The Ichthyofauna of Aghstev and Debed River Basins (North Armenia) and the Impact of Separate Factors on its Transformation

It is well known that Aghstev and Debed river basins (North Armenia) are not famous for their fish diversity. According to M. Dadikyan only 7 main species had inhabited in the above mentioned river basins until 70th of 20th century. Later, the studies conducted from 1990 to 2005 indicated that the fish diversity has completely changed: reaching up to 13. As a result the recent studies have shown that the quantity of fish species of rivers belonging to Aghstev and Debed river basins has increased up to 19. Since 1970 more than double growth of fish species diversity is conditioned by the fish species released in the rivers by amateur fisherman or imported fishes randomly falling into wild freshwaters from private small farms. It's worth mentioning that the quantity of local habitat fish species mainly valuable fish species (Salmo trutta, Salmo caspius, Capoeta capoeta, etc.) has reduced the reasons of which are banned poaching, the exploitation of small hydro power plant (SHPP), pollution of river water with household waste water and the usage for agricultural purposes.