The bathymetric DEM of the atlantic facade with a resolution of 0.001° (~ 100 m) was prepared as part of the HOMONIM project. It encompasses part of the North Sea, the Channel and the Bay of Biscay. Offshore, this DTM extends beyond the slope to approximately 4800 m depth. The DEM is designed to be used in hydrodynamic models in order to produce high-precision forecasts for coastal water levels and sea conditions and therefore improve the pertinence of the Waves-Submersion monitoring programme. This product is available with the Lowest Astronomic Tide (LAT) or the Mean Sea Level (MSL) as a vertical datum.

The anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) populations in the Bay of Biscay are jointly surveyed each year in May since 2000 and in September since 2003 by means of acoustic surveys. The integrated survey PELGAS (Doray et al., 2018) is run in May by France and covers the French shelf of the Bay of Biscay. Its objectives are to monitor the Bay of Biscay pelagic ecosystem in springtime and assess the biomass of its small pelagic fish species, including sardine and anchovy. Amongst many information on the ecosystem, the survey PELGAS provides knowledge on the adults of anchovy and sardine during their spawning in spring. The survey JUVENA (Boyra et al., 2013) is run in September by Spain. It has a larger spatial coverage than PELGAS, including part of the Spanish coast and open ocean outside the shelf because it targets juvenile anchovy. It also provides knowledge on sardine as well as other pelagic species. Both surveys are coordinated by the ICES Working Group on Acoustic and Egg Surveys for Small Pelagic Fish (WGACEGG), together with other pelagic surveys in ICES areas 7, 8 and 9. Survey protocoles are detailed in Doray et al. (2021). Briefly, fish backscatter data are recorded along the survey transect lines and pelagic trawl hauls are undertaken opportunistically to identify the echotraces to species and collect fish samples for biometric data. The trawl haul catches have provided the anchovy and sardine length data, from which the maps presented here are derived. At each trawl haul, the catch is sorted by species and weighted. A subsample by species is measured to estimate the species’ length distribution. The four maps presented here correspond to the average maps of anchovy and sardine length distributions in May and September, derived from the PELGAS and JUVENA trawl haul data series. The maps were obtained by kriging, following the procedure explained in Petitgas et al. (2011) for mapping functions instead of variables. For each species, the experimental length distribution at each haul was fitted by a linear combination of Legendre polynomials, the coefficients of which were co-kriged. The number of polynomials varied from 15 to 22 depending on the survey and species, with a higher number for sardine and in autumn. The length histogram at each grid node was then deduced from the mapped coefficients. When the length distribution at a given haul was estimated with less than 40 individual fish, the haul was not taken into account for mapping. This threshold defined presence and absence of the species in the haul data sets. The trawl hauls from 2000 to 2019 were pooled for the PELGAS series (1965 stations) and from 2003 to 2020 for JUVENA (852 stations). The mapping was performed on the same grid for both PELGAS and JUVENA and both species, and with similar moving kriging neighbourhoods. The grid has a mesh size of 0.25 x 0.25 decimal degree square. In addition to mapping the length distribution, presence/absence was mapped for each species by ordinary kriging on the same grid and with the same neighbourhoods as previously. The computations were performed in R (version 4.0.5) with the RGeostats package (version 13.0.1) freely available at http://rgeostats.free.fr. The map data files comprise for each species the following information: the geographical coordinates of the grid points, the probability of presence and the probability of each length class of width 0.5 cm ranging from 2.5 to 27 cm.

The Pélagiques Gascogne (PELGAS, Doray et al., 2000) integrated survey aims at assessing the biomass of small pelagic fish and monitoring and studying the dynamics and diversity of the Bay of Biscay pelagic ecosystem in springtime. PELGAS has been conducted within the EU Common Fisheries Policy Data Collection Framework and Ifremer’s Fisheries Information System. The PELGAS survey model has allowed for the establishment of a long-term time-series of spatially-explicit data of the Bay of Biscay pelagic ecosystem since the year 2000. Main sampled components of the targeted ecosystem are: hydrology, phytoplankton, mesozooplankton, fish and megafauna (cetacean and seabirds). This dataset presents gridded maps of standard pelagic ecosystem parameters collected in the main sampled components during the PELGAS survey. Ecosystem parameters were mapped on a 15km x 15km grid by applying a block averaging procedure (Petitgas et al., 2009, 2014). The dataset also includes the ecologically meaningful survey dates proposed by Huret et al. (2017), mapped on the same grid. Details on survey protocols and data processing methodologies can be found in Doray et al., (2014, 2017a). This dataset was used in Authier et al., 2017; Doray et al., 2017b, 2017c, 2017a; Huret et al., 2017; Petitgas et al., 2017.

This dataset comprises stomach contents of small pelagic fish species on the french shelf of the Bay of Bisacy, in spring, autumn and winter, from 2004 to 2024. The spring data were acquired in May on the pelagic survey series PELGAS from 2004 to 2024, the autumn data in October/Novermber on the demersal survey series EVHOE from 2020 to 2024 and the winter data were acquired on chartered fishing vessels in February 2023 and 2024. The dataset concerns anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) in the 3 seasons and also mackerel (Scomber scombrus), sprat (Sprattus, sprattus) and horse mackerel (Trachurus trachurus) in spring for some years. The dataset represents a unique long-term monitoring of stomach contents characterized with a low taxonomic resolution and semi-quantitative abundance quotation.  The pelagic ecosystem survey PELGAS (Doray et al., 2018) is run in each year in May since 2000, to monitor the Bay of Biscay pelagic ecosystem at springtime and assess the biomass of its small pelagic fish species. During the survey, pelagic trawl hauls are undertaken to identify echotraces to species and to measure individual fish traits. All hauls are performed during day time. In 2010, some hauls were undertaken at night to sample stomach contents over the day/night cycle. The fish stomachs are sampled from the haul catch. For a given species, twenty individuals are selected at random from the catch, their stomachs dissected and preserved. This is repeated at three hauls in each of the ten spatial strata defined to cover the entire Biscay shelf. In some years, fish length categories (lower and greater than 14 cm for anchovy and 18 cm for sardine) were also considered when sampling the stomachs. Stomach sampling by species depended on the trawl haul catch and all species were not systematically sampled jointly at the same trawl haul. Also, the number of stations with stomach sampling varied between species and years. The stomachs were preserved in formaline until 2018 and in ethanol since. Anchovy and sardine stomach sampling on the demersal survey EVHOE (Mahe and Poulard, 2005) followed the same protocole as for PELGAS but with fewer stations, depending on the catch of anchovy and sardine in the bottom trawl. In 2020 due to the Covid pandemic, the PELGAS survey was canceled and to compensate, a pair-trawler was chartered in autumn to perform some pelagic trawl hauls during the EVHOE 2020 survey. In winter 2023 and 2024 a pair-trawler was also chartered, for identifying echotraces observed previously on the survey DRIX (Doray et al., 2024) in the area delimited by the Gironde and Loire estuaries, the coast and the 100 m isobath. On the fishing vessels the fish were frozen onboard, the stomachs were dissected on land in the laboratory and preserved in ethanol.  The taxonomic analysis of the stomach contents was performed in the laboratory under a binocular magnifyer by the company LAPHY. A simplified taxonomic resolution was used, which considered five ichtyoplankton groups, two copepod groups, euphausids or mysids, amphipods, two decapod groups, other crustacea, other zooplankton, phytoplankton and pulp. Taxon abundance was defined by a quotation : 0 (absence), 1 (presence : <10 individuals), 2 (abundant : between 10 and 100), 3 (very abundant : > 100). The dataset comprises trawl haul information, information on the quality of the stomach contents and abundance quotes for the list of plankton taxons. A preliminary analysis of the data (Petitgas, 2024) showed a large overlap in stomach contents between species, the importance of small copepods in the diets, and how different drivers such as habitat and length influence the diets. 

The Pélagiques Gascogne (PELGAS, Doray et al., 2000) integrated survey aims at assessing the biomass of small pelagic fish and monitoring and studying the dynamics and diversity of the Bay of Biscay pelagic ecosystem in springtime. PELGAS has been conducted within the EU Common Fisheries Policy Data Collection Framework and Ifremer’s Fisheries Information System. Details on survey protocols and data processing methodologies can be found in Doray et al., (2014, 2018). This dataset comprises the abundance (no. of individuals), biomass (metric tons), mean length (cm), mean weight (g) of marine organisms collected by midwater trawling to identify fish echoes detected during PELGAS surveys (2000-2018). All parameters have been raised to the trawl haul level. Trawl haul metadata and species reference list are also provided.

A consistent dataset of bottom trawl survey data spanning 47 years in the Bay of Biscay was assembled. The dataset includes data from the current EVHOE survey from 1987 to 2019 and two previous surveys carried out in 1973 and 1976. The recent EVHOE time-series from 1997 is also available from DATRAS (https://www.ices.dk/data/data-portals/Pages/DATRAS.aspx). The catch in numbers and weight (kg) per haul of all Rajiformes species caught in these surveys is provided. Haul information is provided for all hauls, including those with no catch of Rajiformes. Areas of the sampling strata of the survey and spatial polygones of these strata are provided in separate files.

These data are outputs of a spatio-temporal model inferring fish distribution. The maps are based on high-resolution catch data (VMS-logbook). They have a montly time resolution and a 0.05° spatial resolution. Four demersal species of the Bay of Biscay are available in the dataset: common sole (Solea solea), megrim (Lepidorhombus whiffiagonis), anglerfish (Lophius spp) and thornback ray (Raja clavata). Maps are provided for year 2008 to 2018 ; they were produced in the context of the MACCO project (https://www.macco.fr/en/accueil-english/), an Ifremer project that aims at proposing alternative management strategies for the mixed demersal fisheries of the Bay of Biscay.

In October 2019 we chose 15 sites from the 2019 EVHOE survey for environmental DNA (eDNA) sampling. The French international EVHOE bottom trawl survey is carried out annually during autumn in the BoB to monitor demersal fish resources. At each site, we sampled seawater using Niskin bottles deployed with a circular rosette. There were nine bottles on the rosette, each of them able to hold ∼5 l of water. At each site, we first cleaned the circular rosette and bottles with freshwater, then lowered the rosette (with bottles open) to 5 m above the sea bottom, and finally closed the bottles remotely from the boat. The 45 l of sampled water was transferred to four disposable and sterilized plastic bags of 11.25 l each to perform the filtration on-board in a laboratory dedicated to the processing of eDNA samples. To speed up the filtration process, we used two identical filtration devices, each composed of an Athena® peristaltic pump (Proactive Environmental Products LLC, Bradenton, Florida, USA; nominal flow of 1.0 l min–1 ), a VigiDNA 0.20 μm filtration capsule (SPYGEN, le Bourget du Lac, France), and disposable sterile tubing. Each filtration device filtered the water contained in two plastic bags (22.5 l), which represent two replicates per sampling site. We followed a rigorous protocol to avoid contamination during fieldwork, using disposable gloves and single-use filtration equipment and plastic bags to process each water sample. At the end of each filtration, we emptied the water inside the capsule that we replaced by 80 ml of CL1 conservation buffer and stored the samples at room temperature following the specifications of the manufacturer (SPYGEN, Le Bourget du Lac, France). We processed the eDNA capsules at SPYGEN, following the protocol proposed by Polanco-Fernández et al., (2020). Half of the extracted DNA was processed by Sinsoma using newly developped ddPCR assays for European seabass (Dicentrachus labrax), European hake (Merluccius merluccius) and blackspot seabream (Pagellus bogaraveo).  The other half of the extracted DNA was analysed using metabarcoding with teleo primer. The raw metabarcoding data set is available at https://www.doi.org/10.16904/envidat.442 Bottom trawling using a GOV trawl was carried out before or after water sampling. The catch was sorted by species and catches in numbers and weight were recorded. No blackspot seabream individuals were caught.   Data content: * ddPCR/: contains the ddPCR counts and DNA concentrations for each sample and species. * SampleInfo/: contains the filter volume for each eDNA sample. * StationInfo/: contains metadata related to the data collected in the field for each filter. * Metabarcoding/: contains metabarcoding results for teleoprimer. * Trawldata/: contains catch data in numbers and weight (kg).      

The data sets presented here result from the long-term monitoring of individual growth patterns in anchovy and sardine in the Bay of Biscay, from 2000 to 2018. They derived from the PELGAS survey series (Doray et al., 2018), which monitors annually the Bay of Biscay pelagic ecosystem since 2000. The survey is performed in May during the peak spawning of anchovy and main spawning of sardine. Among the many data collected, anchovy and sardine populations are assessed by combining acoustic records with pelagic trawl hauls catches and ICES survey protocoles are used, as detailed in Doray et al. (2021). Briefly, fish acoustic backscatter are recorded along survey transect lines and pelagic trawl hauls undertaken opportunistically to identify echotraces to species and collect fish samples for acquiring biometric data. At each trawl haul and for each species, a random subsample of individuals is taken to establish the species’ length distributions. For anchovy and sardine, this subsample is further subsampled, spanning the whole length range, to take individual fish measurements. These amount to extracting otoliths and measuring individuals’ age, length, weight, sexual maturity and other parameters. Individual measurements are taken on fourty individuals of anchovy and sardine when the species are present in the catch. For each individual fish, the two otolith sagittae are extracted on board, mounted in leukit for age reading on board when permitting and/or on land in the laboratory. Growth patterns in the otoliths were analysed on land with a binocular stereomicroscope under reflected natural light. For anchovy, otoliths’ growth was measured for all individuals in all the hauls. For sardine, trawl hauls were selected and all individual otoliths were measured in each selected haul. The selection was made using the geographical stratification defined in Petitgas et al. (2018) based on the ecosystem spatial structure. An average of two to three hauls in each of the four strata were selected per year. The otoliths mounted in leukit were imaged and growth-at-age in the otoliths was measured with the software TNPC (Traitement numérique des pièces calcifiées: Mahé et al., 2009). Under the binocular microscope and natural light, the otoliths showed hyaline (aragonite-poor) rings corresponding to winter periods of low growth and between the rings, white opaque (aragonite-rich) portions corresponding to annual growth periods. The annual ring determination, the age assignment and the measurement of annual ring diameters followed ICES protocoles and guidelines for anchovy and sardine (ICES, 2010; 2011). The age was estimated as the number of hyaline rings. If the edge was hyaline, it was counted as a ring as a hyaline edge observed within the first half of the year is assumed to represent the last winter. The diameter of each annual ring was measured from middle of the hyaline ring on one side to the middle of the ring on the opposite side along the major elongated axis of the otolith and passing through its centre. The distance was expressed in mm after calibration of the stereomiscroscope and the pixel images. Such diameter corresponded to growth-at-age. Ages 0 to 4 were considered (diameters R1 to R5). The total diameter of the otolith was also measured. The data sets span 19 years, from 2000 to 2018 and comprise 20,186 and 8,624 individual fish analyzed at 535 and 235 trawl hauls for anchovy and sardine, respectively. These data sets were used by Boëns et al. (2021 and 2023) to analyse changes in growth patterns and growth-selective mortality at age in anchovy and sardine under environmental and fishing pressures. References: Doray, M., Boyra, G. and Van Der Kooij, J. (eds) (2021). ICES Survey Protocols – Manual for acoustic surveys coordinated under ICES Working Group on Acoustic and Egg Surveys for Small Pelagic Fish (WGACEGG). 1st Edition. ICES Techniques in Marine Environmental Sciences, 64. https://doi.org/10.17895/ices.pub.7462  Doray, M., Petitgas, P., Romagnan, J.-B., Huret, M., Duhamel, E., Dupuy, Ch., Spitz, J., Authier, M., Sanchez, F., Berger, L., Doremus, G., Bourriau, P., Grellier, P. and Masse, J. (2018). The PELGAS survey: ship-based integrated monitoring of the Bay of Biscay pelagic ecosystem. Progress In Oceanography, 166, 15-29. https://doi.org/10.1016/j.pocean.2017.09.015 ICES (2010). Report of the Workshop on Age reading of European anchovy (WKARA), 9-13 November 2009, Sicily, Italy. ICES CM 2009/ACOM: 43. 122 pp. https://doi.org/10.17895/ices.pub.19280525 ICES (2011). Report of the Workshop on Age Reading of European Atlantic Sardine (WKARAS), 14-18 February 2011, Lisbon, Portugal. ICES CM 2011/ACOM:42. 91 pp. https://doi.org/10.17895/ices.pub.19280855 Petitgas, P., Huret, M., Dupuy, Ch., Spitz, J., Authier, M., Romagnan, J.-B. and Doray, M. (2018). Ecosystem spatial structure revealed by integrated survey data. Progress In Oceanography, 166, 189-198. https://doi.org/10.1016/j.pocean.2017.09.012 Mahe, K., Bellail, R., Dufour, J.-L., Boiron-Leroy, A., Dimeet, J., Duhamel, E., Elleboode, R., Felix, J., Grellier, P., Huet, J., Labastie, J., Le Roy, D., Lizaud, O., Manten, M.-L., Martin, S., Metral, L., Nedelec, D., Verin, Y. and Badts, V. (2009). Synthèse française des procédures d'estimation d'âge / French summary of age estimation procedures. https://archimer.ifremer.fr/doc/00000/7294/ Boëns, A., Grellier, P., Lebigre, Ch. and Petitgas, P. (2021). Determinants of growth and selective mortality in anchovy and sardine in the Bay of Biscay. Fisheries Research, 239, 105947. https://doi.org/10.1016/j.fishres.2021.105947 Boëns, A., Ernande, B., Petitgas, P. and Lebigre, Ch. (2023). Different mechanisms underpin the decline in growth of anchovies and sardines of the Bay of Biscay. Evolutionary Applications, 16: 1393–1411. https://doi.org/10.1111/eva.13564  

The Coriolis Ocean Dataset for Reanalysis for the Ireland-Biscay-Iberia region (hereafter CORA-IBI) product is a regional dataset of in situ temperature and salinity measurements. The latest version of the product covers the period 1950-2014. The CORA-IBI observations comes from many different sources collected by Coriolis data centre in collaboration with the In Situ Thematic Centre of the Copernicus Marine Service (CMEMS INSTAC).  The observations integrated in the CORA-IBI product have been acquired both by autonomous platforms (Argo profilers, fixed moorings, gliders, drifters, sea mammals, fishery observing system from the RECOPESCA program), research or opportunity vessels ( CTDs, XBTs, ferrybox).  This CORA-IBI product has been controlled using an objective analysis (statistical tests) method and a visual quality control (QC). This QC procedure has been developed with the main objective to improve the quality of the dataset to the level required by the climate application and the physical ocean re-analysis activities. It provides T and S individual profiles on their original level with QC flags. The reference level of measurements is immersion (in meters) or pressure (in decibars). It is a subset on the IBI (Iberia-Bay-of-Biscay Ireland) of the CMEMS product referenced hereafter. The main new features of this regional product compared with previous global CORA products are the incorporation of coastal profiles from fishery observing system (RECOPESCA programme) in the Bay of Biscay and the English Channel as well as the use of an historical dataset collected by the Service hydrographique de la Marine (SHOM).