Discrimination of Red Mullet Populations (Teleostean, Mullidae) Off the Sicilian Coasts (Mediterranean Sea) on the Basis of Metazoan Parasites

Knowledge on fish stock units and their boundaries is still poor in the Mediterranean despite the relevance of this information for developing accurate stock assessment and effectivelymanaging fisheries. The aim of this work is to identify parasite species that might serve as biological tags for discrimination of redmullet stocks Mullus barbatus and M. surmuletus, off the northern and southern coasts of Sicily (central Mediterranean). Stephanostomum sp. metacercariae were selected as good biological tags for M. barbatus and M. surmuletus. Specimens caught in the Strait of Sicily showed a high level of metacercariae infections while no infected fish was found in the Southern Tyrrhenian Sea. Furthermore, cestode larvae (order Trypanorhyncha), and adult and larval digeneans were considered suitable as biological tags for stock discrimination in M. surmuletus, presenting statistically different epidemiological levels between the two areas. Results suggest a likely occurrence of distinct populations of red mullets in two areas of the central Mediterranean on the basis of parasite infestations.