Date of Award

Summer 6-2023

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)


Ocean Science and Engineering

Committee Chair

Eric Saillant

Committee Chair School

Ocean Science and Engineering

Committee Member 2

Eric Powell

Committee Member 2 School

Ocean Science and Engineering

Committee Member 3

William Walton


The decline of natural oyster reefs in Gulf of Mexico (Gulf) states has stimulated the development of aquaculture to support the industry and restoration programs. Gulf habitats feature diverse salinity environments that may require oysters bred for habitat-specific optimal genetic characteristics. In this work, genetic parameters for performance in habitats with different salinity were estimated. In September 2020, 102 males and 102 females sourced from 17 natural reefs across the northern Gulf were bred according to 2 males x 2 females non-overlapping factorial crossing designs, resulting in 204 full and half sibs. All families were pooled after fertilization according to the common garden principle. The 204 founders and offspring sampled at different times during culture were assayed at 192 Single Nucleotide Polymorphism markers and the obtained genotypes were used to assign offspring to parent pairs using a likelihood ratio approach. Three low-salinity sites and one high-salinity site were harvested and analyzed. Family distributions differed between the high-salinity group that experienced 66% mortality and the three low-salinity groups where mortality was between 7 and 22%, supporting separate breeding for performance in high and low salinity environments. The number of dams and sires contributing to harvested offspring ranged between 133 and 151, indicating that a large fraction of the initial breeding design was recovered. Heritability of height was intermediate in all groups (range 0.38 – 0.84) and genetic correlations across environments were also relatively high (0.62-0.99, average 0.77) suggesting genotype x environment interactions for growth are moderate.

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