Spatial variability of the reproductive traits of Rajidae family (Elasmobranchii, Rajiformes) across the Italian waters

Examination of the life-history traits variability along geographic patterns represents an important issue for elucidating intra-specific biological features in populations geographically separated and representing useful data to better ascertain potential stock boundaries. In this study, some biological and reproducitve traits of three Rajids Raja asterias, R. clavata and R. miraletus from four Italian Geographic SubAreas were compared. Results showed differences in population structures of males/females and immatures/matures and in the size at sexual maturity (L-50), mainly in R. asterias. The latter displayed also relevant differences in reproductive traits of males and females caught in the South Adriatic with those of the other investigated areas. R. clavata and R. miraletus showed less significant differences in L-50 among all studied areas, as well as in the morphometric trends of the reproductive organs in relation to the size. The comparison of biological traits among populations may represent a promising approach for improving the knowledge on ecological and spatial variability of the elasmobranchs, and therefore for updating the Action Plan data for the Conservation of Cartilaginous Fishes in the Mediterranean Sea.