Strong invasion of Mellah lagoon (South-Western Mediterranean) by the American blue crab Callinectes sapidus Rathbun, 1896

Based on our discussions with fishermen and analysis of catches from professional fishing, this work confirms the presence of the American blue crab Callinectes sapidus in the southwest Mediterranean and highlights its invasion of Mellah lagoon in Algeria. The number and frequency of occurrence of this species in fishing gear (up to 10 individuals per fyke net), the presence of juveniles and ovigerous females as well as its presence in the local market, show that it is well established. The possible impact of C. sapidus on the local environment and native species, and the prospects for its fishing exploitation are discussed in the light of the current knowledge. •The American blue crab Callinectes sapidus has reached the southwestern Mediterranean coasts.•C. sapidus is established in Mellah Lagoon in Algeria and is considered a threat by local fishermen.•This species would have arrived, either passively in the larval state or by active migration of the adults.•Fishery exploitation of C. sapidus in Mellah lagoon would be a good strategy to mitigate its possible effects on the ecosystem.