The objective of the study was to evaluate the efficacy of 2-phenoxyethanol as an anesthetic in great sturgeon under two experiments . First, fish were exposed to 0.3, 0.5, 0.7 and 0.9 ml/L 2-phenoxyethanol and times to induction (deep anesthesia) and recovery from anesthesia were measured. 2-phenoxyethanol induced deep anesthesia at all concentrations tested. For assessing the impact of each aforementioned concentration on physiological responses of great sturgeon, hematological indices, plasma metabolites, electrolytes, enzymes and cortisol levels were measured. The use of 2-phenoxyethanol causes a significant increase in RBC values at 0.9 ml/L concentration and a parallel increase in hemoglobin and hematocrit values were observed at this concentration (P < 0.05). 2-phenoxyethanol anaesthesia had no effect on WBC, MCV, MCH and MCHC levels when compared to control group (P > 0.05). Serum glucose, cholesterol and cortisol levels were significantly high in 0.3 and 0.5 ml/L 2-phenoxyethanol. Moreover, AST levels were increased in fish exposed to the 0.3 ml/L 2-phenoxyethanol comparing with the control group (P < 0.05). There were no significant differences in serum levels of total protein, triglycerides, ALP, ALT, Cl-, Na+, K+, Ca2+, and Mg2+ (P > 0.05). In this study alteration in hematological and serum biochemical indices were dose and time dependent, respectively. The outcome of these experiments shows that 2-phenoxyethanol at a concentration of 0.7 ml/L is suitable anesthetic for great sturgeon because of its fast effect and quick recovery time. In addition, it appears that exposure to 2-phenoxyethanol with 0.7 ml/L for 171 s was associated with the lowest effects on the hematological and serum biochemical indices in great sturgeon and therefore would be recommended as an eligible dose for hematological studies in this species
