First Scientific Records of the Invasive Red Swamp Crayfish, Procambarus clarkii (Girard, 1852) (Crustacea: Cambaridae) in Malta, a Threat to Fragile Freshwater Habitats.

This study reports the first records of the invasive fresh water red swamp crayfish, Procambarus clarkii in Malta, first spotted in the wild in summer 2016. In spring 2017, 26 specimens of P. clarkii were collected, sexed, measured and identified both morphologically and genetically. The distribution and density of the species along the same valley were investigated at Fiddien Valley and Chadwick Lakes. As these two locations are associated with one of the major valley systems that cross the island, the presence of this prolific, aggressive and opportunistic feeding crayfish species increases the vulnerability of native freshwater species.