The effectiveness of tricaine, quinaldine sulfate and metomidate as anesthetics for larval fish

Abstract

Tricaine, quinaldine sulfate, and metomidate were compared as anesthetics for larvae of two species of fish, red drum ( Sciaenops ocellatus) and goldfish ( Carassius auratus). Larvae were exposed to various concentrations of each anesthetic and the percentages of fish reaching stage 4 of anesthesia, post-exposure recovery, and survival were recorded. Effective concentrations were defined as those which induced stage 4 of anesthesia within 3 min after exposure with a recovery time of 10 min or less. Post-exposure survival of 100% was an additional criteria used to define effective anesthetic concentrations. The lowest effective concentration of tricaine for red drum was 55 mg/l (26 °C), while 50 mg/l (24 °C) was the lowest effective concentration for goldfish. The lowest effective concentration of quinaldine sulfate for red drum was 35 mg/l (26 °C), while 60 mg/l (24 °C) was the lowest effective concentration for goldfish. Metomidate was found to be an ineffective anesthetic for both red drum and goldfish larvae based upon survival and recovery times. Mortality occurred in red drum larvae at all tested concentrations of metomidate. Larvae of both species that survived anesthesia with metomidate had longer induction and recovery times compared to larvae exposed to tricaine and quinaldine sulfate.