Review of the state of knowledge of crayfish species in the Iberian PeninsulaThis paper reviews information relevant to managing the four crayfish species present in the Iberian Peninsula. The red swamp crayfish, Procambarus clarkii, signal crayfish, Pacifastacus leniusculus, and Yabbie, Cherax destructor, are classified as invasive alien species by Spanish legislation. The most significant negative impacts of these species in freshwater ecosystems are noted, and some management methods are proposed. In addition, scientific studies addressing the origin and taxonomy of the Iberian white-clawed crayfish, Austropotamobius italicus italicus, are discussed. The Iberian populations of A. i. italicus have been severely diminished since the onset of the expansion of the aphanomycosis disease in 1978. However, this trend began to undergo reversal a few years ago, and the populations of this species are now growing. Finally, current legislation concerning the fishing and conservation of crayfish species is explained and discussed.