The Spiny-cheek Crayfish Faxonius limosus (Rafinesque, 1817) (Decapoda: Cambaridae) Invades New Areas in Serbian Inland Waters

Faxonius limosus (formerly known as Orconectes limosus in the literature) is an invasive alien crayfish species with the largest distribution range in Europe. The first record of this species from the Danube River in Serbia was near Apatin in 2002, and since then it has expanded its range along the entire Serbian section. The presence of F. limosus was studied during a twelve-year period (2007-2019), covering different types of water bodies in Serbia (rivers, canals, lakes, reservoirs and ponds). The species was detected at seven new localities along the main course of the Danube River, denoting that its colonisation has developed in two directions, upstream and downstream, respectively. Along with its expansion in the Danube River, the occurrence of F. limosus has been recorded in all main tributaries. the rivers Sava, Tisa and Velika Morava, as well as the Danube-Tisa-Danube Canal (DTD Canal). Due to its rapid dispersal rate and negative effect on native crayfish species, urgent measures are needed to monitor and prevent further spread of this invasive alien species in the Serbian inland waters and the Danube River Basin.