The decline of natural reefs of the eastern oyster (Crassostrea virginica ) in the northern Gulf of Mexico (Gulf) has stimulated the development of aquaculture to support the market demand and restoration programs. Gulf habitats feature diverse salinity environments that may require oysters bred for habitat-specific optimal genetic characteristics. Here, we report the performance of eastern oyster bred in low-salinity environments after one generation of selection.
Selective breeding employed a common-garden approach where families were pooled at fertilization for communal rearing and molecular pedigrees were used a posteriori to determine parentage and estimate breeding values in a walk-back selection process. The F1 generation pool was bred in 2020 and included 202 full and half-sib families that were deployed on three low salinity sites for growth challenge. Breeding values (BV) for height were estimated at harvest size in fall 2021. Parents with highest BVs were bred in 2022 to generate 102 full sibs and 51 half sib families with a selection differential of +3.10 mm (5.7%). A control pool was also generated using 25 full sib families with BV’ s averaging +0.089 mm. The F2 generation (selected and controls) was reared at the Grand Bay Oyster Park and Mobile Bay site, where growth and survival were monitored via bi-monthly sampling . Selected oysters had significantly greater survival at peak mortality (Fig. 1) and shell height 10-months post deployment (Fig. 2) than control oysters at both sites, indicating positive response on growth and correlated increase in survival.