Working Group for the Bay of Biscay and the Iberian Waters Ecoregion (WGBIE)
The ICES Working Group for the Bay of Biscay and the Iberian Waters Ecoregion (WGBIE) assesses the status of 23 stocks that are present within ICES divisions 3.a to 9.a . In effect, the majority of the stocks assessed by the working group are distributed across subareas 7, 8, and 9. WGBIE is tasked with conducting assessments of stock status using analytical models, surplus production models, or data-limited methods (DLS), to provide catch forecasts and a first draft of the ICES advice for 2023. For six stocks in categories 3–6, the advice was already provided in 2021 and remains valid for 2022 and 2023. After updates of stock information and the assessment, no advice revision was considered. For two Nephrops stocks (Functional Units 23–24 and 30), updates were provided on catch data with advice release delayed until October 2021, after the completion of the UWTV surveys used for the assessment. All other stocks were scheduled for regular advice release in June 2022 after updates to stock information and the stock assessment. Analytical assessments using age-structured models were conducted for the northern and southern stocks of megrim (meg.27.7b–k 8abd, meg.27.8c9a) four-spot megrim in Iberian Waters (ldb.27.8c9a), and sole in the Bay of Biscay (sol.27.8ab). Northern and southern hake (hke.27.3a46–8abd, hke.27.8c9a), northern black-bellied anglerfish stocks (ank.27.78abd), and both white anglerfish stocks (mon.27.78abd, mon.27.8c9a) were assessed using models that allow the use of length-based age-structured data. A surplus-production model was used to assess the southern black-bellied anglerfish (ank.27.8c9a) and the Nephrops stocks in FUs 25, 26–27, and 31. An analytical age–length structured model was used for sea bass in the Bay of Biscay. Length-based and survey trends-based methods were used to assess southern sole (sol.27.8c9a) and Nephrops in FUs 28–29. Two Nephrops stocks (FUs 23–24 and 30) are assessed using a bias-corrected UWTV survey abundance method. In total, seven WGBIE stocks were benchmarked this past year: northern white and black-bellied anglerfish, northern and southern hake, northern and southern megrim, and southern four-spot megrim. From these seven benchmarked species, two will require a future interbenchmark (IBPs) to improve assessment results and resolve outstanding issues, namely northern hake and southern megrim. A new analytical-based assessment for the southern stock of hake and northern black-bellied anglerfish stock was accepted during the WKANGHAKE benchmark workshop (ICES, 2022a), resulting in the upgrading of these stocks from category 3 (ICES, 2021e) to category 1. Now all four stocks benchmarked during WKANGHAKE are assessed using the Stock Synthesis (SS) approach (Methot, 2009; Methot and Wetzel, 2013). Among these four stocks, only northern hake was assessed using the SS framework before the recent benchmark. The assessment of the northern hake stock with SS, implemented since benchmarked in 2010 (ICES, 2010), took advantage of the 2022 workshop to further test and evaluate the model performance; as well as to identify, analyse, and resolve convergence issues after the integration of new information or parameters and data revisions. The three other stocks migrated from either an analytical approach (northern white anglerfish and southern hake) or length- and survey- trends-based assessments (northern black-bellied anglerfish) to the SS approach with the revision and integration of new reference points (ICES, 2021e). During the WKANGHAKE benchmark (ICES, 2022a), revised data were integrated and new reference points were estimated with most convergence issues resolved. All three new assessment models were validated and accepted during the WKANGHAKE benchmark (ICES, 2022a) and then used by WGBIE as the basis for advice this year. The new assessment model as well as the new reference points led to a different picture of the previous historical assessment. However, despite this and the change in assessment method for these three stocks as well as the updated assessment for the northern hake, the perception of these stocks remains unchanged. Three megrim stocks were also benchmarked, WKMEGRIM (ICES, 2022b), earlier this year with the main objective of migrating from an age-structured Bayesian-based (northern megrim) and XSA-based (southern megrims) models to standardized aged-based analytical a4a assessment approach (Millar and Jardim, 2019). Similar to the WKANGHAKE benchmark (ICES, 2022a), data revisions and re-estimation of reference points for each stock were made and most convergence issues were resolved during the WKMEGRIM benchmark (ICES, 2022b). Similar to the WKANGHAKE benchmarked stocks (ICES, 2022a), the recalculations of the reference points for the three megrim stocks led to a different picture of the previous historical assessment. However, despite the change in assessment approach, the perception of these stocks did not change. In 2020, the migration of assessment to TAF was initiated by ICES on some specific stocks. For WGBIE, the northern stock of hake and the Bay of Biscay sole stocks were chosen, and are now implementing TAF-based assessments. Contrary to 2020, this year WGBIE was informed that the collection of data from the commercial fishery and the research surveys for almost all stocks during 2021 was not affected despite the COVID-19 restrictions which are still implemented at varying degrees across member states. Most of the assessments were not affected although differences between values observed in 2020 and 2021, especially from scientific surveys, have been affected at different levels and can explain some changes in the assessment results of some stocks this year. This year, all the data requested by ICES had been uploaded to InterCatch ahead of the meeting and did not cause any delay in the assessment process of WGBIE stocks. For stocks with annual quotas, the total allowable catches (TACs) for 2022 were available as opposed to 2021 where some stocks were only able to provide provisional TAC for the first quarter due to Brexit (ICES, 2021e). The latter has also contributed to the shift in the management approach used for drafting the advice of all assessed northern stocks which are included in the EU multiannual management plan (EU MAP; EU, 2019). However, since there is no agreed shared management plan with the United Kingdom for these stocks, ICES provides advice for these stocks according to the ICES MSY approach since 2021 (ICES, 2021e). All forecasts and assessments are made following the ICES framework for category 1, 2, and 3 stocks (ICES, 2021a). In response to the continued disruption related to the COVID-19 pandemic, WGBIE decided to hold its assessment and advice meeting in 2022 online only. The online meetings have proven to be productive as all the planned Terms of Reference were covered. The structure of the report is set out as follows: section 1 presents a summary for each stock, discussing general issues and conclusions. Section 2 provides descriptions of the relevant fishing fleets and surveys used in the assessment of stocks. Sections 3 through 18 contain all the single-stock assessments.
Published under the auspices of the following ICES Steering Group or Committee