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| Registros recuperados: 148 | |
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| Prou, Jean; Heral, Maurice; Goulletquer, Philippe; Forget, Maïté; Bougrier, Serge; Razet, Daniel. |
| The project of cultivation of oyster has been designed to evaluate the growth rate, the mortality, the reproductive effort, production and biochemical composition of the oyster function of the density and the depth. This plan was intended: - to build model of growth rate, - to demonstrate the action of the different parameters on growth rate (temperature, food effect...), - to evaluate the density effect to see if the available food could be a limiting factor, - to estimate the effect of the depth joined to the impact of the high turbidity near the bot tom, - to detect the mortality related to the prevalence of diseases. The project began in July 1989 by dredging 20 000 small oysters at the mouth of the Patuxent River near Cove Point. Three experimental... |
| Tipo: Text |
Palavras-chave: Physiology; Seasonal variation; Biochemical composition; Density; Crassostrea virginica; Cheseapeake Bay. |
| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00200/31104/29503.pdf |
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| Goulletquer, Philippe; Razet, Daniel; Prou, Jean; Garnier, Jacqueline; Taillade, Sylvie; Heral, Maurice; Peyre, R; Faivre, C. |
| Etant donné que la production de mollusques (palourdes ou huîtres) est limitée à 0,8 kg à 1 kg au m2 soit 40 à 50 palourdes adultes de 20 g au m2, il est intéressant d'essayer de forcer cette production en augmentant la production primaire qui est le facteur limitant de la production de palourdes. Cette production primaire dépend des apports en sels nutritifs en effet les travaux antérieurs de Zanette (1979), de Zanette et Garnier (1980), de Robert (1984) ont mis en évidence que les biomasses phytoplanctoniques ne peuvent dépasser un certain seuil à cause de l'épuisement progressif en sels nutritifs. Robert et al. (1984) ont mis en évidence, dans les claires de la Baie de Bourgneuf que l'azote est le premier facteur limitant de la croissance... |
| Tipo: Text |
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| Ano: 1985 |
URL: http://archimer.ifremer.fr/doc/00389/50053/50641.pdf |
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| Heral, Maurice; Alzieu, Claude; Caux, O.; Razet, Daniel; Garnier, Jacqueline. |
| The toxicity of organostannic compounds has been demonstrated for the oyster Crassostrea gigas through larval (His & Robert, 1980) and adult stages (Alzieu & al., 1980, 1981). In parallel, these authors demonstrated the accumulation of tin in experimentally contaminated oysters as well as the part played by TBT fluorides in growth disturbance (Héral & al. 1981) and oyster shell deformity (Alzieu & al., 1981). In this work, we precise the TBT fluoride toxic doses causing, after 35 days, a mortality of 100 % at a concentration of 0.5 µgl-1. In addition, the different TBT organic salts (acetate, methacrylate and fluoride) are tested and TBT fluoride appears to be the more toxic. Authors then tackle breathing and ATP measurements as stress... |
| Tipo: Text |
Palavras-chave: Tributyletain; Crassostrea gigas; Toxicité. |
| Ano: 1983 |
URL: http://archimer.ifremer.fr/doc/1983/acte-6216.PDF |
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| Feuillet-girard, Michelle; Heral, Maurice; Sornin, Jean-marc; Deslous-paoli, Jean-marc; Robert, Jean-michel; Mornet, Francoise; Razet, Daniel. |
| The respective influences of the sediment and of oyster (Crassostrea gigas) farming on the accumulation and the recycling of different forms of organic and inorganic nitrogen are described. Fluxes of dissolved inorganic and organic forms of nitrogen were studied between the water column, the water overlying the sediment and the pore waters, while for particulate forms the fluxes were studied between suspended material, the "biodeposits" (faeces and pseudofaeces of Crassostrea) and the sediment. The flux of inorganic nitrogen amounts to 10.5 106 g.m(-2). Yr(-1), while that of organic nitrogen is half this figure. The particulate flux is 15.106 g.m(-2).yr(-1). On the other hand, the phytoplanktonic nitrogen accounts for only 6% of the total particulate... |
| Tipo: Text |
Palavras-chave: Marenne Oleron; Sediment; Pore water; Interface; Crassostrea gigas; Nitrogen; Marennes Oléron; Sédiment; Eau interstitielle; Adsorption; Interface; Crassostrea gigas; Azote. |
| Ano: 1988 |
URL: http://archimer.ifremer.fr/doc/1988/publication-2878.pdf |
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| Heral, Maurice. |
| Le bassin de Marennes-Oléron, premier bassin ostréicole français est une baie chroniquement en surcharge. Les déficits de croissance et l'accroissement des mortalités non liées à des pathogènes se sont accentués parallèlement aux anomalies climatiques. Les 3 années de sécheresse (1989-1992) ont montré la grande dépendance pour la productivité de cet écosystème, aux apports d'eau douce estivaux, d'où les conflits pour l'usage de l'eau qui sont apparus. Sur le cheptel affaibli du bassin de Marennes-Oléron en 1993 a été identifiée une chlamydie-like qui altère les branchies des huîtres et qui devrait être un élément supplémentaire de fragilisation du cheptel. La conchyliculture en Charente-Maritime regroupe 4 500 conchyliculteurs qui exploitent 2 800... |
| Tipo: Text |
Palavras-chave: Etude de site; Ostréiculture; Eau profonde; Zone de Culture; Huîtres creuses; Crassostrea gigas. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00048/15900/13328.pdf |
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| Goulletquer, Philippe; Heral, Maurice. |
| Le développement de la mytiliculture dans un bassin conchylicole peut aboutir à la surexploitation du site avec des conséquences néfastes pour les populations en cours d'exploitation. Pour cette raison, il est particulièrement important de développer un plan d'aménagement de bassins tels que le Pertuis Breton considérant l'ensemble des utilisateurs de cet espace. A moyen terme, le développement d'un modèle mathématique est l'outil plus approprié pour tester et valider les différents schémas d'aménagement, permettant ainsi de limiter l'impact sur l'existant. Pour un tel modèle, une parfaite connaissance des caractéristiques biologiques et physico- chimiques du milieu est nécessaire. Au délà de la biomasse en élevage, sa répartition spatiale, ses besoins... |
| Tipo: Text |
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| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00406/51771/52369.pdf |
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| Collet, Bertrand; Boudry, Pierre; Bougrier, Serge; Heurtebise, Serge; Phelipot, Pascal; Ledu, Christophe; Morand, Berenice; Heral, Maurice; Gerard, Andre. |
| A European programme (GENEPHYS) was launched in 1996 to study the genetic basis and variability of physiological characters involved in growth in Crassostrea gigas. This research programme was a prerequisite for any genetic selection programme on physiological functions. Research groups from Ireland, England, Greece and France are involved in this project and participate in genetic analyses (allozymes and microsatellites) and physiological analyses (ecophysiology, enzymology, stress proteins). Ifremer at La Tremblade was responsible for producing the biological material while Ifremer-CREMA (human-influenced marine ecosystems research centre) was responsible for carrying out non-destructive physiological analyses. |
| Tipo: Text |
Palavras-chave: Sélection génétique; Croissance; Crassostrea gias; Génétique. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/1997/acte-3243.pdf |
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| Heral, Maurice. |
| Growth of molluscs raised in coastal zones, where the water exchange rate is low, appears to be limited, once a certain biomass level is attained, by the availability of food, making it necessary to determine as accurately as possible the trophic capacity of an ecosystem. This paper analyses the various sources of food for molluscs. It would appear that dissolved organic substances play a major role, providing up to half the energy necessary for their metabolism. Particulate material is filtered by molluscs in proportion to their size, with optimum filtration rates varying with species. The negative effect on meat production of high mineraI seston rates is demonstrated, and an analysis provided of the respective role of each component of organic matter.... |
| Tipo: Text |
Palavras-chave: Evaluation; Carrying capacity; Molluscs; Ecosystems; Cochyliculture; Ecosytemes; Molluscs; Evaluation; Capacité biotique. |
| Ano: 1985 |
URL: http://archimer.ifremer.fr/doc/1985/acte-2945.pdf |
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| Soletchnik, Patrick; Goulletquer, Philippe; Heral, Maurice; Razet, Daniel; Geairon, Philippe. |
| This ecophysiological study was conducted on the Japanese oyster (Crassostrea gigas) reared in Marennes-Oléron bay (France), in May 1992. Measurements were achieved using natural food conditions on three different days (a, b, c) at different tide levels (coefficient of 49, 57, and 88). Total particulate matter was continuously monitored with a micro-computer and a turbidimeter probe. The "consumption" function was calculated using a new formula allowing for particulate leakage prior to the pre-ingestive particle sorting. This particle leakage represents a passive loss of particles flowing through the branchial filter. Comparisons of the consumption and absorption rates of organic matter and chlorophyll a showed significant differences between seston... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Consumption rate; Selection efficiency; Absorption rate; Energetic budget; Organic matter; Chlorophyll alpha; Marennes-Oleron bay. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/1996/publication-3086.pdf |
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| Heral, Maurice; Bacher, Cedric; Razet, Daniel; Prou, Jean; Deslous-paoli, Jean-marc. |
| Le bassin conchylicole de Marennes-Oléron assure 40 % des 100 000 tonnes d ' huîtres commercialisées annuellement en moyenne en France (20 000 emplois, 1 milliard de chiffre d'affaire) . La modélisation des équilibres qui s'établissent entre l es stocks mis en culture , et la production annuelle , réalisée par la station IFREMER de La Tremblade , a mis en évidence les résultats suivants : Lorsque la biomasse augmente : a) La production plafonne vers 40 000 tonnes pour une biomasse de l'ordre de 80 000 tonnes avec l'huître japonaise, ce qui correspond à une biomasse équivalente de 130 000 tonnes d'huîtres portugaises. b) La durée du cycle de production d'une huître de 70 g passe de 2 ans à 4 ans. c) Les mortalités courantes passent simultanément de 20 % à... |
| Tipo: Text |
Palavras-chave: Production; Ostréiculture; Biomasse; Modélisation; Marennes Oléron. |
| Ano: 1986 |
URL: http://archimer.ifremer.fr/doc/00048/15909/13338.pdf |
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| Heral, Maurice. |
| The total marine molluscs produced by aquaculture had increased from 1984 to 1990 by 1 000 000 tons going from 1 993 985 tons to 2 964 688 tons. The oyster production remained constant with 870 000 tons. Crassostrea gigas, the Japanese oyster, represented more than 80 % of the oyster production but high mortalities appeared in different countries connected to end of winter and summer mortalities and development of new diseases. The cultivation of Crassostrea virginica, the American oyster, was limited (80 000 tons) by the spreading of two diseases (MSX and dermo) destruction of habitat and over-exploitation. Production of the fiat oyster Ostrea eduIis was still very limited by the presence of the Bonamia diseases in a11 the countries except on... |
| Tipo: Text |
Palavras-chave: Ostrea edulis; Crassostrea virginica; Crassostrea gigas; Huîtres; Culture; Production; Ostréiculture. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/1993/acte-3067.pdf |
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| Deslous-paoli, Jean-marc; Heral, Maurice; Goulletquer, Philippe; Boromthanarat, Wilaiwan; Razet, Daniel; Garnier, Jacqueline; Prou, Jean; Barille, Laurent. |
| The study of cultivated ecosystems, once the trophic capacity ha! been determined and the molluscan stocks estimated, requires a knowledge of the evolution of the seasonal consumption of food by molluscs in natural conditions. For Crassostrea gigas, Mytilus edulis, Cerastoderma edule, Ruditapes philippinarum, the amount and quality of food have no effect on the filtration rate, except for the high load of mineraI seston. First an increase of the filtration rate was shown for Mytilus edulis and Cerastoderma edule at the end of winter and beginning of spring. Moreover Crassostrea gigas and Ruditapes philippinarum have shown no increase or only a small summer one. This evolution did not seem to be linked with the environmental conditions (temperature,... |
| Tipo: Text |
Palavras-chave: Natural food; Bivalves; Filtration rates; Nourritures naturelles; Bivalves; Taux de filtration. |
| Ano: 1987 |
URL: http://archimer.ifremer.fr/doc/1987/publication-3304.pdf |
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| Registros recuperados: 148 | |
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