Consulta: subjectFacets:"Loire"
Registros recuperados: 16
Data/hora: 01/06/2024 03:44:14

Etude intégrée du secteur Loire Vilaine : synthèse des connaissances, analyse des problématiques
Provedor de dados: 5
Autores: Baudrier, Jérôme.
The coastal area located between Quiberon and Noirmoutier is influenced by dilution plumes of the Loire and Vilaine rivers. Dysfunctions linked with a growing eutrophication of the environment have been observed over the last decades. Important imbalances such as massive deaths of the fauna in open embayments and more and more appearances of red tides give the area a unique character. Other environ mental problems are likely to disrupt human activites in the near future (bays silting up, quality of coastal water worsening, overfishing ...). This is why there is a real need to gather information on the subject. This will make it possible to identify problems and gaps in the area. Beside presenting pieces of information, the study offers various reflection...
Tipo: Text
Palavras-chave: Loire; Vilaine; Panaches de dilution; Eutrophisation; Déséquilibres; Écosystème.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/00016/12702/9624.pdf

Suivi 2014 des captures d'anguilles pour la DCF : analyse des otolithes
Provedor de dados: 5
Autores: Elleboode, Romain; Oudard, Clemence; Bellamy, Elise; Penil, Caroline; Mahe, Kelig.
Ce rapport synthétise l'analyse des otolithes d'anguilles prélevés en 2014 dans le cadre du suivi des captures de cette espèce inscrite à la DCF (Data Collection Framework règlement CE n°199/2008 du conseil du 25 février 2008). 212 anguilles ont été prélevées de septembre à décembre 2014 dans le lac de Grand Lieu (n=49), la Loire fluviale (n=51), la Dordogne (n=59) et la Garonne (n=53). La relation entre la longueur totale (Lt) et le poids total (W) des anguilles prélevées en 2014 dans toute la France est du type W = 4.10-4.Lt3,41. Ainsi, les anguilles présentent une allométrie majorante (b=3,41) c’est-à-dire que le poids croit plus vite que la longueur. L'institut IFREMER à travers le pôle national de Sclérochronologie à Boulogne-sur-mer a préparé et...
Tipo: Text
Palavras-chave: Anguille; Otolithe; Age; Dordogne; Loire; Garonne; Lac de Grand Lieu.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00310/42082/41385.pdf

Suivi 2011 des captures d'anguilles pour la DCF : analyse des otolithes
Provedor de dados: 5
Autores: Mahe, Kelig; Penil, Caroline; Sevin, Karine.
Ce rapport synthétise l'analyse des otolithes d'anguilles prélevés en 2011 dans le cadre du suivi des captures de cette espèce inscrite à la DCF (Data Collection Framework règlement CE n°199/2008 du conseil du 25 février 2008). 140 anguilles ont été prélevées entre fin juillet et fin octobre 2011 dans la Loire, la Dordogne et la Gironde. La relation entre la longueur totale (Lt) et le poids total (Wt) des anguilles prélevées en 2011 dans toute la France (Loire, Garonne et Dordogne) est du type Wt = 5.10-7.Lt3,21. Ainsi, les anguilles présentent une allométrie majorante (b=3.21) c’est-à-dire que le poids croit plus vite que la longueur. L'institut IFREMER à travers le pôle national de Sclérochronologie à Boulogne-sur-mer a préparé et interprété les...
Tipo: Text
Palavras-chave: Anguille; Otolithe; Age; Dordogne; Garonne; Loire.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00310/42080/41383.pdf

Approche quantitative de la fonction de nourricerie jouée par les systèmes vasières-estuaires
Provedor de dados: 5
Autores: Parlier, Emmanuel.
Coastal fish populations settle more or less frequently, at various stages, estuarine systems. Tidal marshes are one of the components of these mosaics of habitats. The first part of this work describes fish assemblages through the utilisation of these systems by fishes analysed in order to propose a revised functional classification of ecological guilds. T h i s new classification is used to compare fish communities of four estuarine systems in the western coast of France: the Mont Saint- Michel Bay, the Saint-Brieuc Bay, the Loire estuary and the Aiguillon Bay. The second part aims at characterizing the nursery function as defined by Beck et al. (2001). Acombinative approach based on gut content analysis, and stable isotope analysis shows that Yo Y s e a...
Tipo: Text
Palavras-chave: Isotope ratio; Otolith; Saltmarsh; Nursery; Mont Saint Michel Bay; Saint Brieuc Bay; Aiguillon Bay; Seine estuary; Loire estuary; NEA; Dicentrarchus labrax; Fish communities; Rapports isotopiques; Otolithe; Marais salés; Nourricerie; Baie du Mont Saint Michel; Baie de Saint Brieuc; Baie de l'Aiguillon; Seine; Loire; ANE; Dicentrarchus labrax; Peuplement de poissons.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/these-4601.pdf

Modélisation mathématique de l'oxygène dissous dans l'estuaire de la Loire. Première phase
Provedor de dados: 5
Autores: Thouvenin, Benedicte; Romana, Louis-alexandre.
Depuis plusieurs années, on observe en période post-estivale un très important déficit en oxygène dissous dans l'estuaire de la Loire, accompagné par une mortalité élevée de certaines espèces halieutiques migratrices. L'origine de cette anoxie est imputée au stock de matière organique particulaire biodégradable qui est piégée dans la zone de turbidité maximale. A la demande de l'Association pour la Protection de l'Environnement de l'Estuaire de la Loire, un modèle mathématique a été mis en place pour décrire les mécanismes hydrodynamiques et hydrosédimenraires dans l'estuaire, ainsi que l'évolution de l'oxygène dissous et la dégradation de la matière organique. Dans une première phase, ce modèle reproduit l'évolution longitudinale et temporelle de...
Tipo: Text
Palavras-chave: Modèle mathématique; Estuaire; Loire; Oxygène dissous; Matière organique.
Ano: 1992
URL: http://archimer.ifremer.fr/doc/00439/55039/56471.pdf

Les pêches professionnelles dans les estuaires de la Loire et de l'Adour
Provedor de dados: 5
Autores: Guerault, Daniel; Desaunay, Yves; Beillois, Pierre; Prouzet, Patrick; Martinet, Jean-pierre; Cuende, François - Xavier.
The exploitation of amphihaline species by marine and freshwater commercial fishermen in the Loire estuary in 1989, and by marine commercial fishermen in the Adour estuary from 1985-1991 is described in this study. This fishery employs 320 fishermen and represents a commercial value of 38 million FF. This is mainly due to the exploitation of glass eel, especially in the Loire River, the landings of which have decreased alarmingly. In the Adour River, the diversity of the exploited species and the total commercial value of drift gillnet catches - on the average 43% - in this fishery are high. The landings of migratory salmonid species are high and they may attain 25% of the total commercial value. This study emphasizes the uniqueness, the socio-economic...
Tipo: Text
Palavras-chave: France; Loire; Adour; Atlantique; Socio économie; Biologie; Pêcherie estuarienne; Espèce amphihaline; France; Adour River; Loire River; Ocean; Atlantic; Socio economy; Biology; Estuarine fisherie; Amphihaline specie.
Ano: 1994
URL: https://archimer.ifremer.fr/doc/1994/rapport-1452.pdf

Transformation de la phase solide à travers l’estuaire de la Loire en relation avec son environnement chimique et biologique
Provedor de dados: 5
Autores: Thibault De Chanvalon, Aubin.
Before reaching the ocean, riverine particles from the Loire watershed undergo important chemical transformations in the estuary. This study aims to identify and characterize main processes involving iron (and to a lesser extent Al, Mn, PO4 3- and rare earths elements). Suspended particulate matter data show that 15% of their iron is lost through the estuary. Reductive iron dissolution during deposition periods is likely to explain most of this loss. However, estuarine sediments are characterized by high spatial heterogeneity due to macrofaunal activities. To overcome this difficulty, new methodologies of high resolution and two-dimensional analyses and calculation of pore water, sediment and benthic meiofauna were developed. These developments enable to...
Tipo: Text
Palavras-chave: Estuaire; Fer; Phosphore; Nitrate; Foraminifère benthique; Diagenèse précoce; Loire; Bioturbation; Estuary; Iron; Phosphorus; Nitrate; Benthic foraminifera; Precocious diagenesis; Loire; Bioturbation.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00498/60932/64325.pdf

Evaluation de l’état écologique des masses d’eau de transition dans le cadre de la DCE. Etude de la pertinence du suivi des peuplements du microphytobenthos estuarien
Provedor de dados: 5
Autores: Ribeiro, Lourenço; Le Bris, Anthony; Hernandez Farinas, Tania; Buchet, Remi; Dutertre, Mickaël; Metzger, Edouard; Rosa, Philippe; Gernez, Pierre; Lerouxel, Astrid; Barille, Laurent.
In order to establish the ecological status of water bodies, the European Water Framework Directive (WFD) is based on the evaluation of a number of biological quality elements, as well as physical parameters supporting the biology. In estuaries, phytoplankton monitoring was not considered relevant because of the high turbidity characterizing the large metropolitan estuaries and the French overseas departments (Guyana). In this work, we considered the possibility of using microphytobenthos (MPB) as a biological indicator of the ecological status of estuaries. This activity report summarizes the actions undertaken in 2017 under an AFB / Université de Nantes convention, which is structured around two main axes: the first axis is based on the analysis of the...
Tipo: Text
Palavras-chave: DCE; Diatomées benthiques; Diversité; Estuaires; Facteurs naturels; Gradient de perturbation; Loire; Bio-indication; Microphytobenthos; Pressions anthropiques; Télédétection.; Anthropogenic pressures; Benthic diatoms; Bio-indication; Diversity; Estuary; Loire; Microphytobenthos; Natural factors; Perturbation gradient; Remote sensing; WFD.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00446/55725/57376.pdf

Les prises accessoires de la pêcherie de civelles (Anguilla anguilla) dans l'estuaire de la Loire en 1987
Provedor de dados: 5
Autores: Guerault, Daniel; Desaunay, Yves; Bellois, Pierre; Grellier, Patrick; Robin, Jean-paul; Robineau, Brigitte.
A survey of the glass-eel fishery in the Loire estuary in 1987 (265 boats, 117 tons gasseel, 13733 fishing trips) showed that 16 fishery species constitute the by-catch (49,3 million individuals, mainly juveniles, among which 98 % consist in flounder, sprat and brown shrimp). The analysis of catches in space and time leads to proposaIs for Iimiting the impact during the last fishing weeks. Taking into account the naturai mortality rates of the concerned juveniles, an attempt is made to estimate the actuai impact of the glasseel fishery, after a delay. Only 10 % of the caught brown shrimps wouid have been recruited in the summer shrimp fishery. Up to 85,5 to 97,6 % of juvenile fishes would have disappeared during the following year by natural mortality.
Tipo: Text
Palavras-chave: Anguille; Pêcherie; Prises accessoires; Estuaire; Loire; Eel; Fishery; By catch; Estuary; Loire.
Ano: 1989
URL: http://archimer.ifremer.fr/doc/00120/23102/20951.pdf

Les risques conchylicoles en Baie de Quiberon. Troisième partie : le risque d’hypoxie pour l’huître creuse Crassostrea gigas. Rapport final du projet Risco 2010-2013
Provedor de dados: 5
Autores: Stanisiere, Jean-yves; Mazurie, Joseph; Bouget, Jean-francois; Langlade, Aime; Gabellec, Raoul; Retho, Michael; Quinsat, Kevin; Leclerc, Emilie; Cugier, Philippe; Dussauze, Morgan; Menesguen, Alain; Dumas, Franck; Gohin, Francis; Augustin, Jean-marie; Ehrhold, Axel; Sinquin, Jean-marc; Goubert, Evelyne; Dreano, Alain.
The project “Risco”, supported by the “Pôle Mer” and funded by the Regional Council of Brittany, deals with specific risks of mortality of oysters, Crassostrea gigas, cultivated on the bottom, in a subtidal bay of South Brittany : the bay of Quiberon (56, France). Massive mortalities of oysters were reported in summer 2006 in this bay, exclusively located in the deep muddy area with a positive gradient eastward. A validated biogeochemical model was applied in order to simulate the dissolved oxygen over 2000-2006 : it revealed several episodes of hypoxia, more or less intense according to years, but with the same spatial distribution. This approach proved 2006 to be the most hypoxic year since 2000. The hypoxia was due to a rare conjunction of 3 factors :...
Tipo: Text
Palavras-chave: Baie Quiberon; Crassostrea gigas; Huître; Mortalité; Croissance; Hypoxie; Oxygène; Modèle; Upwelling; Loire; Vilaine; Quiberon; Crassostrea gigas; Oyster; Mortality; Growth; Hypoxia; Oxygen; Model; DEB; Upwelling; Loire; Vilaine.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00180/29131/27535.pdf

Bionomie benthique de l'estuaire de la Loire. I. Observations sur l'estran maritime de la mer a Cordemais.
Provedor de dados: 5
Autores: Marchand, Jocelyne.
This study was the first to be undertaken since 1901, since when natural and industrial changes had occurred to affect the habitat. Observations are reported here for the banks of the north and south shores, using certain points as reference. Features of the 2 shores are described, and an inventory given of the fauna of the banks. Hydrozoan Cnidaria, Bryozoans, Annelids, Molluscs, Crustacea and fish are listed with notes, and particular attention is given to the crabs found (Rhithropanopeus harrisii tridentatus). The monthly distribution of crab sizes and sexes is given, and the species of animals found in association with crabs is shown to vary according to the site studied. The percentage of female crabs found to be fertile each month was investigated,...
Tipo: Text
Palavras-chave: Crustacea and fish; Molluscs; Fauna; Habitat; Observation; Loire; Benthic bionomy.
Ano: 1972
URL: http://archimer.ifremer.fr/doc/1972/publication-2069.pdf

Température, Salinité, Vent, Courantologie des marges du Mor-Bras
Provedor de dados: 5
Autores: Kerdreux, Michel.
In the coastal zone between the estuaries of Loire R. and Vilaine R., IFREMER has made four moorings from february to march and from june to september. The speed and steering of currents are precised, and the temperature and salinity are given. The Direction of national météorologie furnished the date necessary to trace wind speed and steering.
Tipo: Text
Palavras-chave: Loire; Vilaine; Courant; Vent; Loire R.; Vilaine R; Current; Wind.
Ano: 1987
URL: http://archimer.ifremer.fr/doc/00081/19270/52489.pdf

Etude sanitaire de la partie nord-ouest de la zone 44.09 « Estuaire de la Loire » - groupe 3 (bivalves non fouisseurs)
Provedor de dados: 5
Autores: Rocq, Sophie.
Suite à la pérennisation de l’exploitation d’un gisement d’huîtres creuses classé en zone à exploitation occasionnelle (dite « zone à éclipse »), la Direction Départementale des Territoires et de la Mer (DDTM) de Loire-Atlantique a demandé la réalisation d’une étude sanitaire en vue du classement pérenne de ce gisement se trouvant dans la partie nordouest de la zone 44.09 « Estuaire de la Loire ». Une étude de dossier et une inspection du littoral ont été réalisées afin de recenser les principales sources de contamination microbiologique et d’évaluer leurs impacts sur la zone étudiée. Ce travail préalable a permis de définir l’étendue du gisement côtier dont la qualité microbiologique pouvait être représentée par le point de suivi déjà existant 070-P-081...
Tipo: Text
Palavras-chave: Escherichia coli; Étude sanitaire; Loire-Atlantique; Classement sanitaire; Contamination bactériologique des coquillages; Huîtres; Non fouisseurs; Estuaire de la Loire; Loire.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00635/74738/74798.pdf

Modulation of sea surface temperature warming in the Bay of Biscay by Loire and Gironde Rivers
Provedor de dados: 5
Autores: Costoya, X.; Fernandez-novoa, D.; Decastro, M.; Santos, F.; Lazure, Pascal; Gomez-gesteira, M.
The influence of Loire and Gironde River discharges over the sea surface temperature (SST) in the eastern Bay of Biscay (0.6º–36.6ºW, 44.2º–47.8ºW) was analyzed by means of two complementary databases (MODIS and OISST1/4). The area influenced by river plume showed a different SST when compared with the adjacent oceanic area for the months when the plume attains its highest extension (December, January, and February). Ocean was observed to warm at a rate of approximately 0.3ºC dec−1 while temperature at the area influenced by the rivers cooled at a rate of −0.15ºC dec−1 over the period 1982–2014. The mere presence of a freshwater layer is able to modulate the warming observed at adjacent ocean locations since the coastal area is isolated from the rest of...
Tipo: Text
Palavras-chave: Loire; Gironde; SST; River plume; Warming modulation.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00311/42172/41472.pdf

Analyse des tendances des séries temporelles de la concentration en azote minéral dissous dans les trois principaux estuaires de la façade Manche-Atlantique
Provedor de dados: 5
Autores: Gailhard, Isabelle.
Estuaries are areas which, from their structure, their fonctioning, and their localisation, are subject to significant contribution of nutrients. One of the objectif of the RNO, the French network for coastal water quality monitoring, is to assess the levels and trends of nutrient concentrations in estuaries. A linear model was used in order to describe and to explain the total dissolved nitrogen concentration evolution in the three most important estuaries on the Chanel-Atlantic front (Seine, Loire and Gironde). As a first step, the selection of a reliable data set was performed. Then total dissolved nitrogen evolution schemes in estuary environment were graphically studied, and allowed a resonable choice of covariables. The salinity played a major role...
Tipo: Text
Palavras-chave: Nutriments; Estuaire; Loire; Seine; Gironde; Schéma de dilution; Modèle linéaire; Tendance; Nutrients; Estuary; Seine; Loire; Gironde; Dilution schema; Linear mode1; Trend.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00079/19070/16665.pdf

Suivi de flotteurs dans la zone Loire Vilaine
Provedor de dados: 5
Autores: Kerdreux, Michel; Merceron, Michel; Le Hir, Pierre; Breton, Marguerite.
During one month in summer of 1985 the courses of ten drifters, dropped at the mouth of Loire and Vilaine Rivers, were monitored. Results show:  -the marked influence of wind on the movement of this region's bodies of water, -the possibility of an intrusion of the Loire's waters in Vilaine Bay, -the very likely absence of any influence of the Loire's waters in the bottom waters' anoxia that occurred in Vilaine Bay during the summer of 1982.
Tipo: Text
Palavras-chave: Anoxia; Vilaine; Currents; Drifters; Anoxie; Vilaine; Loire; Courants; Flotteurs.
Ano: 1986
URL: http://archimer.ifremer.fr/doc/1986/rapport-2653.pdf