Confirmation of the presence of Squalius squalus (Bonaparte, 1837) in Sicily.

ANTONINO DUCHI , Monica Giampiccolo

The occurrence of the Italian chub Squalius squalus (Bonaparte, 1837) in Sicily has always been reported in the literature in a contradictory manner and without certain documentation, being regarded as doubtful by the most recent reviews of the xenodiversity of Sicilian inland waters. Recently, the DNA of the species was detected in an artificial lake. Here we report the first confirmed record of the species in a Sicilian river environment, the Oreto, at two sites close to the mouth sampled by electrofishing in June 2026. The specimens (87–350 mm TL; 7–486 g) were identified as S. squalus on the basis of morphometric and meristic characters compared with the reference literature. The two largest individuals were males in reproductive condition. Anguilla anguilla, Cyprinus carpio, Sarmarutilus rubilio, Salariopsis fluviatilis and Chelon labrosus were also present in the study area. The Italian chub thus joins the list of alien species occurring in Sicilian freshwaters, bringing to 13 the number of alien fish species recorded on the island. Since neither the origin nor the period of introduction is known, a release for recreational fishing purposes is hypothesized, with artificial lakes as likely sources of invasion. The finding a few kilometres from the river mouth testifies to the marked adaptability of the species and to the presence of suitable habitats for this rheophilic cyprinid in the terminal stretch of Oreto. Further investigations are needed to define its distribution in Sicily and its possible interference with native species or species of conservation concern.