Slovenia Post have issued the local WWF first day cover along with the launched the stamp series of Stone crayfish (Austropotamobious torrentium) on September 23, 2011. The First Day Cover has image of this species on the left-bottom side . The issued of four postage stamps has placed on the top rows of FDC and cancelled with postmark of WWF logo.
The stone crayfish is a member of the order Decapoda, or ten-legged crustaceans. Three species of crayfish live in fresh water in Slovenia: the noble crayfish, the stone crayfish and white-clawed crayfish.
The stone crayfish (Austropotamobius torrentium) is smaller than the noble crayfish. It grows up to 10 cm and lives primarily in small streams and also at higher elevations. It lives in streams that have mainly rocky beds, where it hides beneath the rocks. Its carapace is usually brown, and the underside of the claws is lighter and never red as are those of the noble crayfish. Its range extends throughout central and southern Europe.
In Slovenia it is widespread mainly in the Sava and Drava watersheds, and is less present in the Primorska and Pomurje regions. Due to its small size it was never very interesting economically and was never bred or used as a food source.
Due to the regulation of watercourses and water pollution, all of these crayfish species are highly threatened and therefore also protected. Natura 2000 protection areas have been established in order to protect the stone crayfish.