Search

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.

Spawning is a crucial phase of fish life cycle as it ensures the renewal of individuals in the population. The identification of factors that influence its spatial dynamic is therefore a key feature as it will affect the reproduction success of fish population. A multi-model approach has been developed in order to identify factors that control the spatial distribution of spawning adults of plaice and whiting in the North Sea and of anchovy in the Bay of Biscay. Generalised additive models have been used to relate presenceabsence of adults and their abundances to several hypotheses of control external (geographical position and environment) and internal to the population (spatial dependency, size, age structure and memory). Models were then ranked according to their ability to reflect theobserved distribution. Relevant hypotheses of control were then identified from the best models. The spawning habitat depicts a strong spatial structure. The multi-model approach highlights that (1) environmental factors influence the occupation of spawning areas and (2) population internal factors determine the degree of abundance by which spawning areas are occupied. Temporal persistence of spawning distribution is ensured by attachment of adults to their spawning site. This attachment is stronger for bentho-demersal fish like plaice and whiting than for pelagic fish like anchovy., La reproduction est une phase importante du cycle de vie des poissons car elle assure le renouvellement du nombre d'individus dans la population. La détermination des facteurs qui influencent sa dynamique spatiale est donc un point capital car elle affecte le succès de la reproduction.Une approche multi-modèles a été développée afin d'identifier les facteurs contrôlant la distribution spatiale des adultes reproducteurs pour la plie et le merlan de Mer du Nord et pour l'anchois du Golfe de Gascogne. Les modèles additifs généralisés ont été utilisés pour relier la présence-absence des individus et leurs abondances aux différentes hypothèses de contrôle externes (position géographique et environnement) et internes à la population (dépendance spatiale, taille, structure en âge et mémoire). Les modèles construits ont été classés en fonction de leur aptitude à refléter les distributions observées. Les hypothèses de contrôle importantes ont alors été identifiées à partir des meilleurs modèles. L'habitat de reproduction montre une structuration très importante dans l'espace. L'approche multi-modèles révèle (1) l'influence de l'environnement sur l'occupation des zones de reproduction et (2) le degré d'abondance avec lequel ces zones sont occupées est déterminé par des facteurs internes à la population. La persistance dans le temps de la structuration spatiale de la reproduction est facilitée par un attachement des individus à leur site de reproduction. Celui ci est plus fort pour des bentho-démersaux comme la plie et le merlan que pour un pélagique comme l'anchois.

INTRODUCTION: The Dover Strait (Figure 1) connects the North Sea to the English Channel. Here, northern France and South-East England are at their closest. This narrow corridor, one of the world's busiest straits for maritime shipping, is a key economic area for numerous activities, such as leisure and tourism, international ports and shipping, plus the exploitation of living or abiotic marine resources. This area is a significant resource for fisheries because many commercial fish species are abundant there, but also because of the presence of nursery and spawning areas and migratory routes linked to specific environmental characteristics. The vulnerability of these resources, which are subjected to strong anthropogenic pressures, has brought together French and British maritime experts within a common project: to create an atlas of marine resource habitats in the Eastern English Channel. The first phase of the project focuses on the Dover Strait. Why the need for an atlas of marine resource habitats? Because the primary aim of the atlas is to act as a contemporary reference source for the Dover Strait marine environment and provide decision-makers with the necessary information to help in the management of marine living resources. Furthermore, it is essential that France and the United Kingdom have a common vision for the protection of ecosystems quality and for the utilisation of the marine resources shared by these two countries, which are presently suffering the consequences of the decline in the abundance of certain species. Sensible management, assisted by information systems and tools to help decision-making, is the key for the sustainable use of these resources. Finally, the popularisation of these approaches amongst the wider public is also an important factor in increasing the awareness of stakeholders and other users, and to involve them in the preservation and protection of a natural heritage, for a sustainable management of these resources. Why habitats? Because a habitat is an area where the environmental conditions are suitable for an organism, a population or a community to survive and live in a spontaneous state. As a result, any alteration of the environment may have disastrous consequences. Habitats and living marine resources in this geographical area are essential from the point of view of the environment because they contribute to the functioning of this unique ecosystem. This atlas is first of all an assessment of available and usable data for this approach. It presents a descriptive analysis of the environment of the Dover Strait and its resources (benthic assemblages, marine fish species: larvae, juvenile and adult). Also presented are the methods used to analyse these data and to map the suitable habitat for 16 marine fish species., INTRODUCTION: Le Détroit du Pas-de-Calais (figure 1) est à la jonction entre la mer du Nord et la Manche. Rapprochant à l'extrême le Nord de la France et le Sud-Est de l'Angleterre, ce couloir étroit est une des zones où le trafic maritime est le plus intense du monde ; il représente ainsi une zone économique importante utilisée pour de nombreuses activités : tourisme et loisirs, ports internationaux et fret, exploitation de ressources vivantes ou non. C'est un secteur très riche pour la pêche professionnelle car on y trouve de nombreuses espèces commerciales, des zones de nourriceries et de frayères, des voies de migration, liées à des paramètres environnementaux caractéristiques. La fragilité de ces ressources marines, soumises à de fortes pressions anthropiques, a incité les spécialistes français et britanniques du domaine maritime à se regrouper autour d'un projet commun : réaliser un atlas des habitats des ressources marines de la Manche orientale, dont la première phase focalise principalement sur le Détroit du Pas-de- Calais. Pourquoi un atlas sur les habitats de ces ressources ? Parce que le but de ce projet est de fournir aux collectivités un outil d'aide à la décision leur permettant de mieux appréhender la complexité du monde marin afin d'aider, en concertation avec les scientifiques, à la gestion des ressources vivantes marines du Détroit du Pas de Calais et la planification de certains aménagements en évaluant leurs conséquences sur ces ressources. D'autre part, il est essentiel que la France et le Royaume-Uni aient une vision commune de la protection de la qualité des écosystèmes et de l'utilisation des ressources marines partagées par ces deux pays qui subissent les conséquences de la diminution d'abondance de certaines espèces. Il est vrai qu'une gestion raisonnée assistée par des systèmes d'informations et des outils aidant à la décision représente un atout indéniable pour une exploitation durable de ces ressources. Enfin, la vulgarisation de ces approches auprès du grand public est aussi un facteur important afin de sensibiliser tous les acteurs et utilisateurs et les impliquer dans la préservation et la sauvegarde d'un patrimoine naturel pour une gestion durable de ces richesses. Pourquoi les habitats ? Parce que l'habitat est le lieu regroupant l'ensemble des conditions environnementales dans lequel un organisme, une population ou une communauté peut survivre et se maintenir à l'état spontané. Par conséquent, la moindre modification de l'environnement peut avoir des conséquences dramatiques. Les habitats et les ressources marines vivantes de cette région sont essentiels d'un point de vue environnemental car ils participent au bon fonctionnement de cet écosystème unique. Cet atlas fait tout d'abord un état des lieux des données disponibles et utilisables pour cette approche. Il présente une analyse descriptive de l'environnement du Détroit du Pas-de-Calais et de ses ressources (peuplements benthiques, espèces halieutiques larvaires, juvéniles et adultes). Sont aussi présentées les méthodes utilisées pour traiter ces données et pour réaliser la cartographie des habitats préférentiels de 16 espèces halieutiques d'intérêt commercial.

Valuable marine habitats and living resources can be found in the Eastern English Channel and in 2003, a Franco-British Interreg IIIA project, ‘Eastern Channel Habitat Atlas for Marine Resource Management’ (CHARM), was initiated to support decision-making for management of essential fish habitats. Fish habitat corresponds to geographic areas within which ranges of environmental factors define the presence of a particular species. Habitat Suitability index (HSI) modelling was used to relate fish geographic distribution and their relation towards environmental factors and to delineate their optimum habitat. This study was based on data obtained from 1988-2003 IFREMER’s Channel Ground Fish Surveys, including both species abundance and environmental data. Suitability index (SI) functions based on generalised additive models were used to relate depth, temperature, salinity and sediment to sub-community assemblage probability of occurrence. As a result, SI values were positively related to assemblage affinity along the gradient of the environmental variables. The resulting HSI models were used to map, using GIS, the optimum habitats of communities ; sensible habitats such as spawning grounds, nurseries or areas carrying bio-diverse fish community were also defined. The information obtained will help to elaborate guidelines for the conservation and protection of natural habitats in the face of climate change and anthropogenic disturbances.

This annual report on ecological and fishery monitoring (n °35) of the Nuclear Power Plant (NPP) of Penly (Seine-Maritime department) concerns the year 2021. 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 the NPP and its area of influence). The year 2021 is the 32th year of operation of the NPP in Penly (entry into operation of the NPP 1989)., Ce rapport annuel de la surveillance écologique et halieutique (n°35) du Centre Nucléaire de Production d'Électricité de Penly (département de Seine Maritime) concerne l'année 2021. 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 2021 est la 32e année de fonctionnement du CNPE de Penly (mise en fonctionnement du CNPE 1989).

The aim of this study was to characterize the feeding strategy of Downs herring larvae at "critical period" during winter in the English Channel and North Sea was defined to assess whether nutrition is responsible for low recruitment in stocks over the past years. Data collected during the French part of the International Bottom Trawl Survey from 2008 to 2014 were used to analyse fish larvae diet by direct observation using Scanning Electron Microscope (SEM). Gut content methods generally used for copepods was adapted to fish larvae to assess phytoplankton ingestion. The relative importance of small preys (0,5-375µm) observed in gut contents proved the essential role of SEM to better acknowledge Downs herring diet. We demonstrated that Downs herring larvae from 6 to 20 mm were omnivorous, specialized on invertebrate eggs and more rarely consumed a variety of phytoplankton and zooplankton prey. They also seemed to positively select rare phytoplankton prey whereas they negatively select several zooplankton prey.

This annual report on ecological and fishery monitoring (n°43) of the Electrique Nuclear Production Center (CNPE) in Gravelines (Nord department) concerns the year 2020. This monitoring, which started in 1978, relates to the Pelagic (hydrology, microbiology, phytoplankton, zooplankton), Fishery (larvae and eggs of sole, sprat and grey shrimps) and Benthic (intertidal and subtidal) 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 40th year of operation of the CNPE in Gravelines (entry into operation of the CNPE in 1980)., Ce rapport annuel de la surveillance écologique et halieutique (n°43) du Centre Nucléaire de Production Electrique de Gravelines (département du Nord) concerne l’année 2020. Cette surveillance, qui a débuté en 1978, porte sur les compartiments Pélagique (hydrologie, microbiologie, phytoplancton, zooplancton), Halieutique (larves et oeufs de sole, de sprat et crevettes grises), et Benthique (intertidal et subtidal). 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 du CNPE et de sa zone d’influence). L'année 2020 est la 40ème année de fonctionnement du CNPE de Gravelines (mise en fonctionnement du CNPE en 1980).