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This year the group changed its name to Working Group on Acoustic and Egg Surveys for small pelagic fish in NE Atlantic (WGACEGG). WGACEGG coordinates, assesses and quality controls acoustic and daily egg production (DEPM) surveys of several pelagic stocks in ICES areas 6-9. During three 2020 WGACEGG meetings, results of three DEPM surveys, three spring/summer acoustic surveys and all six autumn surveys were presented. Implications of the cancellation of three surveys (SAREVA and PELACUS (Spain)) and PELGAS (France) were also discussed, as were possible mitigations to minimize the effects on the relevant stock assessments. No concerns were raised about the surveys that took place. The results from the DEPM survey for sardine in 9a could not be provided until December, as COVID-19 had restricted laboratory access. WGACEGG also met with members of the Working Group on Southern Horse Mackerel, Anchovy, and Sardine (WGHANSA) to present the results from the 2020 Portuguese (PELAGO) acoustic survey in advance of the June assessment meeting. The working groups discussed the implications of PELAGO using a different vessel and of the earlier timing (compared to the timeseries) on the sardine and anchovy indices. The joint meeting also identified which surveys were at risk of being cancelled because of COVID-19 and discussed possible mitigations. Biomass estimates for both sardine and anchovy in division 9a were higher than observed in recent years as confirmed by both acoustic and DEPM surveys; DEPM derived Bay of Biscay anchovy spawning stock biomass was the highest on record although the number of recruits in the Bay of Biscay observed later in autumn did not reflect this increase. However, this was at least partly due to a northwards expansion into the English Channel where Bay of Biscay juveniles were found for the first time; sardine biomass in the Bay of Biscay from all available surveys suggested slightly lower values than the long-term average; in the English Channel sardine biomass was the second highest in the time-series; sprat biomass in the English Channel was similar to those observed in the last few years; herring biomass in the Celtic Sea had increased from 2019 but was still very low; Horse mackerel south and west of Ireland continued a three-year declining trend in biomass whereas boarfish biomass in the same area more than doubled. The group updated the grid map database and the joint analyses of the ecological drivers of pelagic species distributions within their ecosystems. Two ICES TIMES reports will be published soon; the acoustic report has been accepted and the DEPM report is currently under revision. WGACEGG participants also contributed to several peer reviewed publications in 2020 and more are under revision. WGACEGG and the Working Group on Acoustic Trawl Data Portal Governance (WGAcousticGov) agreed to continue the move towards using the ICES trawl acoustic database as the primary survey data repository. Progress on other collaborative activities was discussed, including with WGSPF (Small Pelagic Fish) and, specifically, a WGACEGG-led theme session for the 2022 SPF Symposium.

The goal of a benchmark is consensus agreement on an assessment methodology that is to be used in future update assessments. This assessment methodology can be an analytical assessment, but can also be non-analytical, for instance based on trends in an assessment or in a selected set of (survey) indicators, with or without forecasts. The result will be the 'best available' method that ICES advice will be based on. WKWEST 2021 dealt with the following stocks: Sardine (Sardina pilchardus) in Subarea 7 (southern Celtic Seas, and the English Channel); Pollack (Pollachius pollachius) in subareas 6-7 (Celtic Seas and the English Channel); Red gurnard (Chelidonichthys cuculus) in subareas 3–8 (Northeast Atlantic); Plaice (Pleuronectes platessa) in divisions 7.h–k (Celtic Sea South, southwest of Ireland); Sole (Solea solea) in divisions 8.c and 9.a (Cantabrian Sea and Atlantic Iberian waters).

Plusieurs analyses sont proposées dans ce cadre et en réponse à la saisine : 1) un bilan de l’effort de pêche des navires français en zone CIEM VIII aux engins sensibles aux captures accidentelles sur les périodes hivernales de 2019 à 2021 (entre le 1er décembre et le 31 mars), 2) une cartographie de l’effort de pêche aux engins sensibles sur ces mêmes périodes, 3) une analyse de l’évolution de l’activité halieutique française et étrangère entre 2010 et 2020 avec une attention particulière portée aux périodes hivernales et aux engins sensibles, 4) des premiers éléments sur la problématiques de l’estimation des métriques d’effort de pêche des engins sensibles en particulier des filets, 5) une actualisation de la typologie des navires pratiquant le filet dans la zone CIEM VIII durant les périodes hivernales étendue 2019 et 2020 (entre le 1er décembre et le 31 mai) et enfin 6) une analyse de l’évolution de l’abondance des espèces – proies des cétacés. Selon le niveau de précision disponible dans les données. Par exemple en l’absence de géolocalisation généralisée des navires de pêche, la cartographie des activités de pêche des navires français de moins de 12 mètre n’a pu être réalisée qu’au niveau des rectangles statistiques ICES, niveau insuffisant pour une bonne représentation de l’activité de pêche de ces navires.

The initial focus of the PELGAS integrated survey was to assess the small pelagic fish biomass in the Bay of Biscay in springtime, for fisheries management purposes. Sampling has been extended to produce long-term time-series of spatially-explicit data and indices, describing the main pelagic ecosystem components: hydrology, phytoplankton, mesozooplankton, fish and megafauna. A collaborative analysis of these datasets has brought new insights on the Bay of Biscay pelagic ecosystem summarized here. New results on single ecosystem components include an analysis of water samples to groundtruth the results of an ocean color algorithm aiming at detecting phytoplanktonic coccolithophores. New insights on mesozooplankton spatio-temporal distribution and energy content have been derived from the analysis of net samples. Adult anchovy and sardine energy content have been studied along a latitudinal gradient, and across different age stages. Changing patterns in the relative abundance of marine megafauna have been evidenced at a community level. Cross-ecosystem component studies are also presented. Actual dates of the annual survey have been corrected, with respect to a surface temperature climatology, allowing for an improved interpretation of anchovy and sardine spawning. Spring habitats of small pelagic fish communities in the Bay of Biscay have been characterised. Fluctuations in habitat preferences of five mobile top predators species have been assessed. Predation of cetaceans on small pelagic fish has been investigated, based on stomach contents. The spatial structure of the ecosystem has been characterised, to map consistent ecosystem seascapes and study their variability in time. Dominant ecological processes in the Bay of Biscay have been identified based on series of potential pelagic ecosystem indicators derived from the survey, and the effects of external forcing on the ecosystem dynamics tested. Perspectives for the survey are discussed in the context of the European Marine Strategy Framework Directive and the Common Fisheries Policy.

The PELGAS sea cruises aim at monitoring the Bay of Biscay pelagic ecosystem, in order to provide scientific data for the implementing of an ecosystemic management of Biscay living ressources. The spatial and temporal dynamics of small pelagic fish populations are specifically monitored, with a focus on anchovy populations. The cruise hence takes place in spring, during anchovy spawning, to allow for the assessment of both eggs and adult stages. The PELGAS ecosystemic cruise aims at collecting data at each level of the Biscay trophic chain. Data are collected continuously along parallel transects covering the whole Bay of Biscay, in order to thoroughly characterize the horizontal and vertical structures of the pelagic ecosystem. Multibeam and multifrequency echosounders provide real time information on the spatial patterns and abundance of pelagic organisms ranging from plankton to fish. Simultaneously, a Continuous Fisg Egg Sampler provide complementary data on small pelagic fish eggs. The presence and abundance of seabirds and marine mammals are also continuously recorded. Acoustic targets are punctually identified by fishing (pelagic trawling and plankton nets) and/or using video (trawl camera, Remotely Operated Vehicle EROC, plankton video profiler). CTD stations are actually performed over the whole Bay of Biscay to provide hydrological information. In situ measurements are compared to satellite and hydrodynamic models outputs. This documents describes the sampling protocols in use during the PELGAS survey, as well as the methodology to derive biomasse estimates from acoustics and fishing data., L'objectif des campagnes PELGAS est de surveiller l'écosystème pélagique du golfe de Gascogne, soumis aux pressions halieutiques et au variations climatiques, afin de fournir les éléments scientifiques nécessaires à la gestion écosystémique des ressources pélagiques du golfe. Les dynamiques spatio-temporelle des populations de petits poissons pélagiques, notamment d'anchois, sont étudiées particulièrement. La campagne a ainsi lieu au printemps, pendant la ponte des anchois, afin d'observer à la fois les œufs et les adultes. La campagne écosystémique PELGAS s'attache à récolter un maximum de paramètres à chaque niveau du réseau trophique. Des données sont collectées en continu le long de radiales parallèles couvrant l'ensemble du golfe de Gascogne, afin de caractériser au mieux les structures horizontales et verticales de l'écosystème pélagique. Des échosondeurs multifréquences et multifaisceaux renseignent en temps réel sur les patrons spatiaux et l'abondance des organismes pélagiques, du plancton jusqu'aux poissons. Simultanément, le système de pompage de surface CUFES fournit des informations complémentaires sur la ponte des petits poissons pélagiques. La présence et le nombre d'oiseaux et de mammifères marins sont enfin enregistrés en continu. Ponctuellement, les cibles acoustiques sont identifiées par pêche (chalut et pêches planctoniques) et/ou vidéo (caméra de chalut, engin remorqué EROC, profileur vidéo à plancton). Des stations bathysonde avec prélèvements bouteilles ainsi que des pêches planctoniques (WP2, Multinet) couvrant l'ensemble du golfe renseignent enfin sur le contexte hydro-planctonique. Ces mesures in-situ sont confrontées aux images satellites et aux résultats de modèles hydrodynamiques et biogéochimiques. Ce document décrit les protocoles utilisés pour collecter et analyser les données collectées lors des campagnes PELGAS.

An acoustic survey (PELGAS) is carried out every year in the Bay of Biscay in spring onboard the French research vessel Thalassa. The objective of PELGAS survey is to study the abundance and distribution of pelagic fish in the Bay of Biscay. The main target species are anchovy and sardine but they are considered in a multi-specific context and within an ecosystemic approach as they are located in the centre of pelagic ecosystem.

The initial objective of the PELGAS integrated survey was to assess the biomass of small pelagic fish in the Bay of Biscay in spring. Sampling has been extended to study the spatial structure and dynamics of the pelagic ecosystem in springtime. The PELGAS survey has produced since 2000 long-term time-series of spatially-explicit data and indices, describing the main pelagic ecosystem components: hydrology, phytoplankton, mesozooplankton, fish and megafauna. In addition to small pelagic fish biomass estimates used for fish stock assessment, the survey now delivers two types of ecosystem products: standard gridded maps of ecosystem parameters, and a time series dataset of indicators of the Bay of Biscay pelagic ecosystem state. The evolution of the PELGAS survey and sampling sampling designs are presented and discussed, to highlight their impact on the survey ecosystem products. The potential of PELGAS survey products for ecosystem assessment is demonstrated with two case studies. Series of multivariate maps are first analysed to assess the pelagic ecosystem spatial structure. A map of consistent ecosystem seascapes boundaries and of their inter-annual variability in time is presented. Second, time series of potential ecosystem indices derived from the survey are jointly analysed to select the most continuous indicators within, and across, several ecosystem components. Trends in the selected time series are interpreted to derive information on marine ecosystem status and dynamics. Challenges and future directions are discussed, with a focus on the new big data flows that could be provided by the survey in a near future.

The Pelgas16 acoustic survey has been carried out with very good weather conditions (regular low wind, medium temperatures) for the whole area, from the South of the bay of Biscay to the west of Brittany. The help of commercial vessels (two pairs of pelagic trawlers and a single one) during 18 days provided about 120 valid identification hauls instead of about 60 before 2007 when Thalassa was alone to identify echotraces. Their participation increased the precision of identification of echoes and some double hauls permitted to confirm that results provided by the two types of vessels (R/V and Fishing boats) were comparable and usable for biomass estimate purposes. These commercial vessels participated to the PELGAS survey in a very good spirit of collaboration, with the financial help of "France Filière Pêche" which is a groupment of French fishing organisations. The PELGAS16 survey observed a medium level of anchovy biomass, which seems to be a medium biomass compared to previous year's, comparable to 2010 and far away from the 2015 biomass. The biomass estimate of sardine observed during PELGAS16 is decreasing compared to the last years level of biomass. It confirms that this specie shows a variable abundance in the bay of Biscay at this period.

The Pelgas15 acoustic survey has been carried out with globally good weather conditions (regular low wind, medium temperatures) for the whole area, from the South of the bay of Biscay to the west of Brittany. The help of commercial vessels (two pairs of pelagic trawlers and a single one) during 18 days provided about 130 valid identification hauls instead of about 50 before 2007 when Thalassa was alone to identify echotraces. Their participation increased the precision of identification of echoes and some double hauls permitted to confirm that results provided by the two types of vessels (R/V and Fishing boats) were comparable and usable for biomass estimate purposes. These commercial vessels participated to the PELGAS survey in a very good spirit of collaboration, with the financial help of "France Filière Pêche" which is a groupment of French fishing organisations. The PELGAS15 survey observed the highest level of anchovy biomass never observed before (372 916 tons), pushed by a huge recruitment (the abundance of age 1 in 2015 is more or less 4 times the highest before) far from the highest level observed on the time series (186 865 tons in 2012). In the South, anchovy was mostly concentrated in the middle of the platform, and in the middle part of the bay of Biscay, anchovy appeared as very small fish with highest concentrations front of the Gironde, never observed before. In this area, anchovy was present from the coast until the shelf break continuously.

Cet atelier 2018 a été mis en place pour intercalibrer les estimations d'âge des anchois et des sardines en Atlantique entre Erwan Duhamel qui est le lecteur de ces espèces du golfe de Gascogne et Célina Chantre et Geoffrey Bled Defruit du pôle national de Sclérochronologie du laboratoire Ressources Halieutiques de Boulogne sur mer qui vont commencer à estimer l'âge de ces petits pélagiques dans le golfe de Gascogne. L'objectif est d'abord de calibrer les estimations d’âge pour ces 2 espèces de petits pélagiques dans le golfe de Gascogne et de revoir les moyens pour réaliser les images en mer lors de la campagne Pelgas et à terre en laboratoire. Cette intercalibration est basée sur la lecture d’images : 136 otolithes d'anchois et 140 otolithes de sardine par 3 lecteurs. Cet atelier a permis de calibrer les lectures entre Erwan Duhamel (lecteur d'anchois et de sardines du golfe de Gascogne) et Geoffrey Bled Defruit et Célina Chantre (lecteurs du pôle de Sclérochronologie). Les discussions ont permis d'identifier les problèmes d'estimation d'âge et de corriger les écarts entre lecteurs. En comparant les résultats des 3 lecteurs à partir des images de sardines, la précision a fortement augmentée entre la première lecture lors de l’échange et la deuxième lecture lors du workshop passant d’un pourcentage d’agrément de 71.7% à 89% et un CV de 36% à 9%. Ceci se traduit par des estimations d’âge pour la sardine réalisées par Erwan et Geoffrey sans biais dû au lecteur. En ce qui concerne l’anchois, les résultats des lectures dès la première lecture lors de l’échange ne montrent pas de différences significatives entre lecteurs avec un pourcentage d'agrément total de 83.5% et un coefficient de variation de 16.9%. Ainsi, il n’y a pas de biais entre les 3 lectures. Ce rapport d'atelier se veut être un support pour l'interprétation des otolithes de ces deux espèces.