Before the lowering of water level of the lake Sevan the annual fish hunting consisted almost equally of trout and carp (accordingly 50 % and 40 %). In this time period the portion of whitefish in annual hunt portion was 0.29%. In the initial period of water level lowering of the lake (1939-1962), because of the artificial increase of the watercourse of the river Hrazdan, the morphometric and hydrodynamic indices, temperature regime of the lake Sevan were ...