The eastern oyster (Crassostrea virginica ) is one of the most ecologically and economically valuable species in Texas and the United States . The Texas oyster fishery has experienced an overall decline over the last two decades, and in an effort to revitalize the industry, the state of Texas passed a law in 2019, making commercial aquaculture of oysters legal in state waters for the first time. Previous research has identified three genetic groups in the Gulf of Mexico (hereafter Gulf) : a s outhern population that is only present in Texas, a n orthern population that extends eastward across the Gulf, and an eastern population in Florida. In Texas, both northern and southern populations naturally co-occur in a transition zone near Aransas Bay. An understanding of fine-scale population structure across the Gulf is needed to inform appropriate management strategies for the aquaculture industry, commercial fishery, and restoration efforts .
Double digest restriction-site associated DNA sequencing was used to genotype 451 individuals collected from Texas to Florida (Fig. 1) . Preliminary analysis found similar patterns of genetic structure in the Gulf as previous research , and admixed individuals were identified within all regions . In Texas, re-assessment of the transition zone indicated a slight southern movement towards Corpus Christi Bay. Results of this study suggest long-term monitoring of the northern/southern transition zone may be needed for appropriate mariculture management in Texas .