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| Registros recuperados: 136 | |
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| Alderman, D. J.; Gras, Paul. |
| During April and May of this year, there has been a heavy mortality of Portuguese oysters, Crassostrea angulata LmK., which were imported into Britain from the River Tagus (Portugal) in March. Losses in some cases exceeded 90 per cent. The symptoms shown by the dyring oysters are the same as those seen in Britain and France in C. angulata in 1967 and 1968. Farley described the general symptoms in oysters (C. virginica Gmelin) dying of prolonged functional or infectious disease. These gross symtoms appear to be similar in the case of several different diseases including the present European mortality. |
| Tipo: Text |
Palavras-chave: Gill; Crassostrea angulata; Oysters. |
| Ano: 1969 |
URL: http://archimer.ifremer.fr/doc/1969/publication-5931.PDF |
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| Longere, Paul; Dorel, Didier; Marin, Jean. |
| 2 ponds (or lagoon) were studied in order to establish the economic possibilities of their exploitation for oysters. Bathymetric and sediment maps were produced using methods described. They indicate a morphological similarity between the ponds, with a superficial broken bed and a regular, flat or gently sloping bed beyond 7 m, the general form reflecting the aerial relief of the adjacent `coast'. The deeper regions had mud or clay sediment, while the edges of the ponds were covered with sand. In more detailed studies it was evident that the banks of Diane were more regular and steep than those of Urbino, and that only in the latter was there a good relationship between the depth of water and the carbon/nitrogen ratio. Differences are thought to relate to... |
| Tipo: Text |
Palavras-chave: Corsica; Studies; Exploitation; Oysters; Sedimentologic; Bathymetric. |
| Ano: 1972 |
URL: http://archimer.ifremer.fr/doc/1972/publication-2068.pdf |
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| Zanette, Yvan; Garnier, Jacqueline. |
| The evolution of microbial biomass based on chlorophyll a, pheopigments, proteins, particulate carbon and nitrogen, ATP and total viable aerobic bacterias measurements, is studied on three oyster ponds in relation with different densities of reared oysters Crassostrea gigas (Thunberg). Chlorophyll a important amounts characteristics of theses middles (13 to 100µg.1(1) are in part consumed when the density of oysters is important, comparatively ATP increase to 30µg.1(1). With important values of (ATP/carbon) 10(3) ratios, upper than 10, we could think that the development of large silicified phytoplanktonic species should be favoured by oysters particularly the diatom Navicula ostrearia (Bory) |
| Tipo: Text |
Palavras-chave: Navicula ostrearia; Marennes Oleron; Phytoplanctonic biomass; Microbial biomass; Oysters; Crassostrea gigas; Navicula ostrearia; Marennes Oléron; Claire; Biomasse microbienne; Biomasse phytoplanctonique; Huîtres; Crassostrea gigas. |
| Ano: 1981 |
URL: http://archimer.ifremer.fr/doc/1981/acte-2936.pdf |
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| Heral, Maurice; Robert, Jean-michel; Truquet, Isabelle; Barbaroux, Olivier; Garnier, Jacqueline; Razet, Daniel. |
| Values of nitrogen nutrients (ammonia, nitrite and nitrate) are compared with values of total organic nitrogen and urea. In summer, the consumation by micro and macrophytes is added to less important telluric input of nineral nitroge. However, an important provision of organic nitrogen remains. On the contrary, in winter, organic nitrogen does not represent more than 10% of total nitrogen. The autors postulate that populations of oysters are at the starting point of the organic nitrogen production cycle. |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Biochimical composition; Oysters; Crassostrea gigas; Composition biochimique; Huîtres. |
| Ano: 1981 |
URL: http://archimer.ifremer.fr/doc/1981/acte-2940.pdf |
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| Alzieu, Claude; Heral, Maurice. |
| The toxic effect of trialkyltin compounds is used in antifouling paints to protect vessels against biofouling organisrns. Tributyltin oxide (TBTO) or fluoride (TBTS) leaches by diffusion from the paint layer into the seawater. Trialkyltin compounds in aqueous solutions are resistant to hydrolysis and biodegradation, but are rapidly converted into diakyl, monoalkyl and inorganic tin by UV irradiation. As inhibiting agents of the oxidative phosphorylation, organotin compounds are extremely dangerous for aquatic organisms such as molluscs. The following estimated toxicity levels for Crassostrea gigas oyster larvae have been put forward : at 100 µg.l(1) the fecondation is inhibited, at 10 µg.l1 the already of 20 % of the eggs is affected larval development... |
| Tipo: Text |
Palavras-chave: Toxicity; Fluoride; Tribultyltin oxide; Toxic effect; Oysters; Crassostrea gigas. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/publication-2931.pdf |
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| Bacher, Cedric; Baud, Jean-pierre; Bodoy, Alain; Deslous-paoli, Jean-marc; Dreno, Jean-paul; Heral, Maurice; Maurer, Daniele; Prou, Jean. |
| An assessment of the reared stocks of the Pacific oyster (Crassostrea gigas ) has been recently conducted on the major French areas of molluscs culture. The methodology proposed included both estimates of densities obtained by subsampling in the field, and aerial photographs which covered the cultivated, intertidal area. The size and the number of samples were designed to reach a precision of 10% on the final assessment in each area. The field work consisted in weighing and counting the oyster in unit areas of 0.5 m2 for the bottom culture or in trays or bags, for the off bottom technique. These results give a better knowledge of the technique evolution and of the general structures in the cultivated areas. |
| Tipo: Text |
Palavras-chave: Modeling; Estimation; Stocks; Crassostrea gigas; Oysters. |
| Ano: 1986 |
URL: http://archimer.ifremer.fr/doc/1986/acte-2864.pdf |
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| Bachere, Evelyne; Chagot, Dominique; Tige, Gilbert; Grizel, Henri. |
| Considering the epizootics which affect the French stock of flat oysters, Ostrea edulis (Grizel, 1985), trials to introduce an Australian oyster, Ostrea angasi, have been undertaken. The spat produced in a hatchery from breeders imported from Australia were reared in the south ofBrittany and in Normandy (Bougrier et al., 1986). Following mass mortalities (65% of individuals) a haplosporidian was observed in this species. Sporogenesis of the parasite was studied using Iight and electron microscopy. |
| Tipo: Text |
Palavras-chave: Haplosporidian; Parasitology; Pathology; Ostrea angasi; Oysters. |
| Ano: 1986 |
URL: http://archimer.ifremer.fr/doc/1986/acte-3112.pdf |
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| Bodoy, Alain. |
| The natural mortality of oysters could by considered, in a man controlled ecosystem, as the result of the action of biological factors, and human factors other then the harvest of the population. Such mortalities need to be estimated in order to be used in population dynamics, as a tool for management purposes. ln Marennes-Oleron bay, different ways of estimating the natural mortality are available. Several oyster farms were monitored for assessing growth, mortality and production in rearing conditions. Furthermore, an experimental framework which includes 15 stations gave an appraisal of the same factors under controlled conditions. Finally, another estimate will be soon available by comparin9 the number of recruited oysters, and the number of oyster... |
| Tipo: Text |
Palavras-chave: Marennes Oleron; Mortality; Crassostrea gigas; Oysters. |
| Ano: 1986 |
URL: http://archimer.ifremer.fr/doc/1986/acte-2962.pdf |
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| Registros recuperados: 136 | |
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