Comparative morphometry of wild and farmed gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) in Monastir Bay (Tunisia)

Gilthead seabream Sparus aurata Linnaeus, 1758 and European seabass Dicentrarchus labrax (Linnaeus, 1758) are among the most important commercial marine fish species along the Mediterranean for both aquaculture and fisheries. In this study, we used truss network system morphometric trait analysis to investigate morphological differences between wild and farmed populations of S. aurata and D. labrax from Tunisia's largest aquaculture production area, Monastir Bay. The morphometric results showed clear differences between wild and farmed fish, mainly in cranial and body regions, for both seabass and seabream. The results indicate the usefulness of Condition Factor, Cephalic Index and Relative Profile Index in discriminating the origin (i.e. wild or farmed) of seabass and seabream. In addition, morphometric image processing analysis revealed that most of the differences were located mainly in the head and back of the body for the seabass and at the anterior and posterior part of the body for seabream. Hence, it can be suggested that the methodology used in this study to identify fish origin through morphological differences between wild and farmed fish could be used to differentiate escaped fish from local stocks.