For the first time, the possibility of using clove essential oil as an anesthetic for fish species in Ukraine, for which had not been previously used with this substance, was investigated. The optimal concentration of the anesthetic preparation was determined for working with six different fish species of various size and age groups under different temperature conditions. For the first time in Ukraine, a comparative assessment of three methods of preparing clove oil preparation for fish anesthesia - "cold," "hot," and "alcoholbased" - was conducted based on their anesthetic effect on fish. For the first time, the possibility of using clove oil to facilitate fish stunning (using African catfish as an example) in accordance with animal welfare legislation has been investigated. For the first time, an assessment of the economic efficiency of using clove oil for anesthesia of broodstock fish (using silver carp as an example) has been conducted. It has been established that clove oil has an anesthetic effect on sterlet within the concentration range of 0.05 to 0.15 ml/l. The optimal concentrations of the water emulsion prepared using the cold method for anesthetizing one to three-year-old sterlet are 0.05 and 0.07 ml/l, while for older fish, it is 0.1 ml/l. The clove oil preparation, in the form of a cold-prepared water emulsion, exhibits an anesthetic effect on African catfish within the concentration range of 0.05 to 0.15 ml/l within a water temperature range of 24-30° C. Optimal concentrations of the preparation for working with two-month-old juveniles of this fish are 0.05 ml/l, while for individuals aged six months and older, it is 0.1 ml/l. It has been determined that the degree of the anesthetic effect of clove oil on African catfish depends on the body mass of the fish. Larger fish take longer to enter a narcotic state compared to smaller individuals and recover to normal conditions more quickly. It has also been established that the temperature of the water emulsion of the preparation influences its anesthetic action on fish: entry into and recovery from the narcotic state is accelerated with increasing temperature. The effective concentration of the anesthetic in the form of a water emulsion prepared using the cold method is the same for two-year-old common carp and two-month-old Nile tilapia is 0.1 ml/l. The recommended concentration of the water emulsion prepared using the cold method for three-year-old and older grass carp is 0.03-0.04 ml/l, while for broodstock silver carp aged 6 years and older, it is 0.05-0.07 ml/l. It has been proven that all three known methods of preparing clove oil for fish anesthesia (hot, cold and alcoholic) provide a degree of anesthetic effect on African catfish, carp and Nile tilapia. At the same time, the drug from the hot method of preparing an aqueous emulsion turned out to be comparatively better for clary catfish, and for carp and tilapia - the drug from the alcoholic method of preparing a solution of clove oil. It has been established that the use of clove oil for deep anesthesia of marketsized African catfish during the process of preparing fish for forced slaughter relieves the fish of suffering and facilitates the working conditions of the staff. The recommended concentration of clove oil in a water emulsion prepared using the cold method of preparation is 0.1 ml/l, which ensures that the fish reach a deep anesthesia stage for approximately 5 minutes. The use of clove oil as a natural anesthetic for broodstock of silver carp is economically advantageous. Thanks to the extension of the reproductive use of these fish by more than 2 times, the costs for replenishing the fish population (at 2022-2023 prices) decrease by 32,924 UAH per 100 broodstock.
