Efficacy and physiological responses of rock bream, Oplegnathus fasciatus to anesthetization with clove oil

We tested the efficacy (e.g., induction time, recovery time) of clove oil as an anesthetic for rock bream Oplegnathus fasciatus. In addition, we also evaluated the physiological response of fish to the anesthetic by measuring plasma cortisol and glucose. In general, fish exposed to higher anesthetic doses were rapidly induced but took longer to recover, while lower water temperatures resulted in longer induction and recovery times. Optimal anesthetic dose and water temperature were estimated to be 150 mgL− 1 at 20 °C, 100 mgL− 1 to 125 mgL− 1 at 24 °C, and 50 mgL− 1 to 75 mgL− 1 at 28 °C. Following the administration of 100 mgL− 1 of clove oil at 24 °C, the plasma cortisol level was highest (1.70 ± 0.148 μg/dL) after 1 h while the plasma glucose level was highest (80.0 ± 1.41 mg/dL) after 2 h. It took 2 days for the plasma cortisol and plasma glucose concentrations to return to pre-exposure levels.