Benzocaine and eugenol as anaesthetics for pompano juvenile Trachinotus marginatus

The aim of this experiment was to evaluate the efficacy of benzocaine and eugenol as anesthetics for Trachinotus marginatus juveniles. Five concentrations of benzocaine (25, 50, 75, 100, and 150ppm) and eugenol (25, 37.5, 50, 62.5, and 75ppm) were tested. The trials were conducted in glass aquariums filled with 30l seawater (salinity 30‰ and temperature 19°C). The fish (51.4±13.5g) were individually exposed to different concentrations of each anesthetic (n=5 for each concentration). They were measured and weighed under anesthesia, and then returned to another aquarium without anesthetic for recovery. The results were evaluated using Analyses of Variance (One-Way - ANOVA) followed by the test of Duncan (95% confidence level) when necessary. Anesthesia time varied from approximately 11min (25ppm) to 2min (150ppm) for benzocaine, and from 10min (25ppm) to 2min (75ppm) for eugenol. Recovery time ranged from 3min (25ppm) to 14min (150ppm) for benzocaine and from 2min (25ppm) to 8min (75ppm) for eugenol. Benzocaine and eugenol, both at 50ppm, induce quick anesthesia and recovery (3mim for anesthesia and 5mim for recovery) for juvenile Trachinotus marginatus, and therefore are considered efficient anesthetics for this species. However, it is important to emphasize that the cost of benzocaine is 1/3 lower than eugenol to anesthetize juvenile pompano.

anesthesia; handling; marine fish culture; Trachinotus marginatus