stock, the accepted assessment model fell on SPiCT. The commercial CPUE used in the assessment was thoroughly investigated and standardized using a non-spatial model. A spatio-temporal modelling approach (sdmTMB) for the joint Norwegian/Russian Barents Sea Ecosystem Survey (BESS) was presented and compared to the design-based estimators currently used. There was some retrospective error on F/Fmsy but Based on the presented diagnostics, the reference model was considered adequate and acceptable. The standard approach for short-term forecasts and reference points was agreed.Flemish Cap shrimp (NAFO Div. 3M)There was limited progress on the Flemish Cap stock (pra.27.3M). An excellent long-term EU survey from 1988-present is available for the stock covering the period of the moratorium. This shows an increase from 2016 to 2019 with a subsequent decrease. Length-composition data are also available from the survey for this assessment. In future, it may be possible to explore an SS3 model for this stock given the partial and patchy nature of the available data.
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- Cardinale, Massimiliano, et al.
(författare)
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Workshop on ICES reference points (WKREF1)
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The ICES Workshop on ICES reference points (WKREF1) was tasked to provide a thorough review of the ICES reference points system as a basis to re-evaluate the process for estimating, updating and communicating reference points in the context of the ICES advice. As part of the preparation leading to WKREF1 a large database of the most recent assessment outputs for 78 Category 1 stocks were collated in the form `FLStock` objects, which formed the basis for several components of the presented analyses.
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- López, María-Eugenia, et al.
(författare)
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Lack of panmixia of Bothnian Bay vendace-Implications for fisheries management
- 2022
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Ingår i: Frontiers in marine science. - : Frontiers Media SA. - 2296-7745. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Overexploitation of fisheries is recognized as a major environmental and socioeconomic problem that threats biodiversity and ecosystem functioning. Inappropriate management policies of fish stocks have been applied as a consequence of inadequate characterization of subtle genetic structure in many fish species. In this study, we aim to assess the extent of genetic differentiation and structure of vendace (Coregonus albula) collected from eight locations in the Bothnian Bay, the northernmost part of the Baltic Sea. Specifically, we test if this species forms a single panmictic population or is divided into several genetically distinct units. We used restriction site-associated DNA sequencing (RAD-seq) to identify 21,792 SNPs based on 266 individuals. We identified a clear pattern of genetic differentiation between River Kalix and the other sampling locations, and a weak structuring between samples from Swedish and Finnish coast. Outlier analysis detected 41 SNPs putatively under divergent selection, mainly reflecting the divergence between River Kalix and the other samples. The outlier SNPs were located within or near 25 genes, including voltage-dependent calcium channel subunit alpha-2 (CACNA2D2), cadherin 26 (CDH26) and carbonic anhydrase 4-like (CA4) that have earlier been associated with salt-tolerance and salinity stress. Our study provides the first genome-wide perspective on genetic structuring of Baltic Sea vendace and rejects the hypothesis of panmixia in the Bothnian Bay. As such, our work demonstrates the power of RAD-sequencing to detect low but significant genetic structuring relevant for fisheries management.
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- Sundelöf, Andreas, et al.
(författare)
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Fisk- och skaldjursbestånd i hav och sötvatten 2021 : Resursöversikt
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I rapporten kan du ta del av bedömningen som görs av situationen för bestånd som regleras inom ramen för EU:s gemensamma fiskeripolitik (GFP). Bedömningarna baseras på det forskningssamarbete och den rådgivning som sker inom det Internationella Havsforskningsrådet (ICES). Sammantaget redovisas tillståndet för 107 bestånd av 48 fisk- och skaldjursarter.De bestånd som förvaltas nationellt baseras på de biologiska underlagen, och rådgivningen i huvudsak på den forskning och övervakning samt analys som bedrivs av Institutionen för akvatiska resurser vid Sveriges lantbruksuniversitet (SLU Aqua) samt yrkesfiskets rapportering.Rapporten är en beställning från Havs- och vattenmyndigheten (HaV) till Sveriges lantbruksuniversitet (SLU) och utgör ett viktigt kunskapsunderlag till myndighetens arbete. Den uppfyller de krav som finns inom EU:s gemensamma fiskeripolitik om att basera förvaltningen på bästa tillgängliga vetenskap. Denna rapport är också ett stöd till det arbete som beskrivs närmare i strategin för framtidens fiske och tillhörande handlingsplaner för vattenbruk, yrkes- och fritidsfiske som HaV och Jordbruksverket har tagit fram i dialog med fiskets och vattenbrukets intressenter.
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