Morphological analysis of pectoral fin spine for identifying ecophenotypic variation of Persian Sturgeon Acipenser persicus

One goal of fisheries management is to identify stocks and ecophenotypics of individual specimens correctly. Discrimination of Persian sturgeon Acipenser persicus ecophenotypics due to geographic variation was attempted based on calcified anatomical structures. Morphological characteristics of the pectoral fin spine were analysed in stocks from the eastern and western parts of the south Caspian Sea to explore if polymorphism could be discerned between regions within the Caspian Sea using ten key features which were measured. These key features were measured and used for multivariate analysis. Principal component analysis (PCA), discriminant function analysis and cluster analysis were used to visualize differences between regions, to follow any shape differences in the spines and to classify into the groups. On the basis of morphometrics between spines, 82.9% of the individuals were correctly classified into one of the two regions. PCA showed the largest differences between the eastern and western regions were the density and arch of pectoral fin spine. Fish from the eastern region had a heavier and more curved pectoral fin spine when compared to those from the western part. The results from this study indicate that the morphological traits of pectoral fin spine of the Persian sturgeons can be used to discriminate between regions with a reliability rate of about 83%. Therefore, the morphological differences are discernible in spite of the volume of artificial rearing and release of fish in the south.