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| Registros recuperados: 11 | |
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| Allain, Gwenhael; Petitgas, Pierre; Lazure, Pascal. |
| Variability in anchovy recruitment in Biscay is temptatively explained using variables from the stock and from the environment during the ichtyoplankton phase. Anchovy recruitment depends on many different processes : weight of adults and proportion of multiple spawners (age 2), river discharges, upwelling events at the coast and at the shelf break. Meteorological variables (wind, rain, tempe rature ) are forcing effects on the sea but they are not the effective processes that govern the production in the sea. So they do not relate directly to the survival of larvae and to recruitment. In Biscay, many different physical processes are active and used by anchovy which spawns in different physical systems (river plumes, open ocean enrichment systems).... |
| Tipo: Text |
Palavras-chave: Bio-physical coupling; Recruitment; Anchovy; Hdrodynamics; Step by step regression. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00391/50190/50814.pdf |
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| Bernard, Ismael; Allain, Gwenhael; Auby, Isabelle; Plus, Martin; Drean, Tugdual; Gasmi, Sonia; David, Valérie; Pouvreau, Stephane; Maurer, Daniele. |
| De 2009 à 2011, le captage à Arcachon fut particulièrement mauvais. Des pontes tardives associées à de faibles quantités de larves “petites” indiquaient un problème probablement au niveau de la maturation ou de la ponte. Le programme FéLiBA consiste en un zoom, pour l’année 2013, sur la Fécondité des huîtres creuses en Lien avec la qualité de l’eau du Bassin d’Arcachon. Ce programme s’est traduit par différentes actions de terrain. Tout d’abord, la maturation des huîtres issues du captage d’Arcachon ou de Marennes-Oléron a été suivie à Arcachon (site du Tès) et comparée avec celle de la Rade de Brest (pointe du Château) au cours de l’année 2013. Puis, un bilan de la maturation des huîtres sauvages d’Arcachon a été établi fin juin 2013. La ponte a également... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00179/29002/27428.pdf |
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| Allain, Gwenhael. |
| A la suite des mortalités massives d'huîtres creuses (Crassostrea gigas) observées en France dans tous les bassins de production ostréicoles, une étude épidémiologique a été engagée. Débutée en octobre 2008, son objectif est d'aider à l'identification de la (ou les) causees) de ces mortalités. Elle comprend deux parties. Une première phase, descriptive, a consisté à décrire la distribution des mortalités dans le temps et l'espace, ainsi que la population touchée, puis à formuler des hypothèses concernant l'implication d'un ou de plusieurs facteurs de risque dans le phénomène observé. La seconde partie est une étude analytique dont l'objectif est de tester les hypothèses formulées lors de l'enquête épidémiologique descriptive, en étudiant l'association... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00306/41766/40979.pdf |
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| Miossec, Laurence; Allain, Gwenhael; Arzul, Isabelle; Francois, Cyrille; Garcia, Celine; Cameron, Angus. |
| En 2008, des mortalités massives d'huîtres creuses (Crassostrea gigas) ont été recensées en France pendant l'été. Ce phénomène, observé de façon récurrente sur les côtés françaises depuis le milieu des années 70, a présenté un caractère exceptionnel en 2008 car il a été observé simultanément dans tous les bassins ostréicoles. De plus, les taux de mortalité calculés ont été particulièrement élevés (80 à 100 % pour de nombreux lots). La détection, fréquente et souvent simultanée, d'herpèsvirus OsHV1 et de plusieurs bactéries de la famille des Vibrionacées dans le cadre de la surveillance menée par le réseau national Repamo (réseau de pathologie des mollusques) a mis en évidence le caractère infectieux de l'épisode épidémique 2008. Une étude épidémiologique a... |
| Tipo: Text |
Palavras-chave: France; Crassostrea gigas; Huîtres; Mortalités; Epidémiologie. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/acte-6771.pdf |
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| Soletchnik, Patrick; Mazurie, Joseph; Allain, Gwenhael; Bedier, Edouard; Benabdelmouna, Abdellah; Blin, Jean-louis; Bouquet, Anne-lise; Cochet, Hélène; Degremont, Lionel; Gaussem, Florian; Gervasoni, Erika; Glize, Philippe; Petton, Bruno; Roussel, Pierre-yves; Pernet, Fabrice. |
| This paper summarizes knowledge about relations between husbandry practices and oyster spat mortalities since 2008 in France. These relations are strictly analyzed from a panel of experiments set on the shore (in outdoor experiments) by Ifremer teams and technical institutes all over French coasts. Results show some practices are able to reduce spat mortality with some influencing factors relevant of spat quality (sanitary status, natural or genetic selection) or husbandry practices. Spat “free” of virus is able to survive up to 90% when it is isolated and confined in ponds or nursery, during an epidemic crisis. When outbreaks occurred in oyster beds, natural or nursery spat died in almost same proportions. In 2010, some studies conducted in Mediterranean... |
| Tipo: Text |
Palavras-chave: Surmortalité; Naissain; Huître creuse; OsHV-1; Pratiques culturales; Mortality; Spat; Cupped oyster; Crassostrea gigas; OsHV-1; Cultural practices. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00032/14280/25847.pdf |
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| Gasmi, Sonia; Bernard, Ismael; Pouvreau, Stephane; Maurer, Daniele; Schaal, Gauthier; Ganthy, Florian; Cominassi, Louise; Allain, Gwenhael; Sautour, Benoit; David, Valerie. |
| In macrotidal coastal ecosystems, spatial heterogeneity of the water column properties is induced by both oceanic and continental influences. Hydrodynamic processes generate a land-sea gradient of environmental conditions, affecting the biological performances of sedentary organisms. The aim of the present study is to establish an extensive spatial assessment in the reproductive investment of the wild Pacific oyster Crassostrea gigas in Arcachon Bay. This is done by looking for a relationship between the Lawrence and Scott condition index (LSCI) and two tidal processes: the immersion level (IL) and the local oceanic flushing time (LoFt). The LSCI of C. gigas was assessed, just before gamete release, at 68 sampling stations in Arcachon Bay. Oyster... |
| Tipo: Text |
Palavras-chave: Reproductive investment; Crassostrea gigas; Macrotidal lagoon; Immersion level; Oceanic flushing; Environmental variability. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00357/46803/46670.pdf |
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| Renault, Tristan; Allain, Gwenhael; Arzul, Isabelle; Chollet, Bruno; Cobret, Laetitia; De Decker, Sophie; Faury, Nicole; Ferrand, Sylvie; Francois, Cyrille; Garcia, Celine; Haffner, Philippe; Joly, Jean-pierre; Miossec, Laurence; Morga, Benjamin; Nicolas, Jean-louis; Omnes, Emmanuelle; Pepin, Jean-francois; Saulnier, Denis; Schikorski, David; Segarra, Amelie. |
| Abnormal mortality outbreaks occurred in the majority of Pacific oyster (Crassostrea gigas) producing areas in France in 2008 during the summer period. These outbreaks were usually sudden and severe (up to 100%) and affected essentially spat (oysters less than 1 year-old) and juveniles (12 to 18 month-old oysters). Crassostrea gigas was the single affected species Mortality outbreaks were first observed from mid May to mid June in Brittany, Vendée, Charente Maritime and Mediterranean coast A second episode of massive mortality events was reported at the end of June and the beginning of July. All oyster production sites were affected except some particular locations including Arcachon Bay and Brittany. Mortality occurred latter in Arcachon Bay in August.... |
| Tipo: Text |
Palavras-chave: Abnormal mortality; Oysters; Crassostrea gigas; Pathogens. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00014/12554/9420.pdf |
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| Allain, Gwenhael; Petitgas, Pierre; Lazure, Pascal. |
| A growth and survival model of the early life stages was run along virtual drift trajectories tracked in a hydrodynamic model to simulate the annual recruitment process of anchovy (Engraulis encrasicolus) in the Bay of Biscay (NE Atlantic). These biophysical simulations concerning three different years were analysed in order to investigate the influence of environment and spawning dynamics on the survival of larvae and juveniles. The location of space-time survival windows suggested major environmental mechanisms involved in simulated recruitment variability at the different scales - retention of larvae and juveniles in favourable habitats over the shelf margins and turbulence effects. These small-scale and meso-scale mechanisms were related to the... |
| Tipo: Text |
Palavras-chave: Turbulence; Retention; Recruitment; Physical biological interactions; Larval survival; IBM; Biscay; Anchovy. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3423.pdf |
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| Registros recuperados: 11 | |
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