Crayfish in Italy: distribution, threats and management

Document Type : Review


Department of Evolutionary Biology “Leo Pardi”, University of Florence, Via Romana 17, 50125 Florence, Italy


Many populations of indigenous crayfish species (ICS) are at serious risk of extinction in Italy due to the growing number of threats to their integrity. These mostly derive from various forms of anthropogenic pressure, dramatically increased in the last 50 years. The distribution of the most widespread ICS in Italy, Austropotamobius pallipes, is noticeably smaller than in the last century and the number of A. torrentium and Astacus astacus populations is today small. On the contrary, Italy has been invaded by several non-indigenous crayfish species (NICS), particularly the North American Procambarus clarkii, Orconectes limosus, and Pacifastacus leniusculus. The distribution of a fourth NICS, the Ponto-Caspian Astacus leptodactylus, is still limited, probably due to its susceptibility to the oomycete Aphanomyces astaci, whereas the marbled crayfish, Procambarus sp., and the Australian Cherax destructor have already appeared in the wild. Any intervention aimed at the conservation of ICS should rely on a broad-spectrum actions; in any case, a crucial step will be to restore and maintain the integrity of the natural habitats that will be accomplished also by reducing environmental stresses, including those induced by NICS. The management of crayfish populations require guidelines firmly based on the growing body of scientific knowledge on the biology and ecology of the target species. Finally, special attention should be paid to informing, educating, and raising awareness among non-specialists, whose support and participation are essential prerequisites for the success of any intervention.