This paper describes the attempts to protect and re-establish threatened populations
of the native freshwater crayfish, Austropotamobius pallipes, of Navarra, Spain. Three species of crayfish are presently thriving in Navarra, the native species A. pallipes and the introduced
North American species Pacifastacus leniusculus and Procambarus clarkii . Both species
are known to carry the fungus Aphanomyces astaci in their cuticles and to transmite it to
the native species. The management strategies implemented by the authorities in order to
restore native populations of crayfish are discussed
