Author(s): Nertila Muçollari1
  • 1. Faculty of Biotechnology and Food, Agricultural University of Tirana, Koder Kamza, Tirana 1000, Albania

Abstract: The River Vjosa is a 270 km long, large river which has its origin in the Pindos mountains in northern Greece and except for the first 10 km, this system is free flowing and not constrained by any longitudinal barriers. From the Albanian border downstream, where the Sarandoporos a major tributary enters, the river is referred to as Vjosa. In the region of Permet, the river shows an incisioned channel pattern, as sediment erosion exceeds sediment deposition, and it immerses into alluvial sediments. From this point on the river’scourse is characterized by large, braided sections alternating with constrained riverbeds and gorges wherever the river breaks through major geological barriers. Fish species constituite the major biodiversity component which is depending on dynamic and structure of habitatas within Vjosa itself. As of recent knowledge there are 30 fish species described for the Vjosa, of which 17 are freshwater species, seven are saltwater species, four show anadromous behavior,one namely Anguilla anguilla, is catadromous and for one species (Atherina boyeri) amphidromous behaviour is described. Apart from records of four alien species the Vjosa shows a high level of endemicity with nine of 26 native species (35 percent) being endemic to the Balcans. This fact is also represented in the conservation status of the fish fauna. According to the national Albanian red list three species are endangered (Acipenser naccarii, Acipenser sturio, and Asphanius fasciatus) and two vulnerable (Petromyzon marinus and Platychthis flesus). IUCN considers three species to be critically endangered (Acipenser naccarii, Acipenser sturio and Anguilla Anguilla) and additionally Gobio skadarensis is categorized as endangered. The Bern convention lists three species in Annex Ⅱ (strictly protected fauna species) (Acipenser naccarii, Acipenser sturio and Asphanius fasciatus) and two as in Annex Ⅲ (Alburnoides aff. Prespensis, Chondrostoma vardarense, Pachychlion pictum and Petromyzon marinus). There is a severe lack of knowledge concerning these systemscompared to other systems in Europe, resulting in limited available data information about these species and their population status. This means that more species than previously thought could be severely threatened.