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| Registros recuperados: 136 | |
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| Gerard, Andre; Naciri, Yamama; Peignon, Jean-marie; Ledu, Christophe. |
| A novel method using 6-dimcthylaminopurinc (6-0MAP) has recently been demonstrated to be a good triploid inductor for bivalve molluscs. The effects of 6-DMAP concentration, timing of treatment after fertilization and treatment duration on survival and triploid induction of Crassostrea gigas (Thunberg) embryos were examined. An influence of sperm concentration was also detected and discussed. Survival to D-stage was inversely related to 6-DMAP concentration and the percentage of triploids was shown to be 6-DMAP dose dependent. Two optimal moments for treatment application were determined corresponding to extrusions of the first and second polar bodies. Optimal treatment of 450 µmol/l 6-DMAP beginning 15 min after fertilization over a 10 min period yielded... |
| Tipo: Text |
Palavras-chave: Genetic; Triploid induction; Crassostrea gigas; 6 DMAP; Triploid; Oysters. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/1994/publication-3198.pdf |
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| Lapegue, Sylvie; Boudry, Pierre. |
| Oysters are among the most familiar of all marine invertebrate taxa. However our knowledge of oyster phylogeny and systematics is fragmentary. This is principally due to the plastic growth patterns of these animals, which result in a wide range of overlapping, ecophenotypic variants that greatly reduce the value of analysis based on shell morphology. Besides that, many intentional or accidental anthropogenic transfers have emphasised this situation. In several cases of misclassification or misidentification of oysters, DNA molecular data, have provided valuable new insights on the tracing of introductions or more generally on the phylogeographic relationships between oyster species. We will illustrate this issue with recent case studies from our lab on... |
| Tipo: Text |
Palavras-chave: Genetic; Ostreola stentina; Crassostrea honkongensis; Crassostrea gigas; Crassostrea angulata; Oysters; Population genetics. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/acte-3475.pdf |
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| Lapegue, Sylvie; Boudry, Pierre; Goulletquer, Philippe. |
| Originating from the north eastern Asia, Crassostrea gigas is endemic to Japan, but has been introduced and translocated, mainly for aquaculture purpose, into several countries, almost worldwide (1). In North America, the species can be found from Southeast Alaska to Baja California, while in European waters the species is cultured from Norway to Portugal as well as in Mediterranean Sea (Fig.1) (2). Biological characteristics make it suitable for a wide range of environmental conditions, although it is usually found in coastal and estuarine areas within its natural range. Although highly variable, the invasiveness pattern of C. gigas has been demonstrated in several countries and therefore considered as a pest or a noxious species in those areas (3). |
| Tipo: Text |
Palavras-chave: Genetics; Ecology; Crassostrea gigas; Biology; Oysters. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/acte-3322.pdf |
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| Goulletquer, Philippe; Joly, Jean-pierre; Gerard, Andre; Le Gagneur, Eric; Moriceau, Jacques; Peignon, Jean-marie; Heurtebise, Serge; Phelipot, Pascal. |
| Triploid oysters Crassllstrea gigas were: produced in 1990 by treating fertilized eggs with cytochalasin B (CS). Triploids, treated diploids, and controls were deployed early 1991 in a high carrying capacity ecosystem on the Eastern Coast of Normandy (France). A monthly monitoring in 1992 showed that triploids yielded significantly higher growth rate and biochemical composition. However, growth was more heterogeneous. No evidence was found for a length or weight bimodal frequency distribution within triploid groups after a 26 months rearing cycle. Triploids showed retardation of gametogenesis. Carbohydrates content in triploids remained almost constant (40%) from June to September. Their survival rates were significantly lower than controls. Moreover... |
| Tipo: Text |
Palavras-chave: Biochemical compostion; Survival; Carrying capacity; Triploid; Growth; Oysters; Crassostrea gigas; Composition biochimique; Survie; Capacité trophque; Triploïdes; Croissance; Huîtres; Crassostrea gigas. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/1996/publication-3088.pdf |
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| Taris, Nicolas; Ernande, Bruno; Mccombie, Helen; Boudry, Pierre. |
| The life histories of oysters in the genus Crassostrea, like those of most marine bivalves, are typified by high fecundity and low survival in nature. Rearing conditions in hatcheries however ensure optimized density, diet, and temperature. Hatcheries are becoming increasingly important for the production of juveniles in aquaculture, and their culture practices often include culling of slow growing larvae to reduce and synchronize the time taken to reach settlement. Because previous studies have found substantial genetic variation for early life developmental traits in Crassostrea gigas, these culling practices are likely to cause highly different selective pressures in hatcheries from those in the natural environment. We studied the phenotypic and genetic... |
| Tipo: Text |
Palavras-chave: Oysters; Larvae; Hatchery; Genetic diversity; Culling; Crassostrea gigas. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1677.pdf |
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| Normand, Julien; Huvet, Arnaud; Fabioux, Caroline; Raguenes, Morgane; Boudry, Pierre. |
| Genetic improvement of the Pacific oyster, Crassostrea gigas, can be achieved through triploidisation, which leads to partially sterility, allowing higher growth and survival together with improved meat quality during the reproductive period. Most triploids are not fully sterile and the genetic and environmental factors involved in their partial fertility remained to be investigated. We examined gametogenesis by image analysis of histological cross sections in diploid (2n) and triploid oysters obtained either by crossing tetraploids and diploid broodstock (« natural » triploids: 3nn) or from second polar body retention (« chemical » triploids: 3nc). 5-month old triploid spat reared in a standard intensive nursery system only showed a reduction of 50% of... |
| Tipo: Text |
Palavras-chave: Gametogenesis; Triploid; Crassostrea gigas; Genetic; Oysters. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/acte-3327.pdf |
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| Haberkorn, Hansy; Tran, Damien; Massabuau, Jean-charles; Ciret, Pierre; Savar, Veronique; Soudant, Philippe. |
| The complexity of the relationships between Alexandrium minutum (Am.) concentration in the water ([A.m.](w)), Paralytic Shellfish Poisoning contamination in the digestive gland ([PSP](dg)) and valve behavior was explored in oysters Crassostrea gigas. Two experiments were conducted, during which oysters' valve behaviour were analyzed. Oysters, first acclimated for 10-days with the non harmful microalgae Heterocapsa triquetra (H.t.), were exposed to four microalgae mixtures at constant total concentrations of 10 x 10(3) cells ml(-1) (experiment-1) and 5 x 10(3) cells ml(-1) (experiment-2): 100% Am.; 50% A.m.-50% H.t.; 25% A.m.-75% H.t.; 100% H.t. At the end of experiment-2, [PSP](dg) were measured. At 10 x 103 cells ml(-1), the microalgal ingestion decreased... |
| Tipo: Text |
Palavras-chave: Harmful algae; Oysters; Behavioral responses; Algae concentration; Toxin accumulation. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00041/15195/12617.pdf |
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| Degremont, Lionel; Bedier, Edouard; Soletchnik, Patrick; Ropert, Michel; Huvet, Arnaud; Moal, Jeanne; Samain, Jean-francois; Boudry, Pierre. |
| Summer mortality has been reported in the Pacific oyster, Crassostrea gigas, for many years in different parts of the world. The causes of this phenomenon are complex. The multidisciplinary program "MOREST", coordinated by IFREMER, was initiated to understand the causes of summer mortality of Crassostrea gigas juveniles in France and to reduce its impact on oyster production. Within this program, three successive groups of bi-parental families were bred in a hatchery in 2001 and placed in the field during summer in three sites (Ronce, Riviere d'Auray, and Baie des Veys). This paper reports the relative importance of family, site and field placement timing for three characters of major importance for oyster production: survival, growth, and yield. At the... |
| Tipo: Text |
Palavras-chave: Juvenile; Crassostrea gigas; Oysters; Yield; Growth; Survival. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-1693.pdf |
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| Berthe, Franck. |
| Of the 75 laboratories contacted through the survey, 54 answered, 14 of which are partially or totally devoted to mollusc diseases. In fact, only 4 laboratories are devoted full-time to this work. Of the 14 laboratories that declared to work on the diagnosis of mollusc diseases, 12 stated that they worked with mussels, 12 with oysters, 9 with clams and 8 with other mollusc species. This is coherent with available production information. According to production data in 2001 (FAO source), the main mollusc species in the region are the blue mussel, Mytilus edulis (297,485 tonnes), the Mediterranean mussel, Mytilus galloprovincialis (131,014 tonnes), the Pacific cupped oyster, Crassostrea gigas (127,323 tonnes, an important part of which is produced on the... |
| Tipo: Text |
Palavras-chave: Bonamia existiosus; Bonamis ostreae; Bonamiosis; Marteilia sydneyi; Marteilia maurini; Marteilia refringens; Marteiliosis; Perkinsus marinus; Perkinsus olseni; Perkinsus atlanticus; Perkinsosis; Vibriosis; Herpes like virus; Oysters; Pathology; Mollusc diseases. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-3300.pdf |
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| Cantin, Christian. |
| Après avoir rapidement présenté le Bassin d'Arcachon et son environnement (situation géographique et réseau hydrologique), et rappelé quelques données sur l'ostréiculture, le tourisme et le réseau d'assainissement, le réseau de surveillance microbiologique (REMI) est décrit depuis sa mise en place en 1989 (réseau principal) jusqu'à son évolution en 1995 avec la mise en oeuvre d'un réseau étendu. Les résultats des analyses effectuées mensuellement sur les huîtres, au cours de ces sept années, sont présentés pour chaque station sous forme graphique, répartis en quatre secteurs géographiques. lls ont été interprétés pour chaque réseau en fonction des quatre zones de salubrité définis par l'arrêté relatif aux classements des zones de production, et, ensuite... |
| Tipo: Text |
Palavras-chave: Bactériologie; Huîtres; Bassin d'Arcachon; Bacteriology; Oysters; Bay of Arcachon. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00427/53819/54808.pdf |
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| NoV is highly infectious, and there is no threshold infectivity limit for NoV detected by PCR. The probability of becoming infected increases with the dose but depends also on the characteristics of the organism, the food matrix and the host factors. The relationship between the number of infectious virus particles and the number of virus genome copies detected by quantitative PCR is not a constant, and it is important to realise that the infectious risk associated with low level positive oysters as determined by real-time PCR may be overestimated. Quantitative data on viral load from areas compliant with current EU legislative requirements (E. coli standards) during January-March 2010 in 3 selected member states, show that a viral limit of 100, 200, 500,... |
| Tipo: Text |
Palavras-chave: Norovirus; Oysters; Diagnostic methods; Microbiological criteria; Treatment; Control. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00066/17735/15256.pdf |
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| Broquard, Coralie; Martinez, Anne-sophie; Maurouard, Elise; Lamy, Jean-baptiste; Dégremont, Lionel. |
| Understanding sex determination in the Pacific oyster Crassostrea gigas, a sequential hermaphrodite, can provide prospective on the evolution of sex-determining systems for comparative reproduction from an evolutionary perspective. Surprisingly, this mechanism is still poorly understood. To date, sex ratio and sex change have never been studied at the individual level for a large size group and long-term monitoring. To this purpose, we performed an ambitious individual long-term follow-up (6 years) on a large population (cohort 1: 7488 oysters) produced from wild oysters, as well as for a second population produced from the cohort 1 (cohort 2: 4320 oysters). All oysters were individually sexed from 2014 to 2019. For the cohort 1, our results showed a... |
| Tipo: Text |
Palavras-chave: Sex-ratio; Sex change; Oysters; Hermaphroditism; Crassostrea gigas. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00587/69868/67845.pdf |
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| Renault, Tristan. |
| Mortalities in a number of commercially important mollusc species have been associated with the detection of viruses belonging to several families. The first description of a virus was in adult eastern oyters, Crassostrea virginica, with the detection of virus particles resembling members of the family Herpesviridae. Subsequently, mass mortalities in French stocks of adult Portuguese oysters, C. angulata, were associated with irido-like virus infection. Other viruses observed in molluscs are described as members of the families Iridoviridae, Papovaviridae and Reoviridae. Little information is available on viral infections that affect molluscs due to primarily to the inadequacy of diagnostic methods that are employed when mass mortality events occur. Most... |
| Tipo: Text |
Palavras-chave: Virus; Scallops; Picornavirus; Oyter herpesvirus 1; Oysters; Molluscs; Irido Like virus; Diseases; Herpesvirus; Clams; Bivalves; Birnavirus; Abalones. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4932.pdf |
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| Dubois, Stanislas; Orvain, Francis; Marin Leal, Julio César; Ropert, Michel; Lefebvre, Sébastien. |
| Oyster culture structures support a host of epibionts belonging to the same suspension-feeding guild, which are considered to be potential competitors for food with cultivated oysters. In an intertidal shellfish ecosystem on the northern French coast, an approach based on stable isotopes (C-13 and N-15) was used to investigate intra- and interspecific food resource partitioning among cultivated oysters and the main associated wild sessile epibionts such as polychaetes, barnacles, mussels and ascidians. The main objective of the present study was to determine inter- and intraspecific food partitioning, along with small-scale spatial variability, within the guild of suspension feeders. We demonstrated that interspecific competition was limited among... |
| Tipo: Text |
Palavras-chave: Trophic plasticity; Spatial variability; Stable isotopes; Sessile epibionts; Oysters; Shellfish. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2626.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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| Registros recuperados: 136 | |
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