Use of clove oil to anaesthetize larvae of Russian sturgeon (Acipenser gueldenstaedtii)

The efficacy of clove oil as an anaesthetic was evaluated in larvae of Russian sturgeon (Acipenser gueldenstaedtii) using four anaesthetic concentrations varying from 0.20 to 0.75 g L-1 Mean length, 13.7 +/- 0.70 mm, 44 larvae placed individually to the anaesthetic bath, and induction (I-1 and I-2) and recovery times (R-1 and R-2) recorded at 18.0 + 0.01 degrees C. Larvae failed to respond to external stimuli >= 3 min (3.19 min) and recovered in >= 5 min (5.10 min) at 0.20 g L-1 and at the other three doses larvae reached to syncopal stage in < 3 min and recovered from anaesthesia < 10 min. As expected, the higher dose of clove oil resulted in significantly shorter anaesthesia induction and longer recovery times. While correlation coefficients between induction time and dose determined as negative; r = 0.87 and a positive correlation r = 0.86 has been found between doses and recovery times (P < 0.01). The study demonstrated that clove oil can be used as an effective anaesthetic in larvae of Russian sturgeon and higher dose of clove oil prolonged the recovery time.