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| Broquard, Coralie. |
| Knowledge about the mode of reproduction and the sex determination of the cupped oyster Crassostrea gigas remains limited. As a sequential hermaphroditic species, sex determination takes place several times during its lifetime. As part of this thesis, the sexual phenotypes of the first 6 years of life of oysters were identified in two cohorts. Thus, the sex ratio was biased towards females from the first sexual maturity, as well as for all subsequent years. After six years of sexing, 42%, 32%, 19%, 5%, 1% and 0.1% of oysters showed 0, 1, 2, 2, 3, 4 and 5 sex changes. The frequency of sex changes also decreased with age (34% between years 1-2 to 9% between years 5-6). This thesis work has also sought to determine the influence of sex and sex change on the... |
| Tipo: Text |
Palavras-chave: Déterminisme sexuel; Facteurs moléculaires; Sex determination; Hermaphroditism; Growth; Molecular factors; C. gigas. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00692/80422/83558.pdf |
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| Lassus, Patrick; Bardouil, Michele; Masselin, Pierre; Naviner, Magali; Truquet, Philippe. |
| A sea water recirculating flume was especially designed in the framework of this study. It improves physiological and ecophysiological evaluation of a 25 oysters (c. gigas) set fed on PSP toxic A. minutum cultures and then detoxified with commonly used aquaculture species (I. galbana, T. suecica, S. costatum, T. weissflogii). Chlorophyll a levels are kept steady in each case and adjusted in order to reach the same food value in each tank (0,5 mg/l TPM). When exposed to the mildly toxic species A. minutum (0,5 pg.eq.STX.cel-1) oysters depict a reduced clearance rate, food uptake and shell-valves activity (compared to non-toxic algal diets). The same physiological parameters do not show any significant differences when oysters are exposed to the control al... |
| Tipo: Text |
Palavras-chave: Épuration; Crassostrea gigas; Alexandrium minutum; PSP; Écophysiologie; Depuration; C. gigas; A. minutum; PSP; Ecophysiology. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00139/25021/23126.pdf |
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| Soletchnik, Patrick; Polsenaere, Pierre; Le Moine, Olivier. |
| Historiquement, les pêches de larves de l’huître creuse (C. gigas) ont lieu en six stations du BMO depuis les années 70, de début juin à la première semaine de septembre. La comparaison des captures saisonnières et hebdomadaires entre les périodes P1 (1977-1991) et P2 (2000-2015) montre un ajustement de la distribution des captures de larves à un modèle polynomiale d’ordre 4 pour P1 (R2 = 0,77), puis d’ordre 2 pour P2 (R2 = 0,86). Les modèles de distribution des captures montrent que la saison de reproduction a doublé entre les deux périodes. Elle s’étend aujourd’hui de juin à septembre. Devant l’extension de la saison de reproduction, la saison de pêche expérimentale est aujourd’hui trop réduite. Toutefois, le pic d’abondance des captures n’a pas changé... |
| Tipo: Text |
Palavras-chave: Huître; C. gigas; Changement global; Réchauffement climatique; Reproduction; Larve; Mortalité; Phénologie; Ostréiculture; Bassin de Marennes Oléron; Phytoplancton; Chlorophylle a; Température. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00441/55239/56723.pdf |
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