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L’Unité de recherche HMMN, créée en 2005, appartient depuis 2011 au Département Ressources Biologiques et Environnement (RBE), qui est l’un des 4 Département scientifiques de l’IFREMER, avec les Départements Océanographie et Dynamique des Ecosystèmes (ODE), Recherches physiques et Ecosystèmes de fond de Mer (REM) et Infrastructures de Recherche et Systèmes d’Information (IRSI). L’Unité de recherche HMMN est constituée de deux laboratoires, l’un situé à Boulogne sur mer dans les Hauts de France (LRHBL) et l’autre à Port-en-Bessin en Normandie (LRHPB). Ces deux laboratoires, ainsi que les autres laboratoires des Départements ODE et REM localisés à Boulogne s/mer et Port-en-Bessin (ODE: deux Laboratoires Environnement Ressources, LERBL et LERN; REM: un Laboratoire Comportement des Structures en Mer, LCSM), sont rattachés administrativement au Centre de Manche – Mer du Nord (CMMN) de l’IFREMER. L’équipe HMMN effectue des recherches en écologie marine et halieutique, principalement centrées sur les écosystèmes de Manche et Sud mer du Nord. Ces recherches trouvent un prolongement dans l’appui aux politiques publiques concernant la conservation des écosystèmes marins et l’aménagement des pêcheries et d’autres usages du domaines maritime (e.g., extraction de sables et granulats marins, production d’énergies marines renouvelables), dans un contexte de changement climatique. L’unité HMMN contribue à la collecte de données halieutiques et écosystémiques en mer, par enquêtes, et en laboratoire, et centralise à travers la cellule CREDO, le traitement et l’envoi des données halieutiques requises par une variété d’organismes scientifiques, gestionnaires, professionnels et non gouvernementaux. HMMN coordonne trois campagnes en mer à grande échelle régionale et héberge trois infrastructures technologiques: un Pôle National de Sclérochronologie (PNS), une Plateforme Réseaux Trophiques (PRT), et un Pôle de Taxinomie et d’Ecologie du Zooplancton (PTEZOO). En cherchant à mieux comprendre les interactions entre les ressources halieutiques et leur environnement (biotique et abiotique), dans un contexte de changement global, l’unité HMMN contribue spécifiquement à plusieurs des enjeux définis dans le projet de l’institut: E6 (Évaluer le devenir des écosystèmes côtiers dans le changement global), E9 (Identifier les effets des interactions entre groupes fonctionnels sur la dynamique des écosystèmes exploités), E10 (Évaluer la résilience et anticiper les changements d’état – points de basculement des socio-écosystèmes et de la biodiversité associée aux différents niveaux d’organisation), et E13 (Identifier de nouvelles bioressources marines). Ces enjeux sont déclinés au sein de l’Unité dans trois Thèmes scientifiques correspondant à des niveaux d’organisation systémique de plus en plus complexes : Individus, Populations et Niches Ecologiques (Thème 1); Communautés, Réseaux Trophiques et Biodiversité (Thème 2); Flottilles, Exploitation et Scénarios de Gestion (Thème 3). Les approches méthodologiques menées en 2021 pour améliorer notre compréhension des processus ont utilisé et/ou combiné des analyses empiriques de données d’observation in-situ, expérimentales et de modélisation, ces dernières étant directement liées à deux défis du projet d’Institut : D2 (l’expérimentation pour améliorer notre compréhension des processus) et D3 (la modélisation prédictive intégrée des socio-écosystèmes). Enfin, l’unité HMMN a joué en 2021, comme au cours des années précédentes, un rôle de catalyseur pour les sciences marines au niveau régional d’une part dans les Hauts-de-France comme membre actif de la Fédération de Recherche Campus de la Mer, l’un des chefs de file de projets CPERs et enfin comme unité participant à l’École universitaire de recherche transdisciplinaire pour les sciences marines, l’halieutique et les produits de la mer (Transdisciplinary graduate school for marIne, Fisheries and SEAfood sciences, IFSEA) mis en place en 2021 dans le cadre des PIA4 de l’Agence Nationale de la Recherche (ANR) et d’autre part en Normandie comme membre de la Fédération de Recherche Merlin. De plus, l’unité HMMN a continué à renforcer son implication dans les régions ultrapériphériques (RUP), avec plusieurs projets comme Accobiom ciblant la Guadeloupe, la Martinique, la Guyane et la Réunion mais aussi à travers de nombreux travaux et expertises menés à Saint-Pierre et Miquelon. Enfin, au niveau international, l’unité HMMN contribue aussi au rayonnement de l’IFREMER au travers de recrutements (chercheurs, post-doctorants, étudiants en thèse) et de l’implication à haut niveau de chercheurs HMMN dans des projets de recherche européens et de groupes de travail structurants (e.g., présidence de GTs du CIEM, du CSTEP, de RCGs, experts nommés pour le GIEC ou l’IPBES). En 2021, de nouveaux projets structurants pour l’unité HMMN ont été acceptés (e.g, CPER IDEAL, FORESEA 2050, MAESTRO, SAR, CARPARC, IPREM, ACCOBIOM). Une thèse a été soutenue 2021 avec succés et deux nouvelles thèses ont démarré. L’équipe a également maintenu son niveau d’engagement dans l’APP, qu’il s’agisse d’avis et expertises (nécessitant dans le cadre de certains Groupes de Travail internationaux des visioconférences de plus d’une réunion en présentiel), ou de réalisation de campagnes à la mer (IBTS, CGFS, COMOR, DCSMM, IGA).

This annual report on ecological and fishery monitoring (n ° 37) of the Elecrique Nuclear Production Center (CNPE) in Flamanville (Manche department) concerns the year 2020. This monitoring, which started in 1983, relates to the benthic, fishery and pelagic compartments. It aims to study the medium and long-term temporal evolution of the different marine domains (pelagos, benthos and fishery) and their parameters associated with a local spatial scale (near CNPE and its area of influence). The year 2020 is the 35th year of operation of the CNPE in Flamanville (entry into operation of the CNPE 1986)., Ce rapport annuel de la surveillance écologique et halieutique (n°37) du Centre Nucléaire de production Électrique de Flamanville (département de la Manche) concerne l'année 2020. Cette surveillance, qui a débuté en 1983, porte sur les compartiments benthique, halieutique et pélagique. Elle vise à étudier l’évolution temporelle à moyen et long terme des différents domaines marins (pelagos, benthos et halieutique) et de leurs paramètres associés à une échelle spatiale locale (proche des centrales et de sa zone d’influence). L'année 2020 est la 35ème année de fonctionnement du CNPE de Flamanville (mise en fonctionnement du CNPE 1986).

This annual report on ecological and fishery monitoring (n °34) of the Electrique Nuclear Production Center (CNPE) in Penly (Seine-Maritime department) concerns the year 2020. This monitoring, which started in 1987, relates to the pelagic and fishery compartments. It aims to study the medium and long-term temporal evolution of the different marine domains (pelagos and fishery) and their parameters associated with a local spatial scale (near CNPE and its area of influence). The year 2020 is the 31th year of operation of the CNPE in Penly (entry into operation of the CNPE 1989)., Ce rapport annuel de la surveillance écologique et halieutique (n°34) du Centre Nucléaire de Production d'Électricité de Penly (département de Seine Maritime) concerne l'année 2020. Cette surveillance, qui a débuté en 1987, porte sur les compartiments pélagique (physico-chimie, microbiologie, phytoplancton, zooplancton) et halieutique. Elle vise à étudier l’évolution temporelle à moyen et long terme des différents domaines marins (pelagos, halieutique) et de leurs paramètres associés à une échelle spatiale locale (proche de la centrale et de sa zone d’influence). L'année 2020 est la 31e année de fonctionnement du CNPE de Penly (mise en fonctionnement du CNPE 1989).

Ce travail constitue le 42ème rapport de surveillance du site électronucléaire de Gravelines dont la grande puissance énergétique est assurée par le fonctionnement de 6 tranches. Ce site, implanté sur le littoral, présente une prise d’eau de mer assurant le refroidissement du système et un rejet côtier d’eau chaude en surface. Le fonctionnement de la centrale a débuté en 1980 et elle a atteint la puissance maximale en 1986. La surveillance concerne les domaines pélagique (hydrologie, microbiologie, phytoplancton, zooplancton), halieutique (larves et œufs de sole, de sprat et crevettes grises), et benthique (intertidal et subtidal). La stratégie de surveillance est basée sur une approche spatiale et temporelle (i) Étude de l’impact immédiat par comparaison de la station « Prise d’eau » et de la station « Canal de rejet » sur une surface limitée (ii) Étude de l’évolution à moyen ou à long terme du milieu marin par rapport à une situation de référence (échelle locale).

This annual report on ecological and fishery monitoring (n °33) of the Elecrique Nuclear Production Center (CNPE) in Penly (Seine-Maritime department) concerns the year 2019. This monitoring, which started in 1987, relates to the pelagic and fishery compartments. It aims to study the medium and long-term temporal evolution of the different marine domains (pelagos and fishery) and their parameters associated with a local spatial scale (near CNPE and its area of influence). The year 2019 is the 30th year of operation of the CNPE in Penly (entry into operation of the CNPE 1989)., Ce rapport annuel de la surveillance écologique et halieutique (n°33) du Centre Nucléaire de production Électrique de Penly (département de Seine Maritime) concerne l'année 2019. Cette surveillance, qui a débuté en 1987, porte sur les compartiments Pélagique (Physico-chimie, microbiologie, phytoplancton, zooplancton) et halieutique. Elle vise à étudier l’évolution temporelle à moyen et long terme des différents domaines marins (pelagos, halieutique) et de leurs paramètres associés à une échelle spatiale locale (proche des centrales et de sa zone d’influence). L'année 2019 est la 30e année de fonctionnement du CNPE de Penly (mise en fonctionnement du CNPE 1989).

This annual report on ecological and fishery monitoring (n ° 36) of the Elecrique Nuclear Production Center (CNPE) in Flamanville (Manche department) concerns the year 2019. This monitoring, which started in 1983, relates to the benthic, fishery and pelagic compartments. It aims to study the medium and long-term temporal evolution of the different marine domains (pelagos, benthos and fishery) and their parameters associated with a local spatial scale (near CNPE and its area of influence). The year 2019 is the 34th year of operation of the CNPE in Flamanville (entry into operation of the CNPE 1986)., Ce rapport annuel de la surveillance écologique et halieutique (n°36) du Centre Nucléaire de production Électrique de Flamanville (département de la Manche) concerne l'année 2019. Cette surveillance, qui a débuté en 1983, porte sur les compartiments benthique, halieutique et pélagique. Elle vise à étudier l’évolution temporelle à moyen et long terme des différents domaines marins (pelagos, benthos et halieutique) et de leurs paramètres associés à une échelle spatiale locale (proche des centrales et de sa zone d’influence). L'année 2019 est la 34ème année de fonctionnement du CNPE de Flamanville (mise en fonctionnement du CNPE 1986).

The objectives of the Working group on Surveys on Ichthyoplankton in the North Sea and adjacent Seas (WGSINS) were to review Ichthyoplankton surveys undertaken for assessment purposes, coordinate the surveys in 2020, prepare data for archiving, provide quality assurance on species identification and identify additional objectives that can be achieved within the existing survey designs. The international herring larvae surveys in the North Sea (IHLS) were in autumn 2018 and early 2019 affected by severe technical problems of one of the research vessels. As a consequence, spatial information on larvae abundance around the Orkney/Shetlands and in the English Channel was too limited to be included in the herring assessment 2019. Only abundance data of the Buchan and Banks components were used. The MIK net (Midwater Ring Net) sampling during the first quarter international bottom trawl survey in 2019 (Q1 IBTS) reported foraging herring larvae in higher quantities in the western part of the North Sea, the Southern Bight and in the Skagerrak. In the eastern part of the North Sea, the potential nurseries, abundance of larger larvae was very low, and virtually no larvae occurred in the German Bight. Simulations on sampling effort reduction showed the MIK index to be relatively stable, even when sampling is reduced by 50%, but such a reduction could be disadvantageous for representative sampling of less abundant species. As an addition to the conventional MIK sampling, a sampling programme on herring larvae recruiting from the Downs stock component has been carried out during 2018 and 2019. The Downs recruitment survey (DRS) revealed larger quantities of foraging larvae, which are so far not integrated in the recruitment index of North Sea autumn spawning herring. The Rügen herring larvae survey (RHLS) considers the major spawning areas of western Baltic spring spawning herring. There is no substantial herring recruitment in the area. Several studies tried to utilize surveys to gather additional information. The Northern Irish MIK survey (NIMIK) usually provides recruitment information on gadoids, but also collect information on the wider ecosystem. As one example, a two decade long time-series of gelatinous zooplankton abundance and distribution in the Irish Sea has been built on survey catches. A pilot study tried to use samples from the Q3 IBTS to establish a sprat recruitment index. Results from 2018 and 2019 indicate very promising potential, but wider area coverage would be beneficial. Thus participating countries are welcome to contribute to the ongoing study. Analyses of three years of litter sampling during MIK surveys revealed sources of litter in the water column, and uses the MIK net flowmeters to quantify the amount. The samples may also provide insights into possible pathways of drifted material. While progressing with the original survey objectives, WGSINS will continue to invest efforts in using herring larval surveys to provide additional information. WGSINS will summarize information on co-occurring fish larvae, and establish time-series to form the basis for further analyses of species distribution, abundance and, if possible, trends in recruitment.

The ICES herring assessment working group (HAWG) met on an interactive virtual platform for eight days in March 2020 to assess the state of five herring stocks and three sprat stocks. HAWG also provided advice for four sandeel stocks but reported on those prior to this meeting in February. The working group conducted update assessments for the five herring stocks. An analytical assessment was performed for the combined North Sea and Division 3.a sprat, and a data limited assessment (ICES category 3) was conducted for English Channel sprat (spr.27.7de). The North Sea autumn spawning herring (her.27.3a47d) SSB in 2019 was estimated at 1.7 mill tonnes while F2–6 in 2019 was estimated at 0.18, which is below FMSY. Recruitment in 2019 is comparable to the 2018 value and remains within the low recruitment regime observed since 2015. Year classes since 2002 are estimated to be consistently weak with year classes 2014 and 2016 some of the weakest on record. ICES considers that the stock is still in a low productivity phase.The Western Baltic spring-spawning herring (her.27.20-24) assessment was updated. The SSB and recruitment in 2019 are record low. SSB is estimated to be around 56 600 tonnes which is below both Bpa and Blim. Recruitment has been low since 2006 and it has been further deteriorating with time. Fishing mortality has decrease in 2019 to 0.382 but is still well above FMSY (0.31). The stock has decreased consistently during the second half of the 2000s and given the continued low recruitments the stock is not able to recover above Blim unless a drastic reduction in fishing effort is applied.The Celtic Sea autumn and winter spawning stock (her.27.irls) is estimated to be at a very low level. SSB is currently estimated to be at the lowest level in the time-series and has been below Blim (34 000 t) since 2016. Mean F(2–5 rings) was estimated at 0.49 in 2019, having decreased from the peak of 1.15 in 2017. Recruitment has been consistently below average from 2013-2018. Recruitment in 2019 is estimated to be above average. The assessment of the combined stocks of herring in 6.aN and 6.aS/7.b, c (her.27.6a7bc) went through an interbenchmark procedure in 2019 and the advice is based on trends from an analytical assessment. SSB and recruitment have been declining since around 2000 and are currently at the lowest level in the time-series. Fishing mortality has reduced since 2016 when catches have been limited to a scientific monitoring TAC but recovery of the stock is hampered by the very low recruitment.Irish Sea autumn spawning herring (her.27.nirs) assessment shows a stable SSB in 2019 compared to previous years at around 24 700 tonnes. The stock has experienced large incoming year classes in recent years. Fishing mortality (F4–6) is estimated at 0.18, one of the lowest in the timeseries and below FMSY (0.266). Catches have been relatively stable since the 1980s, and close to the TAC in recent years. North Sea and 3.a Sprat (spr.27.3a4) were combined into a single assessment unit during the 2018 benchmark. Perception of the status of the stock is dominated by the dynamics in Subarea 4 where most of the catches occur. Despite the fact that fishing mortality in the last years has fluctuated at high levels between 0.6–2.2, recruitments slightly but consistently above the average during recent years have contributed to an increase in SSB well above MSY Bescapement. The estimates for 2020 show an SSB of 266 000 t which is more than double of Bpa (125 000 t).Catch advice for sprat in the English Channel (7.d, e) (spr.27.7de) was based on criteria for an ICES category 3-based method. Data available are landings and a short time-series of acoustic biomass (2013–2019). The acoustic biomass has fluctuated over time and the 2019 biomass has increased from the 2018 estimate. The HAWG reviewed the assessments performed on four sandeel stocks and the related advice of these stocks. Section 9 of this report contains the assessments of sandeel in Division 3.a and Subarea 4. Standard issues such as the quality and availability of data, estimating the amounts of discarded fish, availability of data through industry surveys and scientific advances particularly with respect to stock discrimination relevant to small pelagic fish were discussed. All data and scripts used to perform the assessments and the forecast calculations are available at https://github.com/ICES-dk/wg_HAWG and accessible to anyone.

Ce travail constitue le 41ème rapport de surveillance du site électronucléaire de Gravelines dont la grande puissance énergétique est assurée par le fonctionnement de 6 tranches. Ce site, implanté sur le littoral, présente une prise d’eau de mer assurant le refroidissement du système et un rejet côtier d’eau chaude en surface. Le fonctionnement de la centrale a débuté en 1980 et elle a atteint la puissance maximale en 1986. La surveillance concerne les domaines pélagique (hydrologie, microbiologie, phytoplancton, zooplancton), halieutique (larves et œufs de sole, de sprat et crevettes grises), et benthique (intertidal et subtidal). La stratégie de surveillance est basée sur une approche spatiale et temporelle (i) Étude de l’impact immédiat par comparaison de la station « Prise d’eau » et de la station « Canal de rejet » sur une surface limitée (ii) Étude de l’évolution à moyen ou à long terme du milieu marin par rapport à une situation de référence (échelle locale).

Condition indices aim to evaluate the physiological status of fish larvae by estimating both the level of starvation and potential of survival. Histological indices reveal direct effects of starvation whereas biochemical indices such as lipid classes or RNA:DNA ratios are used as proxies of condition, giving information on the amount of energy reserves and growth rate, respectively. We combined these three indices to evaluate ontogenetic variations of growth performance, lipid dynamics and nutritional condition of plaice larvae caught in the field during winter 2017 in the eastern English Channel and the Southern Bight of the North Sea. RNA:DNA ratios showed that larvae at the beginning of metamorphosis (stage 4) had a lower growth rate than younger individuals (stages 2 and 3). A significant increase in the proportion of triglycerides also occurred at stage 4, indicating energy storage. Histological indices indicated that most of the larvae were in good condition, even younger ones with low lipid reserves. There was, however, an increase in the proportion of healthy individuals over ontogeny, especially with respect to liver vacuoles which were larger and more numerous for stage 4 larvae. Combined together, these condition indices revealed the ontogenetic shift in the energy allocation strategy of plaice larvae. Young larvae (stages 2 and 3) primarily allocate energy towards somatic growth. The decrease in growth performance for stage 4 was not related to poor condition, but linked to a higher proportion of energy stored as lipids. Since the quantity of lipid reserves is particularly important for plaice larvae to withstand starvation during metamorphosis, this could be considered as a second critical period after the one of exogenous feeding for larval survival and recruitment success.

Monitoring n° 30 of PENLY nuclear power - plant takes into account studies between March and September 2017. Hydrology, microbiology, phytoplankton, zooplankton and fishing are studied. This power-plant has been in operation for twenty-eight years., La surveillance n° 30 sur le site de PENLY couvre la période de mars à septembre 2017. Les domaines étudiés sont l'hydrologie, la microbiologie, le plancton végétal et animal et le domaine halieutique. L’année 2017 est la vingt huitième année de fonctionnement de la centrale.

The ICES herring assessment working group (HAWG) met for seven days in March 2018 to assess the state of five herring stocks and four sprat stocks. HAWG also provided advice for seven sandeel stocks but reported on those prior to this meeting. The working group conducted update assessments for five of the herring stocks. An analytical assessment was performed for North Sea sprat, and data limited assessments (ICES category 3 and 5) were conducted for English Channel sprat and Division 3.a sprat. The assessment of sprat in the Celtic Sea (spr.27.67a–cf–k) was not updated this year.The North Sea autumn spawning herring (her.27.3a47d) SSB in 2017 was estimated at 1.9 mill tonnes while F2–6 in 2017 was estimated at 0.21, which is below the management plan target F2–6 and below FMSY. Fishing mortality on juveniles, mean F0–1 is 0.032, below the agreed ceiling. Recruitment in 2017 is estimated to be very low. The estimate of 0-wr fish in 2017 (2016 year class) is estimated to be at approximately 18 billion, which is very low even compared to other recent low recruitments. Year classes since 2002 are estimated to be consistently weak with year classes 2015 to 2017 some of the weakest on record. ICES considers that the stock is still in a low productivity phase.The Western Baltic spring spawning herring (her.27.20-24) assessment was updated. The SSB in 2017 was relatively stable compared to recent years and is estimated to be around 104 000 tonnes. Fishing mortality has been estimated at 0.33 which is is above the estimate of FMSY (0.31). Recruitment has been low since 2006 and 2017 is the lowest observed in the time-series. Under a historical perspective the estimate of SSB of 104 170 tonnes in 2017 is considered low, below both Bpa and Blim, The stock has decreased consistently during the second half of the 2000s and given the continued low recruitments the stock seems not to be able to recover to these higher biomass levels.The Celtic Sea autumn and winter spawning stock (her.27.irls) is estimated to be at a low level, declining from a recent high biomass that peaked in 2011. SSB is currently estimated at 36 000 tonnes in 2017, coming down from 136 000 tonnes in 2011. Mean F(2–5 rings) was estimated at 0.4 in 2017, having increased from 0.06 in 2009. Recruitment has been good in recent years with several strong cohorts (2004, 2008, 2009, 2010 and 2013) entering the fishery but has come down substantially in the most recent years with the poorest year class in 2015.The 2017 SSB estimate of 6.a/7.b, c herring (Her.27.6a7bc) the combined stock of 6.aN and 6.aS/7.b, c was 113 000 tonnes, well below Bpa. Continued low recruitment has caused a decline of the stock which is expected to continue in the near future although fishing mortality is low at 0.05–0.1 in recent years.Irish Sea autumn spawning herring (her.27.nirs) assessment shows a stable SSB in 2017 compared to previous years at around 27 000 tonnes. The stock has experienced large incoming year classes in most recent years. Fishing mortality is estimated at the lowest level in the time series at 0.15, below FMSY. Catches have been relatively stable since the 1980s, and close to TAC levels in recent years.North Sea sprat (spr.27.4) is an ICES category 1 stock with a fully accepted analytical assessment. The stock is estimated to be at the highest level since the 1970s in 2018, driven by relatively high recruitment in 2017. The stock appears to be well above Bpa (142 000 tonnes) in 2018 at 408 808 tonnes. Fishing mortality in the last years has fluctuated between 0.4–2.3. A recent management strategy evaluation (WKMSYREF2) suggested that the Bescapement management strategy is not precautionary.Sprat in Division 3.a (spr.27.3a) was benchmarked in 2013 (WKSPRAT), however, it is an ICES category 3 stock that uses three survey series, from which an abundance index is derived, and landings data. ). The surveys show variability over time without a clear trend. The most recent annual change is positive compared to the 4 years before.Catch advice for sprat in the English Channel (7.d, e) (spr.27.7de) was based on criteria for an ICES category 3-based method. Data available are landings and a short time series of acoustic biomass (2013–2017). The acoustic biomass indicates an overall decline in the stock size. Quantitative advice was provided for Sprat in the Celtic Sea (spr.27.67a–cf–k) in 2017 using an ICES category 5-based method where only data on landings are available; this assessment was not updated this year as the advice is still valid and the perception of the stock has not changed. A sprat benchmark is taking place in the summer/autumn of 2018.The HAWG reviewed the assessments performed on seven sandeel stocks and the related advice of these stocks. Section 11 of this report contains the assessments of sandeel in Division 3.a and Subarea 4. Standard issues such as the quality and availability of data, estimating the amounts of discarded fish, availability of data through industry surveys and scientific advances relevant for small pelagic fish were discussed. All data and scripts used to perform the assessment and perform the forecast calculations are available on GitHub and accessible to anyone.

Monitoring n° 29 of PENLY nuclear power - plant takes into account studies between March and September 2016. Hydrology, microbiology, phytoplankton, zooplankton and fishing are studied. This power-plant has been in operation for twenty-six years., La surveillance n° 29 sur le site de PENLY couvre la période de mars à septembre 2016. Les domaines étudiés sont l'hydrologie, la microbiologie, le plancton végétal et animal et le domaine halieutique. L’année 2016 est la vingt septième année de fonctionnement de la centrale.

This is the 39th annual surveillance report concerning the nuclear power plant of Gravelines. Its very high power level results from six plant units located on the shore and is characterised by a cooling system with a coastal surface input and output. The production of electricity began in 1980 and reached a maximum in 1986. Surveys concern monitoring of pelagic system (hydrology, microbiology, phytoplankton, and zooplankton), fish populations (larvae and eggs of Sole and Sprat) or crustaceans (shrimps), and benthic macrofauna (intertidal and subtidal). This survey deals with spatial and temporal approaches (i) study of the direct impact by comparison of the input and output seawater stations, (ii) study of medium and long term evolution of the area by comparison with a reference station., Ce travail constitue le 39e rapport de surveillance du site électronucléaire de Gravelines dont la grande puissance énergétique est assurée par le fonctionnement de 6 tranches. Ce site, implanté sur le littoral, présente une prise d’eau de mer assurant le refroidissement du système et un rejet côtier d’eau réchauffée en surface. Le fonctionnement de la centrale a débuté en 1980 et elle a atteint la puissance maximale en 1986. La surveillance concerne les domaines pélagique (hydrologie, microbiologie, phytoplancton, zooplancton), halieutique (larves et œufs de Sole, de Sprat et crevettes grises), et benthique (intertidal et subtidal). La stratégie de surveillance est basée sur une approche spatiale et temporelle (i) Étude de l’impact immédiat par comparaison de la station « Prise d’eau » et de la station « Canal de rejet » sur une surface limitée (ii) Étude de l’évolution à moyen ou à long terme du milieu marin par rapport à une situation de référence (échelle locale).

This is the 38th annual surveillance report concerning the nuclear power plant of Gravelines. Its very high power level results from six plant units located on the shore and is characterised by a cooling system with a coastal surface input and output. The production of electricity began in 1980 and reached maximum in 1986. Surveys concern monitoring of pelagic system (hydrology, microbiology, phytoplankton, and zooplankton), fish populations (larvae and eggs of Sole and Sprat) or crustaceans (shrimps), and benthic macrofauna (intertidal and subtidal). This survey deals with spatial and temporal approaches (i) study of the direct impact by comparison of the input and output seawater stations, (ii) study of medium and long term evolution of the area by comparison with a reference station., Ce travail constitue le 38e rapport de surveillance du site électronucléaire de Gravelines dont la grande puissance énergétique est assurée par le fonctionnement de 6 tranches. Ce site, implanté sur le littoral, présente une prise d’eau de mer assurant le refroidissement du système et un rejet côtier d’eau chaude en surface. Le fonctionnement de la centrale a débuté en 1980 et elle a atteint la puissance maximale en 1986. La surveillance concerne les domaines pélagique (hydrologie, microbiologie, phytoplancton, zooplancton), halieutique (larves et œufs de Sole, de Sprat et crevettes grises), et benthique (intertidal et subtidal). La stratégie de surveillance est basée sur une approche spatiale et temporelle (i) Étude de l’impact immédiat par comparaison de la station « Prise d’eau » et de la station « Canal de rejet » sur une surface limitée (ii) Étude de l’évolution à moyen ou à long terme du milieu marin par rapport à une situation de référence (échelle locale).

Monitoring n° 29 of PENLY nuclear power - plant takes into account studies between March and September 2015. Hydrology, microbiology, phytoplankton, zooplankton and fishing are studied. This power-plant has been in operation for twenty-six years., La surveillance n° 29 sur le site de PENLY couvre la période de mars à septembre 2015. Les domaines étudiés sont l'hydrologie, la microbiologie, le plancton végétal et animal et le domaine halieutique. L’année 2015 est la vingt sixième année de fonctionnement de la centrale.

Monitoring n° 28 of PENLY nuclear power - plant takes into account studies between March and September 2014. Hydrology, microbiology, phytoplankton, zooplankton and fishing are studied. This power-plant has been in operation for twenty-five years., La surveillance n° 28 sur le site de PENLY couvre la période de mars à septembre 2014. Les domaines étudiés sont l'hydrologie, la microbiologie, le plancton végétal et animal et le domaine halieutique. L’année 2014 est la vingt cinquième année de fonctionnement de la centrale.

This is the 37th annual surveillance report concerning the nuclear power plant of Gravelines. Its very high power level results from six plant units located on the shore and is characterised by a cooling system with a coastal surface input and output. The production of electricity began in 1980 and reached maximum in 1986. Surveys concern monitoring of pelagic system (hydrology, microbiology, phytoplankton, and zooplankton), fish populations (larvae and eggs of Sole and Sprat) or crustaceans (shrimps), and benthic macrofauna (intertidal and subtidal). This survey deals with spatial and temporal approaches (i) study of the direct impact by comparison of the input and output seawater stations, (ii) study of medium and long term evolution of the area by comparison with a reference station., Ce travail constitue le 37e rapport de surveillance du site électronucléaire de Gravelines dont la grande puissance énergétique est assurée par le fonctionnement de 6 tranches. Ce site, implanté sur le littoral, présente une prise d’eau de mer assurant le refroidissement du système et un rejet côtier d’eau chaude en surface. Le fonctionnement de la centrale a débuté en 1980 et elle a atteint la puissance maximale en 1986. La surveillance concerne les domaines pélagique (hydrologie, microbiologie, phytoplancton, zooplancton), halieutique (larves et œufs de Sole, de Sprat et crevettes grises), et benthique (intertidal et subtidal). La stratégie de surveillance est basée sur une approche spatiale et temporelle (i) Etude de l’impact immédiat par comparaison de la station « Prise d’eau » et de la station « Canal de rejet » sur une surface limitée (ii) Etude de l’évolution à moyen ou à long terme du milieu marin par rapport à une situation de référence (échelle locale).

The spring distribution of larval fish stages of flatfishes in the Dover Strait (eastern English Channel) was studied in 1995 and 1999. Fish larvae were identified and sorted according to developmental stages in order to study their ontogenic distribution. The French coastal waters are characterised by an unstable tide-dependent front, which influences larval dispersion. In spring, the French coastal waters have a high phytoplanktonic production. They have higher temperatures, lower salinities and differences in current intensity compared with the central English Channel waters. Generalised Additive Models (GAM) combined with Geographic Information Systems (GIS) were used to model the potential habitats of life stages considering data from three major surveys in this area. The models were developed by coupling presence-absence models with non-null abundance models. The potential habitat of larval stages was then mapped using a geostatistical method (kriging). This revealed different species strategies in which young stages were abundant in central waters and older ones were distributed mainly along the French and Belgian coasts. It is concluded that the central English waters are important for young stages after hatching and that coastal waters are essential nurseries for future juveniles. The models of three flatfish species having similar life cycle strategies are presented here: Limanda limanda, Platichthys flesus and Solea solea. Durante 1995 y 1999 se estudió la distribución primaveral de los estadios larvarios de peces planos en el Estrecho de Dover (parte oriental del Canal de la Mancha).Las larvas de peces fueron identificadas y separadas en función de su estadio de desarrollo con objeto de estudiar su distribución ontogénica. Las aguas costeras francesas se caracterizan por un frente de marea inestable, que influencia la dispersión larvaria. Durante la primavera, dichas aguas presentan una elevada producción fitoplanctónica. Asimismo, presentan altas temperaturas, bajas salinidades y diferencias en la intensidad de la corriente, comparado con las aguas centrales del Canal de la Mancha. A partir de datos obtenidos en tres amplias campañas en este área, se utilizaron Modelos Aditivos Generalizados (GAM) con Sistemas de Información Geográfica (SIG) para modelizar los hábitats potenciales de los estadios larvarios. Los modelos se desarrollaron uniendo modelos de “presencia-ausencia” con modelos de “abundancia no nula”. A continuación, usando métodos geoestadísticos (kriging) se representó el mapa del hábitat potencial de los estadios larvarios. Esto reveló diferencias en las estrategias de aquellas especies cuyos primeros estadios son abundantes en las aguas centrales y cuyos estadios más avanzados están distribuidos principalmente a lo largo de la costa francesa y belga. Se mostró la importancia de las aguas centrales del Canal de la Mancha para las larvas lecitotróficas, y como las aguas costeras son áreas de cría esenciales para los futuros juveniles. Aquí se presentan los modelos para tres especies de peces planos que tienen estrategias de vida similares: Limanda limanda, Platichthys flesus and Solea solea.

This is the 36th annual surveillance report concerning the nuclear power plant of Gravelines. Its very high power level results from six plant units located on the shore and is characterised by a cooling system with a coastal surface input and output. The production of electricity began in 1980 and reached maximum in 1986. Surveys concern monitoring of pelagic system (hydrology, microbiology, phytoplankton, and zooplankton), fish populations (larvae and eggs of Sole and Sprat) or crustaceans (shrimps), and benthic macrofauna (intertidal and subtidal). This survey deals with spatial and temporal approaches (i) study of the direct impact by comparison of the input and output seawater stations, (ii) study of medium and long term evolution of the area by comparison with a reference station., Ce travail constitue le 36e rapport de surveillance du site électronucléaire de Gravelines dont la grande puissance énergétique est assurée par le fonctionnement de 6 tranches. Ce site, implanté sur le littoral, présente une prise d’eau de mer assurant le refroidissement du système et un rejet côtier d’eau chaude en surface. Le fonctionnement de la centrale a débuté en 1980 et elle a atteint la puissance maximale en 1986. La surveillance concerne les domaines pélagique (hydrologie, microbiologie, phytoplancton, zooplancton), halieutique (larves et oeufs de Sole, de Sprat et crevettes grises), et benthique (intertidal et subtidal). La stratégie de surveillance est basée sur une approche spatiale et temporelle (i) Etude de l’impact immédiat par comparaison de la station « Prise d’eau » et de la station « Canal de rejet » sur une surface limitée (ii) Etude de l’évolution à moyen ou à long terme du milieu marin par rapport à une situation de référence (échelle locale).

This is the 35th annual surveillance report concerning the nuclear power plant of Gravelines. Its very high power level results from six plant units located on the shore and is characterised by a cooling system with a coastal surface input and output. The production of electricity began in 1980 and reached maximum in 1986. Surveys concern monitoring of pelagic system (hydrology, microbiology, phytoplankton, and zooplankton), fish populations (larvae and eggs of Sole and Sprat) or crustaceans (shrimps), and benthic macrofauna (intertidal and subtidal). This survey deals with spatial and temporal approaches (i) study of the direct impact by comparison of the input and output seawater stations, (ii) study of medium and long term evolution of the area by comparison with a reference station., Ce travail constitue le 35e rapport de surveillance du site électronucléaire de Gravelines dont la grande puissance énergétique est assurée par le fonctionnement de 6 tranches. Ce site, implanté sur le littoral, présente une prise d’eau de mer assurant le refroidissement du système et un rejet côtier d’eau chaude en surface. Le fonctionnement de la centrale a débuté en 1980 et elle a atteint la puissance maximale en 1986. La surveillance concerne les domaines pélagique (hydrologie, microbiologie, phytoplancton, zooplancton), halieutique (larves et œufs de Sole, de Sprat et crevettes grises), et benthique (intertidal et subtidal). La stratégie de surveillance est basée sur une approche spatiale et temporelle (i) Etude de l’impact immédiat par comparaison de la station « Prise d’eau » et de la station « Canal de rejet » sur une surface limitée (ii) Etude de l’évolution à moyen ou à long terme du milieu marin par rapport à une situation de référence (échelle locale).

Monitoring n° 26 of PENLY nuclear power - plant takes into account studies between March and September 2012. Hydrology, microbiology, phytoplankton, zooplankton and fishing are studied. This power-plant has been in operation for twenty three years., La surveillance n° 26 sur le site de PENLY couvre la période de mars à septembre 2012. Les domaines étudiés sont l'hydrologie, la microbiologie, le plancton végétal et animal et le domaine halieutique. L’année 2012 est la vingt troisième année de fonctionnement de la centrale.

This is the 34th annual surveillance report concerning the nuclear power plant of Gravelines. Its very high power level results from six plant units located on the shore and is characterised by a cooling system with a coastal surface input and output. The production of electricity began in 1980 and reached maximum in 1986. Surveys concern monitoring of pelagic system (hydrology, microbiology, phytoplankton, zooplankton), fish populations (larvae and eggs of Sole and Sprat) or crustaceans (shrimps), and benthic macrofauna (intertidal and subtidal). This survey deals with spatial and temporal approaches (i) study of the direct impact by comparison of the input and output seawater stations, (ii) study of medium and long term evolution of the area by comparison with a reference station., Ce travail constitue le 34e rapport de surveillance du site électronucléaire de Gravelines dont la grande puissance énergétique est assurée par le fonctionnement de 6 tranches. Ce site, implanté sur le littoral, présente une prise d’eau de mer assurant le refroidissement du système et un rejet côtier d’eau chaude en surface. Le fonctionnement de la centrale a débuté en 1980 et elle a atteint la puissance maximale en 1986. La surveillance concerne les domaines pélagique (hydrologie, microbiologie, phytoplancton, zooplancton), halieutique (larves et œufs de Sole, de Sprat et crevettes grises), et benthique (intertidal et subtidal). La stratégie de surveillance est basée sur une approche spatiale et temporelle (i) Etude de l’impact immédiat par comparaison de la station « Prise d’eau » et de la station « Canal de rejet » sur une surface limitée (ii) Etude de l’évolution à moyen ou à long terme du milieu marin par rapport à une situation de référence (échelle locale).

This is the 33th annual surveillance report concerning the nuclear power plant of Gravelines. Its very high power level results from six plant units located on the shore and is characterised by a cooling system with a coastal surface input and output. The production of electricity began in 1980 and reached maximum in 1986. Surveys concern monitoring of pelagic system (hydrology, microbiology, phytoplankton, zooplankton), fish populations (larvae and eggs of Sole and Sprat) or crustaceans (shrimps), and benthic macrofauna (intertidal and subtidal). This survey deals with spatial and temporal approaches (i) study of the direct impact by comparison of the input and output seawater stations, (ii) study of medium and long term evolution of the area by comparison with a reference station., Ce travail constitue le 33e rapport de surveillance du site électronucléaire de Gravelines dont la grande puissance énergétique est assurée par le fonctionnement de 6 tranches. Ce site, implanté sur le littoral, présente une prise d’eau de mer assurant le refroidissement du système et un rejet côtier d’eau chaude en surface. Le fonctionnement de la centrale a débuté en 1980 et elle a atteint la puissance maximale en 1986. La surveillance concerne les domaines pélagique (hydrologie, microbiologie, phytoplancton, zooplancton), halieutique (larves et oeufs de Sole, de Sprat et crevettes grises), et benthique (intertidal et subtidal). La stratégie de surveillance est basée sur une approche spatiale et temporelle (i) Etude de l’impact immédiat par comparaison de la station « Prise d’eau » et de la station « Canal de rejet » sur une surface limitée (ii) Etude de l’évolution à moyen ou à long terme du milieu marin par rapport à une situation de référence (échelle locale).

The processes that control the spatial distribution of North Sea whiting (Merlangius merlangus) spawning adults are investigated using a statistical multi-model approach. Models of external and internal controls on the population, such as environmental conditions, spatial constraints, present or past spatial distribution, and demographic state of the population, are evaluated, compared and ranked to select those that are the best able to predict the observed distribution of spawning adults. Model selection is greatly influenced by the selection method, either based on data fitting or prediction, as well as by the threshold value used to stop the selection. Model selection based on prediction tends to select simpler models than selection based on data fitting. The hypotheses underlying the selected models are inferred to play a significant role in controlling North Sea whiting spatial distribution. The multi-model inference approach developed in this study enables comparison of several theoretical concepts and hypotheses and the results provide important clues on the processes involved in the control of the spatial distribution of whiting. We conclude that whiting has a high spatial fidelity to spawning site which can be linked to either geographical attachment or year-to-year persistence of the spatial distribution of the population. Environmental factors - temperature and salinity - appear to influence the geographical extent of spawning whiting distribution, whereas local abundance levels are primarily controlled by internal factors, i.e., population size and spatial segregation between ages.

Understanding and predicting the distribution of organisms in heterogeneous environments lies at the heart of ecology. The spatial distribution of fish populations observed in the wild results from the complex interactions of multiple controls both external or internal to the fish populations. Whilst species distribution models (SDMs) have been mostly concerned with static description of species distribution as a function of environmental constraints, models of animal movements (MAMs) have focussed on the dynamic nature of spatial distribution of groups of individuals under a number of constraints external and internal to the population. Besides SDMs and MAMs, modelling the spatial distribution of fish populations can be achieved by models that are fundamentally static (like SDMs) but can also incorporate many hypotheses on the control of fish spatial distribution (like MAMs). The hypotheses underlying these models need to make sense at the population level - rather than at the individual or species level –we term these‘population distribution models’ (PDMs). PDMs are statistical models that rely on several hypotheses, which include: (i) control through geographical attachment, (ii) environmental conditions, (iii) density- dependent habitat selection, (iv) spatial dependency, (v) population demographic structure, (vi) species interactions and (vii) population memory. We review the basis behind each of these conceptual models and we examine corresponding numerical applications. We argue that the conceptual models are complementary rather than competing, that existing numerical applications are still rarely compared and combined, and that PDMs can offer a statistical framework to achieve this. We recommend that the numerical models associated with different hypotheses be constructed within such a common general framework. This will permit evaluation, comparison and combination of the multiple hypotheses on fish spatial distribution. It will ultimately lead to a more comprehensive understanding of the factors controlling the spatial distribution of fish populations and to more accurate predictions in which model uncertainty is accounted for.

The spatial distributions of spawning population of North Sea plaice and whiting were studied using geostatistical analyses. Variograms were computed each year since 1980 on abundance data of spawning adults using the first quarter data from the International Bottom Trawl Survey. Maps of spatial distribution of spawning adults were produced using kriging interpolation. For both species, distributions of spawning adults were in agreement with historical spawning grounds previously described from location of their eggs. This showed that spawning adults distribution may be used to infer the distribution of both plaice during its spawning peak and whiting at the beginning of its spawning period. Both species were strongly spatially structured with abundances of spawning adults located in particular areas. Spawning plaice was mainly located in the southern North Sea and along the east coast of the United Kingdom whereas it was virtually absent in the central part of the North Sea. For whiting, recurrent spawning sites were found both to the north and south of the Dogger Bank whereas the central and eastern parts of the North Sea were less suitable for spawning. Although this pattern of distribution remained stable in the last thirty years at the scale of the North Sea, multivariate analysis revealed a shift in the centre of distribution of spawning adults for both species. Changes in the extent of plaice spawning areas may be explained by temporal evolution of its spawning biomass. However, for whiting, the mechanisms responsible for the observed variations remain unclear.

International symposium on “Climate change effects on fish and fisheries: Forecasting impacts, assessing ecosystem responses and evaluating management strategies” from April 26–29, 2010, in Sendai, Japan.

Spawning is an important phase for short-lived species like anchovy (Engraulis encrasicolus) as it ensures the renewal of the population through the recruitment process. Data from the PELGAS (PELagiques GAScogne) surveys, taking place since 2000 in the Bay of Biscay, were used to identify the controls of anchovy spawning distribution. Six ecological concepts underlying fish distribution were taken into account. Two are external to the population - environment and site attachment - and four are internal to the population: spatial dependency, population size, demographic structure, and population memory. Each of these ecological hypotheses was represented by one or several explanatory variables that were related to both presence–absence and positive abundance of anchovy using generalized additive models. Models were evaluated into a multi-model approach framework using a distance measure between model predictions and real observations. The Akaike Information Criterion and the log-likelihood were used for measuring model adjustment and prediction capacity. Models were ranked and selected according to these distances and hypotheses that were present in selected models were determined as relevant to explaining spawning anchovy distribution. Presence–absence was mainly determined by physiologically constraining environmental conditions such as temperature and large-scale spatial dependency, whereas inside the areas of presence, positive abundances were determined by trophic conditions, suitable for the successive maturations of the gonads, and population structure such as age‐segregation patterns. The results of this study may show that homing could be a key mechanism that ensures a successful return of the adults to the same spawning areas year after year.