EXAMINING THE GENETIC BASIS AND PHYSIOLOGY OF SURVIVAL IN EXTREME LOW SALINITY TO IMPROVE AQUACULTURE OF THE EASTERN OYSTER Crassostrea virginica

dc.contributor.advisorPlough, Louisen_US
dc.contributor.authorMcCarty, Alexandra Jen_US
dc.contributor.departmentMarine-Estuarine-Environmental Sciencesen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2022-06-15T05:36:29Z
dc.date.available2022-06-15T05:36:29Z
dc.date.issued2022en_US
dc.description.abstractThe eastern oyster, Crassostrea virginica, is an important aquaculture species and supports a growing industry along the east coast of the United States. However, increases in freshwater from storm events and intentional diversions can expose coastal aquaculture operations to extreme low salinity (< 5), resulting in reduced productivity and mortality. The primary objectives of this dissertation were to investigate the biology and genetic basis of low salinity tolerance to improve eastern oyster aquaculture. In Chapter 2, I developed and conducted a series of extreme low salinity (2.5) challenges to estimate the quantitative genetic parameters of low salinity survival. A moderate narrow-sense heritability was estimated for challenge survival, h2 ≈ 0.4. In addition, osmolality of hemolymph collected from oysters during the first week of the challenge suggest that all individuals conformed to the surrounding low salinity regardless of challenge survival. In Chapter 3, I performed additional low salinity challenges to assess the importance of challenge duration (2 or 6 months) and temperature (chronic or fluctuating) on low salinity survival. I also investigated algae removal during the chronic challenge to better understand oyster response during low salinity stress. Phenotypic (rS = 0.89) and genetic (rG = 0.81) correlations between family mortality were high across the two challenges, indicating that a 30-day exposure at a constant low salinity (2.5) and temperature (27°C) is a sufficient progeny test for low salinity survival. Modest associations between algae removal metrics and survival in extreme low salinity indicate that individual feeding ability may relate to differential low salinity survival. Lastly, in Chapter 4, I performed genome mapping to investigate the genomic architecture of low salinity survival. Quantitative trait locus mapping and linkage disequilibrium analysis revealed a significant region on eastern oyster chromosome 1 and 7. Genomic prediction accuracies for survival and day to death in extreme low salinity were moderate and encouraging, 0.49 – 0.57. The results from my dissertation characterize the genetic basis of survival during low salinity events and support the incorporation of this trait into breeding efforts to improve production and enhance the resiliency of the eastern oyster aquaculture industry.en_US
dc.identifierhttps://doi.org/10.13016/k47f-dget
dc.identifier.urihttp://hdl.handle.net/1903/28725
dc.language.isoenen_US
dc.subject.pqcontrolledGeneticsen_US
dc.subject.pqcontrolledAnimal sciencesen_US
dc.subject.pqcontrolledBiologyen_US
dc.subject.pquncontrolledBreedingen_US
dc.subject.pquncontrolledEastern oysteren_US
dc.subject.pquncontrolledGenomic selectionen_US
dc.subject.pquncontrolledLow salinity stressen_US
dc.subject.pquncontrolledPhysiologyen_US
dc.subject.pquncontrolledQuantitative geneticsen_US
dc.titleEXAMINING THE GENETIC BASIS AND PHYSIOLOGY OF SURVIVAL IN EXTREME LOW SALINITY TO IMPROVE AQUACULTURE OF THE EASTERN OYSTER Crassostrea virginicaen_US
dc.typeDissertationen_US

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