Abstract
The article presents the results of a study on the seasonal dynamics of the hydrochemical parameters of water under a combinedwater supply system at the trout farm ―Trout Kargaly‖ (Aktobe Region, Republic of Kazakhstan). The research was conducted throughout the year, covering autumn, winter, spring, and summer periods. The main hydrochemical parameters of water were analyzed from three sources: an artesian well, the Kargaly Reservoir, and fish-rearing ponds. Determination of hydrochemical indicators was carried out in accordance with the current methodological guidelines for fisheries water bodies. It was established that the quality of the water used meets the regulatory standards for reservoirs intended for fish breeding and rearing. The artesian water is characterized by a stable chemical composition, optimal pH values, hardness, and dissolved oxygen content, creating favorable conditions for the cultivation of rainbow trout (Oncorhynchus mykiss). Seasonal variations in ammonium and phosphate ion concentrations in pond water are associated with natural biological processes, temperature fluctuations, and the specifics of the combined water supply system. The observed increases in certain parameters do not exceed established limits and have no negative impact on the environment. The results confirm the environmental safety of the farm’s operation, the efficiency of the combined water supply system, and its importance for the sustainable development of aquaculture under continental climate conditions.