The return of the Blue Crab, Callinectes sapidus Rathbun, 1896, after 70 years from its first appearance in the Gulf of Trieste, northern Adriatic Sea, Italy (Decapoda: Portunidae)

Since August 2015, an increasing number of Blue Crabs, Callinectes sapidus Rathbun, 1896, have been reported in the Marano and Grado Lagoon, Gulf of Trieste, in the northern Adriatic Sea. This species is not a new introduction and in fact the first record of C. sapidus in Italy and the entire Adriatic Sea dates back to 1949 in the Grado Lagoon. Interestingly, no other records of C. sapidus have been reported since the first record. Here, we note the re-appearance of C. sapidus in the Gulf of Trieste.