Materials to the biology and modern condition of the essential and rare species of the fishes in the Irtysh river

Abstract

This article deals with the materials of the biology and ecology valuable sorts rare fishes of the Irtysh basin, such as sterlet – Acipenser ruthenus, siberian sturgeon – Acipenser baeri, and also usual taimen Hucho taimen and inconny (population zaisan) – Stenodus leucichthys. The supervisions of the last years show the decline of measuring-gravimetric indexes of sterlet, increase of being in the catches of young of sturgeon and inconny. The analysis shows that despite of some growth of the sturgeons, , their quantity and natural habitat grew short and continue to diminis, the condition of the populations causes definite concerns and demands special measures of protection.