Working Group for the Bay of Biscay and the Iberian Waters Ecoregion (WGBIE)

Type Article
Date 2020
Language English
Author(s) ICES
Contributor(s) Abad Esther, Batts Luke, Cerviño Santiago, Drogou Mickael, Fifas Spyros, Garcia Dorleta, Gerritsen Hans, González Herraiz Isabel, Iriondo Ane, Kelly Eoghan, Lecomte Jean-Baptise, Mendes Hugo, Moura Teresa, Pennino M. Grazia, Pereira Bárbara, Readdy Lisa, Rodriguez- Ezpeleta Naiara, Sampedro Paz, Silva Cristina, Urtizberea Ijurco Agurtzane, Vermard YouenORCID, Vila Yolanda, Villanueva Ching-MariaORCID, Woillez MathieuORCID
Source ICES Scientific Reports/Rapports scientifiques du CIEM (2618-1371) (ICES), 2020 , Vol. 2 , N. 49 , P. 865p.
DOI 10.17895/ices.pub.6033
Abstract

The ICES Working Group for the Bay of Biscay and the Iberian Waters Ecoregion (WGBIE) as-sesses the status of 23 stocks distributed from ICES Divisions 3.a–4.a though to Subarea 9, mostly distributed in Subareas 7, 8 and 9. The group was tasked with conducting assessments of stock status for 14 stocks using analytical, forecast methods or trends indicators to provide catch fore-casts and a first draft of the ICES advice for 2021. For two of the Nephrops stocks updates were provided on catch data with the advice release delayed until October after the completion of the surveys used for the assessment. For the remaining 9 stocks not scheduled for advice this year, after the stock information update, no specific revision of the advice was proposed. The advice for these stocks, released in 2019, is valid for the years 2020 and 2021 or for 2020 to 2022.

Analytical assessments using age-structured models were conducted for the northern stock of white anglerfish, the northern and southern stocks of megrim, four-spot megrim in Iberian Waters and sole in the Bay of Biscay. The two hake stocks and one southern stock of anglerfish were assessed using models that allow the use of length-structured data (no age data). A surplus-production model, without age or length structure, was used to assess the second southern stock of anglerfish and an analytical age-length structure model was used for the European seabass in the Bay of Biscay. The state of stocks for which no analytical assessment could be performed was inferred from examination of catch, commercial LPUE or CPUE data and from survey information, where available.

The length-structured assessment for the southern stock of hake was rejected during the working group which resulted in the downgrading of the stock from Category 1 to 3 as an interim solution. This decision was also supported by the absence of clear guidelines on how to adjust fore-casts for advice when using the decision tree recommended by WKFORBIAS (ICES, 2020) for stocks with strong retrospective patterns. This year advice for the stock followed the 2 over 3-year rule based on survey and LPUE trends. A SPiCT model for the stock was explored for ref-erence points but some inconsistencies were found among biomass indices and the retrospective patterns were also problematic. Intersessional work (online workshop) to migrate assessment analyses to a Stock Synthesis model is planned before the end of the year.

Despite an ICES data call with a deadline of six weeks before the meeting, the recurrent late data submission to ICES for most stocks has occurred, worsened by the COVID-19 disruption. This delayed the process of having the data quality checked and the assessment completed before the start of the working group. This is an important matter of concerns for the working group members.

In response to the spread of COVID-19 virus, all ICES assessment and advice physical meetings were suspended and held remotely. The 2020 advice sheets for 13 stocks were abbreviated and will be released with advice released in 2019 as annex. A full advice sheet, however, was done for the southern hake due to the change in category of the stock.

The structure of the report is set out with section 1 presenting a summary for each stock, discuss-ing general issues and conclusions. Section 2 provides descriptions of the relevant fishing fleets and surveys used in the assessment of the stocks. Sections 3–18 contain the single stock assess-ments.

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