The Distribution and Ecological Preferences of Stone Crayfish Austropotamobius Torrentium (Schrank, 1803) (Decapoda: Astacidae) in the Northwest Romania

Abstract

This paper presents data on geographical distribution and ecological preferences of Austropotamobius torrentium species following investigations of 104 sampling sites in the west and north-western Romania. Specimens were caught by actively searching the river bed, after which they were released. A detailed map of the distribution was prepared: the species was found to be living in 23 sampling sites from three basins: Crişul Alb, Crişul Negru and Crişul Repede. The current distribution of the species extends to the central and eastern part of the Codru Moma Mountains, western Bihor Mountains, eastern Pădurea Craiului Mountains, central and northern areas of the Vlădeasa Mountains and southern and central areas of the Plopiş Mountains. The northernmost population of Romania is found in the Valea Mare River, on the Plopiş Mountains. Generally, the species occurs on a substrate consisting primarily of stone and gravel. The species’ preferred combination of riparian vegetation is Alnus sp. and Salix sp. in deciduous forests. An important number of investigated rivers, totalling 37, are occupied by the Astacus astacus species, data proving that there are no mixed populations. No other non-indigenous crayfish species were found during this study.