In 2020 - 2021, research of state of commercial fish stocks and the volume of permissible fish capturing in the Aydar-Arnasay lake system in Uzbekistan (the middle reaches of the Syrdarya River) has been conducted. The data on the coefficients of loss, natural and commercial mortality of fish and statistical data on catches by species are given. The total ichthyomass of the commercial fish species mature part of the populations in the system of lakes is about 20 - 21 thousand tons in total (without species separation). The number of fish that can be captured without damage (total commercial stock) in these years is about 7 - 7.5 thousand tons. At present, the main commercial fishes are roach (Rutilus rutilus), pike perch (Sander lucioperca) and common carp (Cyprinus carpio), in some years there may be noticeable catches of gibel carp (Carassius gibelio).