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| Maurer, Daniele; Comps, Michel; His, Edouard. |
| Summer mortalities in the Pacific oyster in the Bay of Arcachon were analysed during four years (1981 to 1984). Mortalities occur mostly among one year old oyster and affect the whole bay, with different prevalence. The phenomenon occurs at certain times during the summer spawning period and is associated with high temperatures. A thinning of the digestive tubule epithelium is observed, but there is no evidence of infectious disease. The failure to find a causative agent, pollution or pathogen, tends to strengthen a physiological disorder hypothesis, related to environmental conditions. The influence of external (temperature, available food) and internai factors (length, maturation, spawning) on this phenomenon is discussed. A comparaison is drawn with... |
| Tipo: Text |
Palavras-chave: Bay of Arcachon; Summer mortalities; Crassostrea gigas; Bassin d'Arcachon; Mortalités estivales; Crassostrea gigas. |
| Ano: 1986 |
URL: http://archimer.ifremer.fr/doc/1986/publication-4318.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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| Engelsma, M; Roozenburg, I; Joly, Jean-pierre. |
| In summer 2006 an extensive mortality of Pacific oysters Crassostrea gigas occurred in Lake Grevelingen, the Netherlands. A sample of Pacific oysters was investigated for the presence of shellfish pathogens as potential causes of the mortality. Yellow-green lesions were observed in several oysters upon clinical inspection. Histopathology showed that 6 out of 36 oysters had a suspected bacterial infection, including 4 Nocardia-like infections. Two bacterial species, Vibrio aestuarianus and Nocardia crassostreae, were isolated from haemolymph samples and identified using PCR and sequencing of the 16S rRNA gene. This is the first isolation of N. crassostreae from shellfish in European waters. The near full-length 16S rRNA sequence of this Dutch Nocardia sp.... |
| Tipo: Text |
Palavras-chave: Summer mortalities; Ostrea edulis; Crassostrea gigas; Vibrio aestuarianus; Nocardia crassostreae. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4568.pdf |
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| Garnier, Matthieu; Labreuche, Yannick; Nicolas, Jean-louis. |
| Eleven Vibrio isolates invading the hemolymph of live and moribund oysters (Crassostrea gigas) collected in the field and from a hatchery in France, were characterized by a polyphasic approach. Phylogenetic analysis of 16S rRNA, gyrB and toxR genes indicated high homogeneity between these strains and the Vibrio aestuarianus type strain (ATCC35048(T)), and confirmed previous 16S rRNA analysis. In contrast, DNA:DNA hybridization was from 61% to 100%, while phenotypic characters and virulence tests showed a large diversity between the strains. Nevertheless, several common characters allowed the isolates to be distinguished from the reference strain. On the basis of several distinct phenotypic characteristics, it is proposed to establish two subspecies within... |
| Tipo: Text |
Palavras-chave: Polyphasic approach; Summer mortalities; Crassostrea gigas; Pathogen; French isolates; Vibrio aestuarianus. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4961.pdf |
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