Genetic diversity, population structure and demographic history of the rock oyster Striostrea prismatica (Gray, 1825) within two Eastern Pacific biogeographic realms

Abstract

Context Striostrea prismatica is a valuable native oyster found along the Eastern Pacific coast from Mexico to Peru. There is evidence of overexploitation of this natural resource. Thus, population genetic data can help in designing management strategies. Aims This study aimed to assess the genetic diversity, population structure and demographic history of S. prismatica using nuclear and mitochondrial DNA markers. Methods Oysters were collected from seven natural fishing banks in two biogeographic realms of the eastern Pacific Ocean. Inter-simple sequence repeat markers and partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI), 12S rRNA (12S) and 16S rRNA (16S) genes were amplified by polymerase chain reaction and analysed. Key results Nuclear data revealed high intraspecific genetic diversity, moderate to strong genetic differentiation among fishing banks and a subtle genetic structure among marine ecoregions. The analyses supported strong isolation by distance, but chaotic genetic patchiness was also detected. Mitochondrial data showed high haplotype diversity and evidence of a population expansion c. 25,000 years ago. Conclusions Dispersal capacity, oceanographic features and historical factors can explain the levels of genetic diversity and the pattern of population differentiation and connectivity observed in S. prismatica. Implications The information generated in this study will support future management plans for this fishing resource.