Ecological aspects of using heat waste water of energy facilities for sturgeon (Acipenseridae) aquaculture

Purpose. To assess the temperature regime and chemical composition of water in the water supply system of the existing sturgeon farm created using the warm discharge water of the energy facility. Methodology. The main extent of the study on the determination of abiotic factors in the aquatic environment was carried out based on data collected during 2021–2024 in the conditions of industrial-type sturgeon farm “Biosila” LLC. Cultivation of sturgeons in the technological cycle of this enterprise is performed in tank’s conditions with the use of warm waste water from an energy facility. Control of water temperature and the dissolved oxygen content in water was carried out using thermometers for measurements in water and Oxy Guard® thermo-oximeter (PolarisC). Water temperature was measured three times a day (at 8, 15, and 20 hours) followed by determination of the average value. Hydrochemical studies were carried out according to methods generally accepted in aquaculture and hydrochemistry. The obtained results were compared with the normative values ​​of hydrochemical parameters for sturgeon farms existing in the aquaculture of Ukraine. Findings. During the 185–245-day growing seasons of 2021–2023 with a water temperature above 10°C, the average temperature values ​​of water in the tanks of “Biosila” LLC for the decades of March–November ranged from 10.0 to 32.0°C. In different years, temperature maxima on individual days of July, August, and September reached the level of 30.0–32.5°C, which was more than 5.0°C higher than similar values in water bodies from the region with the natural temperature regime of the Ukrainian Forest Steppe. The registered maximum values ​​of water temperature significantly exceeded the limit of favorable values ​​(25.0°C) for sturgeons. However, there were no cases of mass death of sturgeons during the entire study period. The dissolved oxygen content in tanks of “Biosila” LLC according to the average monthly values of the warmest period of the year (May-September) was in the range of 4.9–6.4 mg O2/dm3. The minimum values ​​of this parameter were 4.0–4.6 mg O2/dm3. Other hydrochemical parameters of tanks with sturgeons did not significantly exceed the limits of normative values ​​for sturgeon farms and were typical for fishery water bodies in the region. Originality. The temperature regime and the main hydrochemical parameters of the current sturgeon farm using the warm discharge water of the energy facility in the modern climatic conditions of the Ukrainian Forest Steppe were studied. Practical Value. The practical aspects of the using warm discharge water from energy facilities for the needs of the sturgeon aquaculture development at the current stage have been analyzed. The study results can be used for planning and adjusting technological schemes of intensive sturgeon aquaculture in the conditions of industrial-type farms. Keywords: sturgeon aquaculture, water temperature, hydrochemical parameters, warm water industrial fish farming, climate change.