Population Connectivity of Eastern Oysters in Texas and Its Implications for Management in the Gulf of Mexico

The eastern oyster, Crassostrea virginica, is a commercially and ecologically important species.  Past studies of population structure of this species indicate that at least some areas of Texas are differentiated from the eastern Gulf of Mexico; however, detailed studies of structure and connectivity along the Texas coast are lacking.  To address this issue, we examined amounts and distribution of genetic variation in eastern oyster using a 1149 bp region of the ND4 gene in the mitochondrial genome across the main bay systems in Texas.  We estimated haplotype diversity, nucleotide diversity, and population differentiation (φ_st) for 150 individuals.  Overall haplotype (haploid genotype) diversity was 0.95 and overall nucleotide diversity was 0.005.  Our results also indicate no differentiation among populations (φ_st=0.008, p = 0.11).  However, we found one haplotype unique to southern part of our study area.  We explore the distribution of this haplotype in Texas bays and consider the implications for population connectivity, management, and restoration.  Understanding population structure and connectivity of this species will inform management decisions, including harvest policies and oyster reef restoration.  Furthermore, this work provides a foundation for other studies examining ecological significance of genetic diversity.