First Use of Benzocaine as an Anesthetic in Black Sea Salmon (Salmo labrax) Fry

This study aims to find effective concentration and lethal dose of benzocaine in Black sea salmon and determine effect of exposure time to air on survival rate of fish. In the study total 600 fish used with 3.02 ±0.14 cm and 0.29 ± 0.03 grams. Fresh water for trout rearing used and water temperature was 11.4±0.66°C during experiment. In order to determine the effective anesthetic dose of benzocaine in Black Sea salmon 20 fry were treated with benzocaine solutions of 20, 25, 30, 35, and 40 mg/l. To determination of lethal concentration five benzocaine concentration tested as 60, 70, 75, 80, and 85 mg/l. fry were simultaneously released into 28 mg /l consecration benzocaine solution to determine effect of exposing fish to air. After being kept in an anesthetic substance for 3 minutes, all fish were taken on fish net at the same time and the fish were exposed to air for 5, 10, 15, 20 minutes respectively, and they were taken to separate tanks according to their exposure time to the air and observed for 24 hours, mortality were noted. Effective concentration and lethal dose were determined by Probit analysis. As a result, this study showed that 25-26 mg/l benzocaine is sufficient to anesthesia Black sea salmon and approximately 3 times of this dose is lethal for these fish. Also, it showed that air exposure after anesthetic use is very critical in salmon fish fry. After from 10 minutes 15 to 20 minutes of air exposure considerable fatalities occurred. Survival rates were 80 to 90 % between 5 and 10 minutes of air exposure however, when fish leave in air for 15 minutes and 20 minutes this rate fall drastically to below 20 % survival rate within first 24 hours.