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| Registros recuperados: 31 | |
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| Gros, Philippe. |
| Fisheries and aquaculture provide at least 15% of their animal protein diet to 4.3 billion persons. The rise of aquaculture dates back to the end of the 1980s, when fisheries’ production rate was beginning to decline, sounding the end of its post World War II growth phase. The volume of official landings culminated 25 years ago, without outlook for any further increase. About 60% of fish stocks are currently exploited at the maximum sustainable yield (MSY) level, most of the other ones being overexploited because of the chronic overcapacity of the fleets and of poorly regulated access to fishing. The ecosystem approach to fisheries (EAF) emerged as paradigm shift in the 1990s, underpinning the renewal of management objectives and governance along with... |
| Tipo: Text |
Palavras-chave: Common fishery policy; Ecological footprint; Ecosystem approach to fisheries; Fisheries; Global change; Good ecological status. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00183/29414/27775.pdf |
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| Gros, Philippe. |
| The objective of this report is to characterize the evolution of the pelagie coastal ecosystem (studied by sampling hydrobiological parameters, phytoplankton and zooplankton) off the Gravelines' nuclear power plant (french coast of the North Sea). The sampling program (contractually defined by the Centre National pour l'Exploitation des Océans and Electricité de France) is composed of several successive phases. The results obtained for the first three of them (september 1974 - december 1975 ; august 1976 - july 1977 ; january 1978- june 1979) are presented in this report, with special emphasis on the third one realized just before the power plant's activity started (march 1980). It is shown that, from 1974 to 1979, some subsets of the ecosystem (such as... |
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| Ano: 1981 |
URL: http://archimer.ifremer.fr/doc/00101/21213/18828.pdf |
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| Gros, Philippe. |
| Linear regression modelling is one of the most widely used statistical tools: usual applications of this "core technique" encompass description and analysis of experimental data, interpolation, help in recognizing causal relationships, and forecasting. It is thus necessary for the practicioner to obtain an understanding of the basic principles necessary to apply regression methods in a variety of settings. Accordingly, the first two chapters provide the standard results for the simple linear regression (only one controlled variable, or regressor). Since the emphasis is on practical applications, theoretical results are stated without proof, and the major guidelines are building models, assessing fit and reliability, and drawing conclusions. Chapter 1... |
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| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00013/12405/9191.pdf |
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| Guarini, Jean-marc; Blanchard, Gf; Gros, Philippe; Gouleau, Dominique; Bacher, Cedric. |
| In the present paper, we list and document the relevant behavioral and physiological processes controlling primary productivity of epipelic microalgae on intertidal mudflats in order to develop a simplified model. We first propose, in an attempt to characterize the 'photosynthetically active biomass' of the epipelic community, a new approach to describe the photic environment at the sediment surface, by substituting a discrete a-layer model in place of continuous vertical light distribution. This concept thus allows us to build a functional representation of the distribution of the photosynthetically active biomass in the sediment and, by then integrating the light and temperature forcing of the latter biomass, to predict the dynamics of the whole epipelic... |
| Tipo: Text |
Palavras-chave: Microphytobenthos; Intertidal mudflat; Primary production; Dynamic model; Migratory rhythm; Ecophysiological response. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00000/10540/7601.pdf |
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| Gros, Philippe; Hamon, Dominique. |
| The aim of this report is to provide biomass estimates (AFDW, g.m-2 ) of the four main components of the benthic food web in the southern part of the Bay of St-Brieuc: suspension-feeders, deposit-feeders, herbivores and carnivores. Patterns in the environmental data (i.e., sedimentary characters) are first analysed, and then related to the spatial distribution of communities ; both approaches use classical ordination techniques (PCA, correspondence analysis). A second typology, based on a review of published litterature concerning coastal macrozoobenthos feeding, ascribes each taxonomic unit to a trophic group. Finally, quantitative results are thus given per biota ; suspension-feeders appear to dominate (in terms of biomass) most of fine-sand habitats of... |
| Tipo: Text |
Palavras-chave: Zoobenthos; Réseau trophique; Analyses multivariables; Manche ouest; Zoobenthos; Food web; Multivariate analysis; Western Channel. |
| Ano: 1988 |
URL: http://archimer.ifremer.fr/doc/00107/21794/19371.pdf |
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| Guarini, Jean-marc; Blanchard, Gerard; Bacher, Cedric; Gros, Philippe; Riera, Pascal; Richard, Pierre; Gouleau, Dominique; Galois, Robert; Prou, Jean; Sauriau, Pierre-guy. |
| Microphytobenthos plays an important role as primary producer in shallow embayments subject to a tidal regime. The present paper aims to characterize the spatial patterns of sedimentary chlorophyll a (chl a) biomass in 2 seasons in the wide intertidal mudflats of the Marennes-Oleron Bay (France); furthermore, it provides estimates of total microphytobenthic biomass. Accordingly, a systematic sampling scheme was performed in June 1995 and in January 1996. On average, biomass was higher in June (ca 120 mg chl a m-2) than in January (ca 85 mg chl a m-2). Moreover, the geostatistical analysis revealed that spatial similarities were propagated over larger distances in June (6 km) than in January (2.2 km). In order to account for this result , we suggest that... |
| Tipo: Text |
Palavras-chave: Marennes Oleron; Intertidal mudflat; Geostatistics; Spatial distribution; Chrlorophyll a; Microphytobenthos. |
| Ano: 1998 |
URL: https://archimer.ifremer.fr/doc/1998/publication-3820.pdf |
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| Chardy, Pierre; Gros, Philippe; Mercier, Herle; Monbet, Yves. |
| A steady-state energy flow model is proposed for the benthic fine sand community of the Bay of Saint-Brieuc. The main objective is to assess the relative importance of benthic processes associated with the carbon cycle in an eutrophicated bay. Available data include biomass estimates of the major trophic groups and measurements of the most critical fluxes : particulate organic carbon sedimentation, community respiration, microbial production. A balanced annual carbon budget is estimated using an inverse method, particularly appropriate in food web research where the number of unknowns is far higher than the number of independent observations. The method offers the possibility of taking dynamical constraints into account, by introducing global flow... |
| Tipo: Text |
Palavras-chave: CARBON CYCLE; BENTHIC COMMUNITY; FINE SANDS; SUBTIDAL AREA; INVERSE METHOD. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21131/18751.pdf |
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| De Verdelhan, Claude; Gros, Philippe; Catanzano, Joseph. |
| (i) La pertinence du thème est attestée par la richesse de la littérature internationale qui lui est consacrée. 11 convient au demeurant de noter la présence de publications de l'IFREMER dans ce même domaine. Les principaux acquis procèdent généralement d'approches descriptives, permettant de disposer à ce jour d'un inventaire quasi exhaustif des différents outils de gestion classiquement mis en oeuvre. D'ores et déjà il apparaît que la question de la transférabilité de mesures de gestion (e.g QIT, Licence, PME...) soulève plusieurs interrogations: cohérence juridique, acceptabilité, contrôle, coûts, efficience... Mais surtout, poser l'étude de la régulation en termes d'analyse du comportement d'un système élargit le champ des investigations au delà du... |
| Tipo: Text |
Palavras-chave: SEM. |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/1992/rapport-4235.pdf |
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| Gros, Philippe; Hamon, Dominique. |
| The aim of this report is to provide total biomass estimates of the blue mussel (Mytilus edulis, M. galloprovincialis) livestock harvested on mussel beds, and of the cockle Cerastoderma edule in the Bay of Saint-Brieuc. The sampling scheme for reared mussels combines stratification and three-stage sampling. The biomass of mussels, estimated twice in a year, remains close to 3 500 metric tons of wet weight (coefficient of variation : 10 to 14 %). A nonrandom, systematic sampling was performed to estimate the total biomass of cockles, the data being processed according to the geostatistical methods the biomass of the stock exhibits seasonal variability : 4 800 tons (CV : 15 %) at the end of summer, vs. 3 700 tons (CV: 17 %) at the beginning of spring. The... |
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| Ano: 1989 |
URL: http://archimer.ifremer.fr/doc/00040/15152/12489.pdf |
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| Guarini, Jean-marc; Blanchard, Gerard F.; Gros, Philippe; Harrison, S.j.. |
| The mud surface temperature (MST) of an intertidal mudflat in Marennes-Oléron Bay (France) and the biomass-specific photosynthetic capacity (PBmax) of benthic microalgae were modelled to investigate their spatio-temporal dynamics. Simulations were performed over 2 different periods during and after the microphytobenthos spring bloom (April and June, respectively) and under 2 different tidal conditions (spring and neap tides). The deterministic MST model is based on thermodynamic processes. Comparison at different periods between measured data series and simulations clearly establishes the reliability of the model, thus allowing extrapolations over time and space. The spatio-temporal dynamics of MST is primarily controlled by the immersion-emersion... |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00013/12398/9184.pdf |
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| Bertrand, Arnaud; Josse, Erwan; Bach, Pascal; Gros, Philippe; Dagorn, Laurent. |
| We studied relationships between tropical tunas (albacore (Thunnus alalunga), bigeye (Thunnus obesus), and yellowfin (Thunnus albacares)) and their biotic and abiotic environments through simultaneous acoustic observations of tunas and their prey, experimental longline catch, and oceanographic data in French Polynesia. Vertical habitat limits were estimated based on temperature and dissolved oxygen at capture data. We then studied tuna-micronekton relationships to better understand how tuna occupy the pelagic space, At a regional scale, tunas were more abundant in areas rich in prey with favourable hydrological conditions. Inside such areas, at the scale of a longline set, however, the longline catches were maximal only when prey were not distributed in... |
| Tipo: Text |
Palavras-chave: Hydrological; Acoustic observations; Tunas. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/publication-733.pdf |
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| Blanchard, Gerard F.; Guarini, Jean-marc; Richard, Pierre; Gros, Philippe; Mornet, Francoise. |
| A mathematical expression is proposed to describe the relationship between the photosynthetic capacity (Pmax) of natural assemblages of motile benthic diatoms and temperature. Experiments were performed in 2 different seasons to document the response of Pmax to a rapid increase in temperature (3*C h-1). In both cases, there was a progressive increase in Pmax up to an optimum temperature (Topt), beyond which Pmax declined rapidly. Topt did not change from September to December 1995, but the maximum photosynthetic capacity (PMAX, i.e. Pmax at Topt) was twice as high in September as in December. |
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| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00013/12397/9183.pdf |
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| Gros, Philippe; Biseau, Alain; Fromentin, Jean-marc; Thebaud, Olivier. |
| The report is focused on the research priorities pertaining to the implementation of the ‘maximum sustainable yield’ (MSY) and of the ‘ecosystem approach to fisheries’ (EAF). The MSY is first examined, taking account of its relevance as a management objective, of its link with maximum economic yield (MEY), and of its close relationship with ecosystem productivity and fishing capacity. Related research priorities are identified. In the second part, emphasis is put on EAF, a very challenge for fishery scientists. The extension of fisheries science towards an ecosystem dimension (including human activities) and the integration of uncertainty have opened up large fields of research. Priorities are presented by domain. Five principal areas of knowledge and... |
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| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/00013/12408/9194.pdf |
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| Gros, Philippe. |
| Gros, Ph. (2011). Marine Ecosystems, Chapter 5 in: Current knowledge of impacts of climate change on biodiversity from Metropolitan France – A literature review. Coord. N. Massu & G. Landmann (Ecofor), MEDDTL, 179 pp. This chapter aims at providing an overview of the current knowledge of impacts of climate change on biodiversity in the marine eco-regions from Metropolitan France (i.e. in the North Sea, English Channel, Celtic Sea, Bay of Biscay and north-western Mediterranean Sea). The major physical (heat budget, circulation) and chemical (acidification) changes in waters of the north-eastern Atlantic and of the western Mediterranean Sea are summarized. Based on results from multidecadal time series analysis and from ongoing research work, examples... |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00043/15394/12749.pdf |
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| Registros recuperados: 31 | |
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