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| Registros recuperados: 41 | |
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| Soletchnik, Patrick; Ropert, Michel; Bedier, Edouard; Costil, K. S.; Dubois, Brice; Degremont, Lionel; Bouget, Jean-francois; Martin, Jean-louis; Enriquez-diaz, M.; Faury, Nicole; Le Moine, Olivier; Renault, Tristan; Gagnaire, Beatrice; Huvet, Arnaud; Moal, Jeanne; Samain, Jean-francois. |
| Field characterization of summer mortality was performed in France in the frame of the Morest project. Natural and hatchery spat were compared between three oyster production areas in France. Regardless of the natural or hatchery origin, oysters died during the reproduction period after temperature reaches 19 degree C. Thus, in southern areas, temperature accelerated gametogenesis of small spat (10mm) as well as adults, and mortality appeared for the two age classes. In contrast, sexual maturation proceeded more slowly in northern where spat mortality was lower compared to 18 months old oysters. However, critical gametogenesis and temperature were not sufficient to induce mortalities, as observed in examples with stable environment. Alternatively sediment... |
| Tipo: Text |
Palavras-chave: Seasonal variation; Oyster culture; Mortality causes; Hatcheries; Gametogenesis; Environmental factors; Crassostrea gigas; Oysters. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3348.pdf |
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| Normand, Julien; Le Pennec, Marcel; Boudry, Pierre. |
| We compared the temporal dynamics of gametogenesis in diploid and triploid Pacific oysters (Crassostrea gigas) using histology. Oysters were reared in an estuarine farming site in Brittany over 3 years and their gametogenesis was monitored over the exceptionally hot summer of 2003. Both diploids and triploids showed active gametogenesis, but a high proportion of triploids remained at early stages of gonad development. Gametogenesis of triploids was characterized by the simultaneous occurrence of gonias and immature cytes together with mature gametes rather than overall retardation, though some triploids showed complete gonad maturation. Evidence of spawning was seen in both groups, and the quantity of germinal products emitted appeared to be similar in... |
| Tipo: Text |
Palavras-chave: Triploidy; Crassostrea gigas; Oyster; Gametogenesis. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4152.pdf |
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| Jorge Eduardo, Chávez Villalba. |
| In France, 90% of the annual cup oyster (Crassostrea gigas) production comes from larvae caught in the Arcachon and Marennes-Oléron basins. However, the spat catch shows many interannual irregularities and oyster farmers increasingly say they need spat outside of the reproductive period. Thus, the role of hatcheries in Japanese oyster spat production in France is becoming increasingly evident. However, the current state of knowledge about cup oyster reproduction in controlled conditions is limited, and hatchery professionals must confront various problems to optimise treatment of genitors so as to obtain larval breeds in good health and a lengthening of the reproductive season. To respond to this, we have carried out a study on three aspects that seem... |
| Tipo: Text |
Palavras-chave: Water temperature; Biochemical studies; Gametogenesis; Breeder conditioning; Larval rearing. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/these-1456.pdf |
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| Huvet, Arnaud; Beguel, Jean-philippe; Pereira Cavaleiro, Nathalia; Thomas, Yoann; Quillien, Virgile; Boudry, Pierre; Alunno-bruscia, Marianne; Fabioux, Caroline. |
| Feeding strategies and digestive capacities can have important implications for variation in energetic pathways associated with ecological and economically important traits, such as growth or reproduction in bivalve species. Here, we investigated the role of amylase in the digestive processes of Crassostrea gigas, using in vivo RNA interference. This approach also allowed us to investigate the relationship between energy intake by feeding and gametogenesis in oysters. Double-stranded (ds)RNA designed to target the two α-amylase genes A and B was injected in vivo into the visceral mass of oysters at two doses. These treatments caused significant reductions in mean mRNA levels of the amylase genes: −50.7% and −59% mRNA A, and −71.9% and −70.6% mRNA B in 15... |
| Tipo: Text |
Palavras-chave: Alpha-Amylase; DsRNA; Gametogenesis; Marine bivalve; Dynamic energy budget. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00271/38239/36422.pdf |
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| Bourles, Yves. |
| The Pacific oyster (Crassostrea gigas) is a major cultivated shellfish resource in France, which represented a tumover of 220 millions € in 2000. Mass mortalities among this commercially important bivalve species are known in France since about 40 years, but have become a recun'ing obstacle for growers of oysters and a threaten for commercial production along the French Atlantic coast in the last 20 years. Since 2000, IFREMER is canying out a multidisciplinary program, MOREST, ta understand the problem of summer mortality, and possibly ta solve il. As part of the MOREST program, the present study focuses on the relationship between gametogenesis, metabo lism and mortality of 7-month, i.e. juvenil e, C. gigas. In April 2004, a total of 2250 oysters were... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Naissain; Mortalité estivale; Gamétogenèse; Bilan énergétique; Crassostrea gigas; Spot; Summer mortalities; Gametogenesis; Energy budget. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/00448/55961/57444.pdf |
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| Le Moullac, Gilles; Hui, Belinda; Vonau, Vincent; Levy, Peva; Cochard, Jean-claude. |
| Preliminary experiments allowed defining basic requirements of Pinctada margaritifera for somatic and gonadic growth in controlled conditions. This study was continued by observation of the gametogenesis at a cellular level. In April/May 2008, 125 oysters were conditioned for 30 days in 25 tubular tanks (30 L). Water was renewed 4 times/hour. A mixed (v:v) diet of Isochrysis galbana (T-Iso) and Chaetoceros gracilis was supplied continuously. A control batch of 125 oysters was maintained in trays in the lagoon. An initial sample of 30 individuals was made. Gonadic changes were first characterized using a gonadal development index (GDI) based on the ratio of the gonad area to the total visceral mass area on a sagittal section of the body. Histological... |
| Tipo: Text |
Palavras-chave: Pearl oyster; Reproduction; Gametogenesis; Broodstock. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00029/14010/11196.pdf |
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| Bernard, Ismael; De Kermoysan, Goulwen; Pouvreau, Stephane. |
| DEB theory can be used to obtain a detailed description of energy allocation in organisms and the control of this allocation by temperature and food concentration. In this study, we modified the model of Bourlès et al. (2009) developed for the Pacific oyster, Crassostrea gigas, to improve the description of reproductive effort. The model was amended in two ways: a new set of parameters was incorporated and a full description of gonad construction in spring was added, with a new state variable. The application of this model to a dataset for oyster growth measured in four bays over two years showed that this model better described reproductive effort, without modifying overall growth dynamics. We then explored the reproductive responses of oysters to their... |
| Tipo: Text |
Palavras-chave: DEB model; Crassostrea gigas; Gametogenesis; Reproductive effort; Spawning date; Functional response. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00059/17047/14606.pdf |
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| Burgeot, Thierry; Quirion, Sophie; Quiniou, Francoise; Knoery, Joel; Soletchnik, Patrick; Gagnaire, Beatrice; Renault, Tristan; Osada, M.; Geret, F.; Communal, P. Y.; Jadas-hecart, A.; Gagne, F.. |
| In the Atlantic French coast, significant mortalities were observed in oyster communities during gametogenesis. These deaths possibly result from the cumulative effects of various stressors such as seasonal temperature variations, pesticide application and the release of contaminants from the resuspension of sediments. A field survey, based on aquaculture conditions at 15 and 70 cm from the sediment bed with genetically-resistant (R) and -sensitive (S) lines, showed a stress condition. Significant weight loss was observed during May 14th through June 10th for both R and S lines. On one hand, the levels of the egg yolk vitellin in females were decreased at May 14th for both R and S lines. On the other hand, a significant increase in vitellin production was... |
| Tipo: Text |
Palavras-chave: Mortalities; Herbicides; Sediment; Biomarkers; Gametogenesis; Crassostrea gigas; Pacific oysters. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-3384.pdf |
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| Calvo, J.; Morriconi, E.; Orler, P.. |
| The theoretical aspects of reproductive strategies and life histories are analyzed. The gonadal structures and the main features of gametogenesis of bivalves and echinoids are described. Research on the reproductive characteristics and gametogenic cycles of the bivalve molluscs in the Argentinian littoral and the echinoid Loxechinus albus is reviewed. Special references to Mytilus edulis, Aulacomya ater, Brachidontes purpuratus, Aequipecten tehuelchus, Zygochlamys patagonica, Ostrea puelchana, Clausinella gayi, Protothaca antiqua, Eurhomalea exalbida and Mesodesma mactroides are made. Analysis of reproductive cycles includes histological and ponderal descriptions of gonadal variations. The main trend found is the partial and multiple spawning episodes.... |
| Tipo: Book Section |
Palavras-chave: Hermaphroditism; Gametogenesis; Life cycle; Marine molluscs; Reproduction; Reproductive cycle; Hermaphroditism; Gametogenesis; Life cycle; Reproduction; Http://aims.fao.org/aos/agrovoc/c_3571; Http://aims.fao.org/aos/agrovoc/c_27931; Http://aims.fao.org/aos/agrovoc/c_4317; Http://aims.fao.org/aos/agrovoc/c_6507. |
| Ano: 1998 |
URL: http://hdl.handle.net/1834/2581 |
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| Le Moullac, Gilles; Soyez, Claude; Sham-koua, Manaarii; Levy, Peva; Moriceau, Jacques; Vonau, Vincent; Maihota, Mayalen; Cochard, Jean-claude. |
| This study aimed to model the food intake of P. margaritifera in order to examine the relationship between food level and reproductive activity. The effect of microalgae concentration on ingestion rate and assimilation efficiency was studied over a broad concentration range, using a mixture of Isochrysis galbana and Chaetoceros gracilis. Reproductive effort was assessed using three microalgae concentrations of 0.5, 7 and 18 cell μL-1. Reproductive status was assessed by gonad development index (GDI) – the ratio of the gonad surface to the visceral mass surface – and histological analysis of the gonad based on the presence (continuous or discontinuous) or the absence of gonial cells (GC). Ingestion is a saturating function of seston concentration for... |
| Tipo: Text |
Palavras-chave: Pinctada margaritifera; Food level; Ingestion rate; Reproduction; Gametogenesis. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00050/16085/13562.pdf |
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| Enriquez-diaz, M.; Pouvreau, Stephane; Chavez-villalba, J.; Le Pennec, M.. |
| The progress of gametogenesis was studied in oysters Crassostrea gigas having the same origin (Tremblade), but cultured during 1 year in two distinctive French marine areas, the Baie des Veys and Marennes-Ol,ron. We assessed seasonal changes in the reproduction cycle on the basis of stereological techniques to estimate reproductive investment and measurement of gonad evolution area by quantitative histology. From a qualitative point of view, both oyster groups presented typical reproductive stages, but showed differential timing, in particular during the sequence of spawning and duration of the re-absorption stage. Oysters in Baie des Veys had a single partial spawning in August and a re-absorption stage that extended until winter. Oysters in... |
| Tipo: Text |
Palavras-chave: Stereology; Reproductive investment; Pacific oysters; Image analysis; Gametogenesis; Crassostrea gigas. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7300.pdf |
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| Pouvreau, Stephane; Gangnery, Aline; Tiapari, Jerome; Lagarde, Franck; Garnier, Matthieu; Bodoy, Alain. |
| The gametogenic cycle and the reproductive effort of the blacklip pearl oyster, Pinctada margaritifera, cultivated in Takapoto lagoon were studied for a 1-year period (March 1997-April 1998) by bimonthly observations of gonadal sections, dry tissue weights and gonadal index in a population of pearl oyster composed of three age-groups. pearl oysters attained sexual maturity in the end of their first year (height approximate to 40 mm), implying that P. margaritifera is a late-maturing species in comparison with other Pteriidae. This species was also confirmed to be a marked protandrous successive hermaphrodite in culture, with 100 % of males at first maturity and 75 % in older pearl oyster (height > 120 mm). The general pattern of gametogenic activity,... |
| Tipo: Text |
Palavras-chave: French Polynesia; Reproductive effort; Reproductive cycle; Tropical aquaculture; Gametogenesis; Blacklip pearl oyster; Polynésie française; Effort de reproduction; Cycle de reproduction; Aquaculture tropicale; Gamétogenèse; Huître perlière. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-1391.pdf |
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| Borges,Michela; Yokoyama,Leonardo Q; Amaral,Antonia C. Z.. |
| This study describes the gametogenic cycle of Ophioderma januarii Lütken, 1856, a common species of ophiuroid in Southeastern Brazil. The specimens were collected during the project "Biodiversidade Bêntica Marinha no Estado de São Paulo-BIOTA/FAPESP-Bentos Marinho" (Marine benthic biodiversity in the State of São Paulo-BIOTA/ Fapesp-Marine Benthos) which was conducted off the northern coast of the state of São Paulo. Specimens were captured monthly between February 2001 and December 2002. Due to the low number of individuals the monthly data was grouped in seasons (spring to winter). A total of 101 specimens were obtained: 33 in spring, 10 in summer, 23 in autumn, and 35 in winter. The gonads of eighty-eight individuals (45 females, 42 males, and one... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Gametogenesis; Ophiuroid; Recruitment. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702009000100018 |
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| Registros recuperados: 41 | |
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