Summer Mortality of Pacific Oyster Crassostrea Gigas : The Morest Project.

Intro -- Contents -- Page de titre -- Acknowledgements -- Preface -- 1. Evaluation of summer mortality risk factors in shellfish farming ecosystems -- Introduction -- The thermal risk factor -- The pluviometric risk factor -- The trophic risk factor -- The sediment risk factor -- Discussion-conclusion -- 2. Mortality risks associated with physiological traits of oysters during reproduction -- Introduction -- Materials and methods -- Gametogenesis, nutrition and mortalities -- Metabolic needs in summer -- The use of reserves over the summer period -- Nutrition and energy balance during summer -- Immune deficiency in summer -- General conclusion -- 3. Oyster summer mortality risks associated with environmental stress -- Introduction -- Experimental stress studies -- Sources of disturbance and environmental stress examined with the 'bottom-rack' comparison model -- Conclusion -- 4. The genetic basis of summer mortality in Pacific oyster spat and potential for improving survival by selective breeding in France -- PART I. Study of the genetic basis of summer mortality resistance in juvenile Pacific oyster Crassostrea gigas over four generations of selection -- Introduction: context and objectives -- First generation: estimation of the genetic basis of spat survival in their first summer in the field -- Second generation: divergent selection for high and low survival of spat in their first summer in the field -- Third generation: repeatability of the response to divergent selection for high or low spat survival in the first summer and expression of the character in triploids -- Fourth generation: repeatability of response to selection -- Field survival performances in the second summer period -- Laboratory studies of spat survival performance and correlations with field data -- Discussion and prospects for future research.

PART II. Towards Gigas+, a selection program to improve summer survival of the Pacific oyster Crassostrea gigas in France -- A review of the use of selection methods for shellfish improvement worldwide -- Points for the creation of a collaborative selection program to improve oyster summer survival in France: Gigas+ -- Appendix: Summary list of Morest generations and batches studied -- 5. Phenotypic characteristics of 'R' and 'S' oyster lines, selected for resistance or susceptibility. to summer mortality -- Introduction -- Differences in gametogenesis and reproductive effort between R and S oysters -- Comparative energy balance of R and S oysters -- Defense capacities of R and S oysters -- Stress responses of R and S oysters -- Aneuploidy levels of R and S oysters -- R and S oyster responses to pathogenic agents -- Differential gene expression between R and S oysters and the identification of physiological functions conferring resistance to summer mortality -- General discussion and conclusion -- 6. Oyster summer mortality risks associated with pathogens -- Introduction -- Finding and identifying potential candidate pathogens -- Pathogenicity and conditions of expression of infection -- The search for bacterial virulence genes -- Pathogenic agents and risk definition -- Conclusion -- 7. Temperature as a risk factor in oyster summer mortality -- Introduction -- Oyster physiology -- The sediment and 19°C -- Genetics and temperature -- Pathogens and temperature -- General conclusion -- 8. A synthesis of the Morest project and recommendations for forecasting and managing oyster summer mortalities -- Introduction -- PART I. Analysis of summer mortality using an interaction model -- Seawater temperature -- Reproduction -- Oyster genetics -- Stress -- Conclusion on the risk factors of the interaction model -- PART II. Risk management.

Temperature risk -- Reduction of mortality risks in the first year (first summer) -- Reduction of mortality risks in the second year (second summer) -- Exploitation of genetic variability -- Discussion and conclusion -- PART III. Risk forecasting methods -- Forecasting risk timing -- Forecasting the scale of mortality risk -- Discussion and conclusion -- References.

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Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, 2024. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries.