Search

Your search keyword '"Safi, Georges"' showing total 39 results
Start Over Author "Safi, Georges"
39 results on '"Safi, Georges"'

3. Toward an Ecosystem Approach of Marine Renewable Energy: The Case of the Offshore Wind Farm of Courseulles-sur-Mer in the Bay of Seine

Author

Niquil, Nathalie, Raoux, Aurore, Haraldsson, Matilda, Araignous, Emma, Halouani, Ghassen, Leroy, Boris, Safi, Georges, Noguès, Quentin, Grangeré, Karine, Dauvin, Jean-Claude, Riera, Fabien, Mazé, Camille, Le Loc’h, François, Ching Villanueva, M., Hattab, Tarek, Bourdaud, Pierre, Champagnat, Juliette, Lasram, Frida Ben Rais, Kostianoy, Andrey G., Series Editor, Nguyen, Kim Dan, editor, Guillou, Sylvain, editor, Gourbesville, Philippe, editor, and Thiébot, Jérôme, editor

Published
2020
Full Text
View/download PDF

14. Potential combined impacts of climate change and non-indigenous species arrivals on Bay of Biscay trophic network structure and functioning

Author

Le Marchand, Marie, Ben Rais Lasram, F., Araignous, Emma, Saint-béat, Blanche, Lassalle, G., Michelet, Nicolas, Serre, S., Safi, Georges, Lejart, Morgane, Niquil, N., Le Loch, Francois, Le Marchand, Marie, Ben Rais Lasram, F., Araignous, Emma, Saint-béat, Blanche, Lassalle, G., Michelet, Nicolas, Serre, S., Safi, Georges, Lejart, Morgane, Niquil, N., and Le Loch, Francois

Abstract

The consequences of climate change for marine organisms are now well-known, and include metabolism and behavior modification, distribution area shifts and changes in the community. In the Bay of Biscay, the potential environmental niches of subtropical non-indigenous species (NIS) are projected to expand as a response to sea temperature rise by the mid-century under the RCP8.5 climate change scenario. In this context, this study aims to project the combined effects of changes in indigenous species distribution and metabolism and NIS arrivals on the functioning of the Bay of Biscay trophic network. To do this, we created six different Ecopath food web models: a “current situation” trophic model (2007–2016) and five “future” trophic models. The latter five models included various NIS biomass combinations to reflect different potential scenarios of NIS arrivals. For each model, eight Ecological Network Analysis (ENA) indices were calculated, describing the properties of the food web resulting from the sum of interactions between organisms. Our results illustrate that rising temperature increases the quantity of energy passing through the system due to increased productivity. A decrease in the biomass of some trophic groups due to the reduction of their potential environmental niches also leads to changes in the structure of the trophic network. The arrival of NIS is projected to change the fate of organic matter within the ecosystem, with higher cycling, relative ascendency, and a chain-like food web. It could also cause new trophic interactions that could lead to competition and thus modify the food-web structure, with lower omnivory and higher detritivory. The combined impacts (increasing temperatures and NIS arrivals) could lower the resilience and resistance of the system.

Published
2022
Full Text
View/download PDF

15. The Response of North Sea Ecosystem Functional Groups to Warming and Changes in Fishing

Author

Department for Environment, Food & Rural Affairs (UK), Arroyo, Nina Larissa [0000-0003-1502-1245], Preciado, Izaskun [0000-0002-0934-9423], Thorpe, Robert B., Arroyo, Nina Larissa, Safi, Georges, Niquil, Nathalie, Preciado, Izaskun, Heath, Michael, Pace, Matthew C., Lynam, Christopher P., Department for Environment, Food & Rural Affairs (UK), Arroyo, Nina Larissa [0000-0003-1502-1245], Preciado, Izaskun [0000-0002-0934-9423], Thorpe, Robert B., Arroyo, Nina Larissa, Safi, Georges, Niquil, Nathalie, Preciado, Izaskun, Heath, Michael, Pace, Matthew C., and Lynam, Christopher P.

Abstract

[EN] Achieving Good Environmental Status (GES) requires managing ecosystems subject to a variety of pressures such as climate change, eutrophication, and fishing. However, ecosystem models are generally much better at representing top-down impacts from fishing than bottom-up impacts due to warming or changes in nutrient loading. Bottom-up processes often have to be parameterised with little data or worse still taken as a system input rather than being represented explicitly. In this study we use an end-to-end ecosystem model (StrathE2E2) for the North Sea with 18 broad functional groups, five resource pools, and representations of feeding, metabolism, reproduction, active migrations, advection, and mixing. Environmental driving data include temperature, irradiance, hydrodynamics, and nutrient inputs from rivers, atmosphere, and ocean boundaries, so the model is designed to evaluate rigorously top-down and bottom-up impacts and is ideal for looking at possible changes in energy flows and “big picture” ecosystem function. In this study we considered the impacts of warming (2 and 4°C) and various levels of fishing, by demersal and pelagic fleets, on the structure and function of the foodweb. A key aim is to demonstrate whether monitoring of broad ecosystem groups could assist in deciding whether GES was being achieved. We found that warming raised primary productivity and increased the size (total biomass) of the ecosystem. Warming raised metabolic demands on omnivorous zooplankton and reduced their abundance, thus favouring benthivorous and piscivorous demersal fish at the expense of planktivorous pelagic fish but otherwise had modest effects on energy pathways and top predators, whereas changes in fishing patterns could materially alter foodweb function and the relative outcomes for top predators. We suggest that GES should be defined in terms of an unfished state and that abundances of broad groupings and the balance between them can help to assess whether indicator

Published
2022

18. Impacts of climate change on the Bay of Seine ecosystem: Forcing a spatio‐temporal trophic model with predictions from an ecological niche model

Author

Bourdaud, Pierre, Ben Rais Lasram, Frida, Araignous, Emma, Champagnat, Juliette, Grusd, Samantha, Halouani, Ghassen, Hattab, Tarek, Leroy, Boris, Noguès, Quentin, Raoux, Aurore, Safi, Georges, Niquil, Nathalie, Bourdaud, Pierre, Ben Rais Lasram, Frida, Araignous, Emma, Champagnat, Juliette, Grusd, Samantha, Halouani, Ghassen, Hattab, Tarek, Leroy, Boris, Noguès, Quentin, Raoux, Aurore, Safi, Georges, and Niquil, Nathalie

Abstract

Climate change is already known to cause irreversible impacts on ecosystems that are difficult to accurately predict due to the multiple scales at which it will interact. Predictions at the community level are mainly focused on the future distribution of marine species biomass using ecological niche modelling, which requires extensive efforts concerning the effects that trophic interactions could have on the realized species dynamics. In this study, a set of species distribution models predictions were used to force the spatially‐explicit trophic model Ecospace in order to evaluate the potentials impacts that two 2,100 climate scenarios, RCP2.6 and RCP8.5, could have on a highly exploited ecosystem, the Bay of Seine (France). Simulations demonstrated that both scenarios would influence the community of the Bay of Seine ecosystem: as expected, more intense changes were predicted with the extreme scenario RCP8.5 than with the RCP2.6 scenario. Under both scenarios, a majority of species underwent a decrease of biomass, although some increased. However, in both cases the stability of the majority of species dynamics was lowered, the sustainability of the fishery. Differences between niche modelling predictions and those obtained through the forcing in Ecospace highlighted the paramount importance of considering trophic interactions in climate change simulations. These results illustrate the requirement of multiplying novel approaches for efficiently forecasting potential impacts of climate change.

Published
2021
Full Text
View/download PDF

19. Recommandations for the quantitative assessment of metal inputs in the marine environment from the galvanic anodes of offshore renewable energy structures

Author

Michelet, Nicolas, Julian, Nais, Duarte, Rui, Burgeot, Thierry, Amouroux, Isabelle, Dallet, Melissa, Caplat, Christelle, Gonzalez, Jean-louis, Garreau, Pierre, Aragon, Emmanuel, Perrin, Francois-xavier, Safi, Georges, Michelet, Nicolas, Julian, Nais, Duarte, Rui, Burgeot, Thierry, Amouroux, Isabelle, Dallet, Melissa, Caplat, Christelle, Gonzalez, Jean-louis, Garreau, Pierre, Aragon, Emmanuel, Perrin, Francois-xavier, and Safi, Georges

Abstract

The fast-growing offshore wind industry represents a potential new anthropogenic pressure for the marine environment. Despite the fact that it is considered as a green/clean energy source, the large-scale deployment of these devices could induce some environmental impacts that need to be studied. Understanding these impacts is in line with the Marine Strategy Framework Directive (MSFD) (European Commission, 2008) of the European Union which targets good environmental status for the marine environment. The development of offshore renewable energies (ORE), in particular floating and fixed offshore wind structures in France, gives rise to new and more precise questioning from the French public authorities and civil society. In particular, a lot of questions have emerged in relation to the use of Galvanic Anode Cathodic Protection (GACP) systems and about the release of heavy metals associated with their functioning. These anodes are composed of different metals which are more reducing than the metal to be protected. The anodes are generally made with magnesium, aluminium or zinc. In offshore industries such as offshore wind turbines or oil & gas platforms, the anodes used are mainly composed of an aluminium alloy which contains zinc and other trace metals. Their installation in fishing zones is a source of major concern and this affects several offshore wind farm projects (such as Île d’Yeu and Noirmoutier). This growing concern from public authorities and civil society has even led to galvanic anodes being abandoned in certain projects in order to overcome this problem. For example, the chosen solution for the jacket foundations of the Dieppe Le Tréport project is to implement cathodic protection by impressed current (ICCP) with titanium anodes). GACP has been replaced by ICCP in several projects although no scientific study has been conducted to prove the environmental impact of GACP in the ORE context, and no scientific study has proven that ICCP has no environment

Published
2020

20. Impacts of climate change on the Bay of Seine ecosystem: Forcing a spatio‐temporal trophic model with predictions from an ecological niche model

Author

Bourdaud, Pierre, primary, Ben Rais Lasram, Frida, additional, Araignous, Emma, additional, Champagnat, Juliette, additional, Grusd, Samantha, additional, Halouani, Ghassen, additional, Hattab, Tarek, additional, Leroy, Boris, additional, Noguès, Quentin, additional, Raoux, Aurore, additional, Safi, Georges, additional, and Niquil, Nathalie, additional

Published
2021
Full Text
View/download PDF

21. Indices ENA et approche holistique des écosystèmes : application à la baie de Seine, espace de cumul d’activités humaines autour du futur parc éolien

Author

Noguès, Quentin, Bourdaud, Pierre, Araignous, Emma, Champagnat, Juliette, Foucher, Eric, Halouani, Ghassen, Hattab, Tarek, Ben, Frida, Lasram, Rais, Le Loc'H I, François, Leroy, Boris, Raoux, Aurore, Robin, Jean-Paul, Safi, Georges, Villanueva, Ching-Maria, Dauvin, Jean-Claude, Niquil, Nathalie, and Raoux, Aurore

Subjects
[SDE.BE] Environmental Sciences/Biodiversity and Ecology
Abstract

Le niveau trophique moyen (MTL) est couramment utilisé pour caractériser la structure des écosystèmes marins exploités et évaluer leur état de santé. Afin d’atteindre une description plus complète du fonctionnement des écosystèmes, il peut être complété par les indices ENA (Ecological Network Analysis). Ces derniers caractérisent les propriétés émergentes des écosystèmes, reliées par les théories écologiques, à stabilité et la maturité des systèmes. Il existe un grand nombre d’indices ENA, comme le recyclage, l’efficacité de transfert trophique ou encore le rapport détritivorie / herbivorie. Pour étudier le cumul de l’effet du changement climatique avec celui attendu de l’implantation d’éoliennes offshore en baie de Seine, un modèle Ecospace, composé de cellules d’un mille marin de côté, a été créé, du trait de côte jusqu’à la limite de la zone économique exclusive française. Le modèle est utilisé pour simuler l’effet du réchauffement climatique par l’intégration de résultats de modèles de niches écologiques, et l’effet du parc éolien offshore par l’effet réserve qu’il induit. Nous pouvons ainsi calculer des cartes d’indices ENA afin de comprendre les conséquences du cumul d’impacts sur l’écosystème de la baie de Seine. Même si la réponse varie en fonction de l’échelle spatiale considérée, l’effet du changement climatique domine, engendrant une baisse importante de la biomasse des 44 espèces considérées dont 27 espèces de poissons. Les indices ENA les plus sensibles à l’effet changement climatique sont le rapport D/H et l’efficacité de transfert trophique, ce dernier et le recyclage étant les plus sensibles à l’effet réserve. Le modèle permet ainsi de comparer l’évolution du service d’approvisionnement halieutique avec les propriétés émergentes, de l’écosystème.

Published
2019

22. Vers une approche socio-écosystémique des EMR : combiner les modèles pour caractériser les impacts du changement climatique, de la pêche et du futur parc éolien de Baie de Seine

Author

Niquil, Nathalie, Araignous, Emma, Ben, Frida, Lasram, Rais, Bourdaud, Pierre, Champagnat, Juliette, Grangeré, Karine, Halouani, Ghassen, Haraldsson, Matilda, Hattab, Tarek, Le Loc'H J, François, Leroy, Boris, Noguès, Quentin, Raoux, Aurore, Robin, Jean-Paul, Safi, Georges, Villanueva, Ching-Maria, Dauvin, Jean-Claude, and Raoux, Aurore

Subjects
[SDE.BE] Environmental Sciences/Biodiversity and Ecology
Abstract

Les études environnementales réalisées en amont des projets éoliens offshores permettent de mettre en évidence leurs impacts potentiels, en s’attachant à considérer la sensibilité aux perturbations de chacun des compartiments écologiques (benthos, poissons, oiseaux, mammifères marins etc), de façon fractionnée. Le projet TROPHIK porte sur l’impact du futur parc éolien au large de Courseulles-sur-mer, cumulé avec ceux des changements climatiques et de la pêche. Avec ce projet nous avons développé une vue d’ensemble, intégrée, par la mise en place d’outils de modélisation, complémentaires aux approches utilisées lors des études d’impact. Nous avons considéré le réseau trophique et le socio-écosystème dans son ensemble, en combinant différents modèles. La modélisation de niches écologiques a permis de simuler le probable déplacement des espèces de la Manche selon les scénarios du GIEC (Groupe d'experts intergouvernemental sur l'évolution du climat). L’analyse inverse linéaire (LIM-MCMC) a permis une modélisation en 0D du site du parc. Les scénarios ont pu combiner les effets du changement climatique et les effets récifs et réserve associés à la construction du parc, tout en appliquant les indices ENA (analyse des réseaux écologiques) avec une quantification de leur incertitude. Le modèle Ecopath-Ecosim-Ecospace, a permis de modéliser le réseau trophique en 2D sur toute la baie de Seine étendue jusqu’à la frontière franco-britannique, et de réaliser différents scénarios ayant pour sorties des cartes d’indices ENA. Enfin, la modélisation qualitative en digraphes orientés des socio-écosystèmes a permis de faire un pas vers une intégration équilibrée des réseaux d’interactions entre acteurs et espèces. Cette combinaison d’approches constitue un socle, transférable à toute situation similaire d’impacts en mer, qui sera présenté avec différentes recommandations tirées du projet.

Published
2019

23. Recommandations pour une approche écosystémique des aires d’implantation d’énergies marines renouvelables. Cas d’étude du parc éolien offshore de Courseulles-sur-mer

Author

Araignous, Emma, Beaugrand, Gregory, Ben Rais Lasram, Frida, Bourdaud, Pierre, Champagnat, Juliette, Dauvin, Jean-claude, Grangeré, Karine, Halouani, Ghassen, Haraldsson, Matilda, Hattab, Tarek, Le Loch, Francois, Leroy, Boris, Lejart, Morgane, Niquil, Nathalie, Nogues, Quintin, Pagot, J.-p., Raoux, Aurore, Safi, Georges, Villanueva, Ching-maria, Araignous, Emma, Beaugrand, Gregory, Ben Rais Lasram, Frida, Bourdaud, Pierre, Champagnat, Juliette, Dauvin, Jean-claude, Grangeré, Karine, Halouani, Ghassen, Haraldsson, Matilda, Hattab, Tarek, Le Loch, Francois, Leroy, Boris, Lejart, Morgane, Niquil, Nathalie, Nogues, Quintin, Pagot, J.-p., Raoux, Aurore, Safi, Georges, and Villanueva, Ching-maria

Abstract

Les études d’impact environnemental menées en amont des projets éoliens offshores considèrent chaque compartiment de manière individuelle, et non pas l’écosystème dans son ensemble. La compréhension des liens trophiques et l’appréhension de l’écosystème de manière holistique est pourtant un enjeu important rapporté par les politiques publiques telles que la Directive Cadre Stratégie pour le Milieu Marin (Directive 2008/56/EC). Le projet collaboratif TROPHIK (ANR-10-IEED-0006-12) pose les bases d’une approche écosystémique des Energies Marines Renouvelables (EMR) destinée à permettre une démarche holistique et intégrée avant installation de parcs éoliens en mer. Cette approche s’appuie sur un cas d’étude français, le site du futur parc éolien au large de Courseulles-sur-mer développé par le consortium « Parc éolien en mer du Calvados ». Le réseau trophique est considéré dans sa globalité, du plancton aux prédateurs supérieurs (oiseaux et mammifères marins), de la baie de Seine jusqu’à la zone économique exclusive française. Différentes approches de modélisations abordant plusieurs dimensions ont été utilisées et/ou développées afin d’appréhender les effets directs et indirects des EMR de manière holistique. Elles permettent également l’intégration de ces dispositifs de récupération d’énergie dans un contexte plus global de cumul d’impacts et au sein d’un réseau socio-écologique. La première partie de cet ouvrage est consacrée à des fiches récapitulatives présentant l’objectif, la méthode et les résultats principaux du projet ainsi que les personnes impliquées dans la valorisation scientifique qui en a découlé. Dans l’optique de la mise en place d’une approche écosystémique des EMR, la seconde partie recense les recommandations et perspectives issues de ces travaux afin de contribuer à l’étude et à l’amélioration de la compréhension des effets liés à l’intégration de nouvelles infrastructures dans les écosystèmes marins.

Published
2019

24. Towards coherent GES assessments at sub-regional level: signs of fisheries expansion processes in the Bay of Biscay using an OSPAR food web indicator, the Mean Trophic Level.

Author

Arroyo, Nina Larissa, Safi, Georges, Vouriot, Pauline, López-López, Lucía, Niquil, Nathalie, leloc'h, Francois, Hatab, Tarek, Preciado, Izaskun, Arroyo, Nina Larissa, Safi, Georges, Vouriot, Pauline, López-López, Lucía, Niquil, Nathalie, leloc'h, Francois, Hatab, Tarek, and Preciado, Izaskun

Abstract

Using the Bay of Biscay (BoB) as a case study, we conducted a transnational assessment of the mean trophic level (MTL, Ospar FW4) indicator at sub-regional level, over the last three decades. Our results confirm the apparent recovery of BoB’s bentho-demersal system, as shown by trends in the MTL indicator based on survey data. However, they also point at a concomitant “fishing through” process where the apparent stability revealed by the MTL indicator based on landed catch data may be masking the expansion of demersal fisheries to deeper waters, and an over-exploitation of resources (particularly abundant pelagic species). Moreover, they show how the combined examination of independent surveys and fishery landings allows the identification of ecological trends in ecosystem studies. In addition, our results confirm that analysing MTL at various threshold levels helps discerning the causality of trends in this indicator, especially if analyses for pelagic and demersal species are run independently. Further studies, at smaller (i.e. local) spatial scales, need to be conducted to ascertain our results and suggest appropriate management strategies aimed at regulating fisheries expansions in the area.

Published
2019

27. Proposed approaches for indicator integration. ECAPRHA Deliverable Wp 4.1

Author

Elliot, Sam, Arroyo, N.L. (Nina Larissa), Safi, Georges, Ostle, C., Gerin, L., McQuatters-Gollop, A., González-Irusta, J.M. (José Manuel), Preciado, I. (Izaskun), López-López, L. (Lucía), Punzón, A. (Antonio), De-la-Torriente, A. (Ana), Serrano, A. (Alberto), and Otros

Subjects
fish, Centro Oceanográfico de Santander, conservation, Pesquerías, community composition
Published
2017

29. EcApRHA Action Plan for the further implementation of habitat and food web indicators and progressing integrated assessments in OSPAR (sub) regions

Author

Padegimas, Bernardas, Artigas, Luis Felipe, Arroyo, Nina Larissa, Aubert, Anaïs, Budria, Alexandre, E. Capuzzo, Corcoran, Emily, Elliott, Sophie, González-Irusta, José Manuel, Guerin, Laurent, Judd, Adrian, Kromkamp, Jacco C., McQuatters-Gollop, Abigail, Meakins, Bryony, Niquil, Nathalie, Ostle, Clare, Pesch, Roland, Preciado, Izaskun, Safi, Georges, Schmitt, Petra, Serrano, Alberto, R. Thorpe, Torriente, Ana, and Vina-Herbon, Cristina

Published
2017
Full Text
View/download PDF

30. Describing the Bay of Biscay's continental shelf food-web using an OSPAR common indicator: the Mean Trophic Level indicator

Author

Safi, Georges, Vouriot, Pauline, Arroyo, N.L. (Nina Larissa), Féral, J.P., Hattab, Tarek, Lamare, S., Mialet, B., Niquil, N. (Nathalie), Petit, L., Preciado, I. (Izaskun), Serre, S., and Le Loc'h, F.

Subjects
Centro Oceanográfico de Santander, food webs, Medio Marino, trophic level, Bay of Biscay, indicators
Abstract

The current development of biodiversity indicators adopted as common in the North East Atlantic (Under OSPAR Regional Sea Convention) is missing some elements necessary for their application as food-web indicators. The Mean Trophic Level (MTL) indicator is based on species biomass and their trophic level (TL). These metrics are commonly used in the food-web holistic approach of interactions in an ecosystem. Species TL, giving the position of an organism in the food web, is influenced by spatiotemporal variability and ontogeny of species. MTL is also shaped by the species biomasses and their data source (i.e. landings or survey data). The aim of the present study was to propose a methodology (1) considering a better regionalisation of the indicator (i.e. using local TL estimations and ecosystem survey data), (2) looking at the MTL sensitivity regarding ecosystem species and compartments and (3) discussing the food web approach of the indicator. Different scenarios were thus tested on MTL indicator with EVHOE survey data (i) using various data sources of TL and (ii) applying several cut-offs to focus on different compartments in the ecosystem. Species influence on each scenario was also investigated. Two species were found to be highly influencing the MTL indicator trend. Capros aper, a low TL species catching the bottom up effect in the food-web, was strongly acting on MTL when considering all species in the ecosystem. Meanwhile, Merluccius merluccius was driving the indicator when low trophic level species were cut-off. This high predator reflected more the top down effect on the ecosystem. This work concluded the need to assess the MTL indicator using three TL cut-offs (TL= 2, 3.25 and 4) to capture a holistic view of changes in the ecosystem. Furthermore, scientific surveys and local estimations of TL are crucial in order to reduce uncertainty around the MTL estimation.

Published
2016

32. Stock structure of the English Channel common cuttlefish Sepia officinalis (Linnaeus, 1758) during the reproduction period

Author

Gras, Michael, Safi, Georges, Lebredonchel, Hugo, Quinquis, Jerome, Foucher, Eric, Koueta, Noussithe, Robin, Jean-paul, Gras, Michael, Safi, Georges, Lebredonchel, Hugo, Quinquis, Jerome, Foucher, Eric, Koueta, Noussithe, and Robin, Jean-paul

Abstract

Within the English Channel, the common cuttlefish Sepia officinalis is a semelparous species for which a 2-year life cycle was exclusively described in the 1980s. In the 1990s, new research indicated that whilst a 2-year life cycle was still evident for females and the large majority of males, a small proportion of males were actually maturing at only 1 year of age. Since 1980, the interest of French and UK fishers for this resource has increased and it is nowadays one of the most important demersal species of the area and is considered to be fully exploited. From the start of the 20th century, fishing effort and sea surface temperatures have increased in the English Channel and have probably impacted the life history traits of S. officinalis. A 2-year sampling programme was undertaken at French landing sites of the English Channel during the reproduction season in 2010 and 2011 to estimate if the proportion of 1-year-old mature animals has changed. Age determination was carried out by coupling polymodal decomposition and lipofuscin measurement. Size-at-maturity for each year and each sex was estimated by fitting a binomial error GLM. Results highlight that a variable percentage of males and females belonging to the first cohort are mature and that size-at-maturity was lower than that observed in the 1990s. Finally, different parameters, such as temperature and fishing pressure are explored to discuss changes in life history traits suggesting that cuttlefish could be an indicator of the temperature regime shift in the English Channel.

Published
2016
Full Text
View/download PDF

33. Etude de la variabilité spatio-temporelle des caractéristiques physiologiques des jeunes stades de vie de la seiche Sepia officinalis L. en Manche

Author

Safi, Georges

Subjects
English Channel, oeufs--incubation, ecophysiology, Seiche, protéases, Cuttelfish, eggs--incubation, enzymes digestives, recrutement (biologie), recruitment (Population biology), digestive enzymes, Manche (mer), proteinase, lysozyme, écophysiologie
Abstract

The common cuttlefish Sepia officinalis, is a major exploited marine resource in the English Channel. It has strong seasonal and interannual variations in recruitment. Mechanisms affecting the renewal of the stock by the arrival of new “recruits” and their number need to be better understood. Thus the study of the spatial and temporal variability of “pre-recruits” physiological characteristics was conducted in four spawning sites of the Channel [i.e. Agon Coutainville (FR), Baie de Seine (FR), Selsey (UK) and Torbay (UK)]. The studied parameters were the eggs quality and hatching rate then, the digestive and immune performance of juveniles in relation to local environmental conditions. English eggs have a delayed hatching time and higher hatching rate when compared to the French ones. Temperature and salinity are important in understanding these differences. The digestive performance of hatchlings varied according to the site. The study of immune enzyme activities showed local vulnerabilities of early stages which corresponded to episodes of high mortality. These mortalities are correlated with low protein content and low immune activities in eggs. These results underline how variability in the spatio-temporal characteristics of the early life stages of cuttlefish can influence the contribution of spawning sites to S. officinalis stock in the English Channel., La seiche commune Sepia officinalis, est une des principales ressources marines exploitées en Manche. Elle présente de fortes variations saisonnières et interannuelles au recrutement. Les mécanismes affectant le renouvellement du stock par l’arrivée des nouvelles « recrues » et leur effectif doivent être mieux élucidés. Ainsi l’étude de la variabilité spatio-temporelle des caractéristiques physiologiques des stades « pré-recrues » a été menée dans quatre sites de ponte en Manche [i.e. Agon Coutainville (FR), Baie de Seine (FR), Selsey (UK) et Torbay (UK)]. Les paramètres étudiés étaient la qualité des oeufs et des taux d’éclosion puis, les performances digestives et immunitaires des juvéniles, en relation avec les conditions environnementales locales. Les oeufs des sites anglais ont des éclosions plus tardives et un taux d’éclosion supérieur comparé à ceux des sites français. La température et la salinité, sont importantes dans la compréhension de ces différences. Les performances digestives des animaux à l’éclosion varient en fonction des sites. L’étude des activités enzymatiques immunitaires a montré des vulnérabilités locales des jeunes stades qui induisent des épisodes de forte mortalité. Ces mortalités sont corrélées à des oeufs montrant un faible contenu protéique et ayant de faibles activités immunitaires. Ces résultats indiquent des variabilités spatio-temporelles dans les caractéristiques des jeunes stades de la seiche qui influencent la contribution des différents sites au stock de S. officinalis en Manche.

Published
2013

34. Digestive enzyme ratios are good indicators of hatchling yolk reserve and digestive gland maturation in early life stages of cuttlefish Sepia officinalis L.: application of these new tools in ecology and aquaculture.

Author

Safi, Georges, Martinez, A. S., Le Pabic, C., Le Bihan, E., Robin, J. P., and Koueta, N.

Subjects
*CUTTLEFISH, *EGG yolk, *DIGESTIVE organs, *ECOPHYSIOLOGY, *PHOSPHATASES
Abstract

In Sepia officinalis (Linnaeus, 1758), the digestive gland matures during the first month post-hatching, while a shift from intracellular acid to extracellular alkaline digestion occurs. The purpose of this study was to investigate the possibility of using enzymatic ratios for the description of digestive system maturation in early life stages of S. officinalis. Second, it is intended to apply these new tools as eco-physiological indicators for understanding the impact of cuttlefish eggs' life history from different spawning sites of the English Channel on digestive performance of juveniles. An experimental rearing was performed over 35 days after hatching (DAH) on juveniles from wild collected eggs in 2010 and 2011. Four digestive enzyme activities and their ratios [i.e., trypsin, cathepsin, acid (ACP), and alkaline (ALP) phosphatase, ALP/ACP, and trypsin/cathepsin] were studied along with histological features (e.g., internal yolk surface and digestive gland development). The two enzyme ratios were good indicators of digestive system maturation allowing the study of the digestive gland's development. They were highly correlated to juveniles' weight increase and histological features of the gland in early DAH. These ratios described more accurately the shift occurring between the intracellular acid and the extracellular alkaline modes of digestion in S. officinalis and were more specific than separated enzyme activities. Their application as eco-physiological tools revealed that enzyme ratios reflected yolk content and digestive gland development in new hatching juveniles. Finally, ALP/ACP ratio was shown to be a powerful tool to describe growth performance of S. officinalis which is useful for aquaculture optimization. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

37. Stock structure of the English Channel common cuttlefish Sepia officinalis (Linnaeus, 1758) during the reproduction period.

Author

GRAS, MICHALË, SAFI, GEORGES, LEBREDONCHEL, HUGO, QUINQUIS, JÉRÔME, FOUCHER, ÉRIC, KOUETA, NOUSSITHÉ, and ROBIN, JEAN-PAUL

Abstract

Within the English Channel, the common cuttlefish Sepia officinalis is a semelparous species for which a 2-year life cycle was exclusively described in the 1980s. In the 1990s, new research indicated that whilst a 2-year life cycle was still evident for females and the large majority of males, a small proportion of males were actually maturing at only 1 year of age. Since 1980, the interest of French and UK fishers for this resource has increased and it is nowadays one of the most important demersal species of the area and is considered to be fully exploited. From the start of the 20th century, fishing effort and sea surface temperatures have increased in the English Channel and have probably impacted the life history traits of S. officinalis. A 2-year sampling programme was undertaken at French landing sites of the English Channel during the reproduction season in 2010 and 2011 to estimate if the proportion of 1-year-old mature animals has changed. Age determination was carried out by coupling polymodal decomposition and lipofuscin measurement. Size-at-maturity for each year and each sex was estimated by fitting a binomial error GLM. Results highlight that a variable percentage of males and females belonging to the first cohort are mature and that size-at-maturity was lower than that observed in the 1990s. Finally, different parameters, such as temperature and fishing pressure are explored to discuss changes in life history traits suggesting that cuttlefish could be an indicator of the temperature regime shift in the English Channel. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

38. Recommandations for the quantitative assessment of metal inputs in the marine environment from the galvanic anodes of offshore renewable energy structures

Author

Michelet, Nicolas, Julian, Nais, Duarte, Rui, Burgeot, Thierry, Amouroux, Isabelle, Dallet, Melissa, Caplat Christelle, Jean-Louis Gonzalez, Pierre GARREAU, Aragon Emmanuel, Perrin Francois-Xavier, and Safi, Georges

Abstract

The fast-growing offshore wind industry represents a potential new anthropogenic pressure for the marine environment. Despite the fact that it is considered as a green/clean energy source, the large-scale deployment of these devices could induce some environmental impacts that need to be studied. Understanding these impacts is in line with the Marine Strategy Framework Directive (MSFD) (European Commission, 2008) of the European Union which targets good environmental status for the marine environment. The development of offshore renewable energies (ORE), in particular floating and fixed offshore wind structures in France, gives rise to new and more precise questioning from the French public authorities and civil society. In particular, a lot of questions have emerged in relation to the use of Galvanic Anode Cathodic Protection (GACP) systems and about the release of heavy metals associated with their functioning. These anodes are composed of different metals which are more reducing than the metal to be protected. The anodes are generally made with magnesium, aluminium or zinc. In offshore industries such as offshore wind turbines or oil & gas platforms, the anodes used are mainly composed of an aluminium alloy which contains zinc and other trace metals. Their installation in fishing zones is a source of major concern and this affects several offshore wind farm projects (such as Île d’Yeu and Noirmoutier). This growing concern from public authorities and civil society has even led to galvanic anodes being abandoned in certain projects in order to overcome this problem. For example, the chosen solution for the jacket foundations of the Dieppe Le Tréport project is to implement cathodic protection by impressed current (ICCP) with titanium anodes). GACP has been replaced by ICCP in several projects although no scientific study has been conducted to prove the environmental impact of GACP in the ORE context, and no scientific study has proven that ICCP has no environmental impact. In this context, a chemical risk assessment process has been conducted through a 1-year collaborative R&D project called ANODE in order to determine whether the chemicals released from GACP may represent a risk for the marine environment. Such chemical risk assessments are based on the comparison of the predicted or measured concentration (PEC - Predicted Environmental Concentration) for a contaminant with its hazard data (PNEC - Predicted No Effect Concentration) for all environmental compartments (water column, sediment and biota for the marine environment). This is an iterative process the first step of which is based on a worst-case approach in order to ensure a high protective level for the marine environment. Through the ANODE project, the risk assessment was conducted on the water column only. A hydrodynamic model was developed as a first approach for the prediction of the dispersion of these metals in the water column. From this numerical model, a predicted concentration PEC was determined to be compared with existing PNECseawater. Three sites were studied representing different hydrodynamic conditions directly influencing the metal dispersion and different technologies (i.e. fixed and floating offshore wind turbines). The project objectives were as follows: To perform a literature review of the different cathodic protection systems used in the offshore industry with a focus on GACP and current knowledge of its potential impact on the marine environment. To draw up an overview of the data required for the numerical simulation and the availability of these data in the study areas. To model the hydrodynamics of the selected areas, i.e. Courseulles-sur-Mer in the English Channel, Leucate in the Mediterranean and Groix & Belle-Île off the Atlantic coast, and simulate the metal releases and the evolution over time of their concentrations in the various case studies. To conduct a risk assessment by comparing the results obtained using the model with existing toxicity thresholds (in the water column). Following these objectives, this report summarises the main results of the project and outlines a number of recommendations. This report is constructed as follows: The first section provides a summary of the principal results of the project; The second part presents the methodological recommendations for the environmental risk assessment; The third part lists methodological recommendations for future ORE installations and their associated impact studies.

39. Recommandations pour une approche écosystémique des aires d’implantation d’énergies marines renouvelables. Cas d’étude du parc éolien offshore de Courseulles-sur-mer

Author

Araignous Emma, Beaugrand Gregory, Ben Rais Lasram Frida, Pierre Bourdaud, Champagnat, Juliette, Dauvin Jean-Claude, Grangeré Karine, Ghassen Halouani, Haraldsson Matilda, Hattab, Tarek, Le Loch, Francois, Leroy Boris, Lejart, Morgane, Niquil Nathalie, Nogues Quintin, P, Pagot J., Raoux Aurore, Safi, Georges, and Maria Ching Villanueva

Abstract

Les études d’impact environnemental menées en amont des projets éoliens offshores considèrent chaque compartiment de manière individuelle, et non pas l’écosystème dans son ensemble. La compréhension des liens trophiques et l’appréhension de l’écosystème de manière holistique est pourtant un enjeu important rapporté par les politiques publiques telles que la Directive Cadre Stratégie pour le Milieu Marin (Directive 2008/56/EC). Le projet collaboratif TROPHIK (ANR-10-IEED-0006-12) pose les bases d’une approche écosystémique des Energies Marines Renouvelables (EMR) destinée à permettre une démarche holistique et intégrée avant installation de parcs éoliens en mer. Cette approche s’appuie sur un cas d’étude français, le site du futur parc éolien au large de Courseulles-sur-mer développé par le consortium « Parc éolien en mer du Calvados ». Le réseau trophique est considéré dans sa globalité, du plancton aux prédateurs supérieurs (oiseaux et mammifères marins), de la baie de Seine jusqu’à la zone économique exclusive française. Différentes approches de modélisations abordant plusieurs dimensions ont été utilisées et/ou développées afin d’appréhender les effets directs et indirects des EMR de manière holistique. Elles permettent également l’intégration de ces dispositifs de récupération d’énergie dans un contexte plus global de cumul d’impacts et au sein d’un réseau socio-écologique. La première partie de cet ouvrage est consacrée à des fiches récapitulatives présentant l’objectif, la méthode et les résultats principaux du projet ainsi que les personnes impliquées dans la valorisation scientifique qui en a découlé. Dans l’optique de la mise en place d’une approche écosystémique des EMR, la seconde partie recense les recommandations et perspectives issues de ces travaux afin de contribuer à l’étude et à l’amélioration de la compréhension des effets liés à l’intégration de nouvelles infrastructures dans les écosystèmes marins.

Catalog

Books, media, physical & digital resources
See catalog results