author(s)
Nour El Houda Boudemagh, Fatiha Bendali-Saoudi and Noureddine Soltani

abstract
In this work, we examined the biodiversity of water mites collected at the region of Collo (North-east Algeria). Sampling was carried out for a period of three years (2011/2012/2013). The species have been determined according to the keys of Soar & Williamson (1929), Viets (1930; 1936; 1956) and Marshall (1928). Five species belonging to three families (Eylaidae, Hydrachnidae, Hydryphantidae) and three genera (Eylais, Hydrachna and Eupatra), were revealed: two species belonging to the family of Eylaidae (Eylais hamata Koenike 1897, Eylais galeata Viets 1911), two species belonging to the family of Hydrachnidae (Hydrachna Murati Walter 1939, Hydrachna globosa De Geer 1778), and one species belonging to the family of Hydryphantidae (Eupatra rotunda Piersig 1906). However, The characterization of the structures of the water mite stand was performed using the ecological indices and showed a remarkable predominance of the species Eylais hamata, the other species are very rare.