Population-ecological analysis of Aral roach (Rutilus rutilus aralensis) was conducted in Tuzkan lake of Aydar-Arnasay lake system in Uzbekistan. In the Aydar-Arnasay lake system, it was analyzed the age structure, body weight, 19 morphometric and 5 meristematic indicators of 158 fish specimens caught in Tuzkan Lake in January and February 2020. The main selected indicators as a result of statistical analysis are: arithmetic mean; error rate; indicators of variability of morphometric and morpho-physiological signs; and variable asymmetry of meristem indicators. Statistical evaluation was conducted to determine the reliability of the survey results. Some features of the morpho-physiological state of the studied population were identified, which were explained by natural-climatic features, as well as anthropogenic impact on the water basin.