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) hybrid meeting was held in Copenhagen and online from 3 to 11th of May 2023 and was chaired by Ching Villanueva (Fr) and Santiago Cerviño (Sp). The participants included 25 experts from 5 countries: France (FR), Ireland (IE), Portugal (PT), Spain (SP) and the United Kingdom (UK). WGBIE assesses the status of 23 stocks within ICES divisions 3.a to 9.a, mainly 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 2024. 

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 the WGBIE stocks. All forecasts and assessments are made following the ICES framework for category 1, 2, 3 and 5 stocks (ICES, 2023a). 

Three category 5 stocks which include the plaice, pollack and whiting were benchmarked (WKBMSYSPiCT2; ICES, 2023g) during the end of 2022. During this benchmark, none of each stock’s specific surplus-production in continuous time model (SPiCT; Pedersen and Berg, 2017) implemented was accepted. However, during this year’s meeting, the WGBIE supported the implementation of the ICES framework for category 3 stocks on the pollack (pol.27.89a) and whiting (whg.27.89a) stocks (ICES, 2023a) where the new ICES harvest control rules (HCRs) for categories 2 and 3 stocks (ICES, 2022a) was also applied. Each stock used a stock-specific estimated biomass index and length-based indicators (LBIs) to provide an MSY-based advice which were then submitted for review before the 2023 WGBIE Advice Drafting Group (ADGBBI) meeting. 

For the three remaining WGBIE category 5 stocks, the plaice (ple.27.89a) and the southern sea bass (bss.27.8c9a) stocks provided a precautionary approach landings advice for each of the years 2024 and 2025. The northern four-spot megrim (ldb.27.7b-k8abd), on the other hand, provided a precautionary approach catch advice (ICES, 2023a) last year which remains valid for this year (<867 t) and for each of the years 2024 and 2025 (ICES, 2022b). 

For the Nephrops in Functional Units (FUs) 2324 and 30, the stock assessments will be done in October after the completion of the 2023 UWTV surveys and data integration. Catch advices for the Nephrops stocks in FUs 2627 and 25 were provided in 2022 for each of the years 2023 and 2024. 

All the other stocks are scheduled for regular advice provision and release in June this year after updates to each of these stocks’ information and assessment, except for the northern four-spot megrim and the Nephorps in FUs 2627 and 30. After the updates of stock information and the assessment for all the other WGBIE stocks, no advice revision was considered.

Analytical assessments using age-structured models were conducted for the northern and southern stocks of megrim (meg.27.7b–k 8abd and 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 and hke.27.8c9a), northern black-bellied anglerfish stocks (ank.27.78abd), and both white anglerfish stocks (mon.27.78abd and 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 is used for the Bay of Biscay sea bass. Length-based and survey trends-based methods were used to assess southern sole (sol.27.8c9a) and Nephrops in FUs 28–29. Length-based and commercial LPUE trends-based methods were used to assess the pollack (pol.27.89a) and whiting (whg.27.89a) during the WGBIE meeting this year for potential upgrade considerations from category 5 to 3 stocks. Two Nephrops stocks (FUs 2324 and 30) are assessed using a bias-corrected UWTV survey abundance method (ICES, 2022b). 

Plaice, pollack, whiting were benchmarked this year. Pollack and whiting are proposed to be upgraded to Category 3 stocks, while plaice remains as a Category 5 stock. The Bay of Biscay sea bass (bss.27.8ab), which is a category 1 stock, is undergoing subsequent benchmarks where the stock identification workshop (WKBSEABASSID; ICES, 2023c) was held early 2023 which will be followed up by the data compilation workshop later this year and finally an update assessment workshop which is expected to occur in 2024. The Bay of Biscay sole (sol.27.8ab) will be benchmarked in 2024. WGBIE also proposes a benchmark for the southern anglerfish stocks (ank.27.8c9a and mon.27.8c9a), preferably in 2025.

In 2020, the migration of assessment to TAF (Transparent Assessment Framework) was initiated by ICES on some specific stocks. WGBIE have started this migration with two initial stocks (hke.27.3a46–8abd and sol.27.8ab). There is no new or additional TAF-based assessment model presented this year. WGBIE recognises the value of TAF-based assessments and encourages other WG stock’s experts to start and proceed with this migration, especially as a preparative and complementary step towards the imminent implementation of the RDBES-based stock assessments, replacing the InterCatch. 

This year, all WGBIE categories 2 and 3 stocks applied the new ICES technical guidelines for harvest control rules (HCRs) and stock assessments (ICES, 2022a; 2023a; e). For category 3 stocks, the application, when possible, of the new ‘rfb’ rule (Method 2.1 in ICES, 2022a) which replaced the 2-over-3 rule (ICES, 2012a; 2018a; 2019a) as the basis for the catch scenarios was applied with the exception of the Nephrops stock in FUs 2829, which used the previous procedures recommended by WKLIFE X for category 3 stocks on the basis that the advice should be provided with the most complete information (ICES, 2020a). 

All the planned Terms of References (ToRs), both generic and specific to WGBIE, were covered.