ABUNDANCE OF RARE FISH SPECIES OF THE YUZHNY UZYAN RIVER OF THE BASHKIR NATURE RESERVE

Climatic factors inherent in the period from 2008 to the present have directly influenced the behavior and dy- namics of the ichthyofauna of the Bashkir Reserve. Migrations and altitude preferences, trends in the abundance of groupings are an additional characteristic of the habitat of groups of rare fish species and explain the strategy of their survival in the period of unfavorable conditions. Studies of the state of the number and preference of habitats by alti- tude of rare species of the main watercourse of the Bashkir Reserve – the Yuzhny Uzyan River in 2013–2017 re- vealed that there is a movement of herds by altitude level. Thymallus thymallus in the conditions of the mountain- forest zone has a positive tendency in abundance, and in the Cottus gobio, on the contrary, a negative one.