Black Mouth Croaker (Atrobucca nibe) is of significant value from the economics point of view. In the following study, the genetic diversity of Atrobucca nibe has been investigated using the PCR-sequencing method from three different regions of the Persian gulf and Oman Sea, namely Chabahar in the Sistan and Baluchestan and Jask in Hormozgan Province of Iran and Fujairah in the Fujairah Emirate of the United Arab of Emirates. The purpose of the following exploration has essentially beencoined to further the study of Atrobucca nibe genetic diversity and its population structure in the Persian Gulf and Oman Sea. For this purpose, a number of 54 fish have been collected from the aforementioned regions. The DNA of the fish had been extracted through the Ammonium Acetate method and the quality of the DNAs were analyzed via the spectrophotometry and furthermore the quantity of the extracted DNA were assessed viaelectrophoresis. Polymerase Chain Reaction (PCR) was conducted on the targeted DNAs and thenceforth DNA sequencing was carried out. Subsequently, through sequencing it was discovered that the D-loop region in the mitochondrial DNA (mtDNA) of Black Mouth Croaker,contained 270 base pairs (bp). For the purpose of analyzing the genetic diversity of Atrobucca nibe and its population structure in the Persian Gulf and Oman Sea, the following softwares have been conducted, namely theBioEdit, Arlequin, Dnasp and Mega5 software. Furthermore, the Kimura 2-parameter was used for the purpose of genetic distance analysis. Through observations of average levels of FST between the regions, it can be summed up that genetic differences do exist among the present populations. On the grounds of the obtained results from the Persian Gulf and Oman Sea, it can be concluded that there currently are three different populations of Atrobucca nibe residing in the waters of Sistan & Baluchestan, Hormozgan and Fujairah
