Sodium Bicarbonate and Clove Oil as Potential Anesthetics for Nonsalmonid Fishes

Abstract
The use of chemical anesthetics, such as tricaine (MS-222), on fish that might subsequently be consumed by humans or animals is currently banned in Canada and restricted in the United States. Although “nonchemical” substitutes such as sodium bicarbonate or clove oil preparations have been used, appropriate concentrations have not yet been determined for nonsalmonid species native to North America. In this study, we found that solutions of 2.66 g sodium bicarbonate/L or 60 mg clove oil/L were optimal as anesthetics for use on walleyes Stizostedion vitreum at 10°C. At these concentrations, complete immobilization required 7.0 ± 0.5 (SE) and 4.3 ± 0.4 min, respectively, and recovery occurred in 4.9 ± 0.5 and 10.9 ± 1.2 min, respectively, for sodium bicarbonate and clove oil. These concentrations were also found to be suitable for use on smallmouth bass Micropterus dolomieu, northern pike Esox lucius, and lake sturgeon Acipenser fulvescens. Clove oil is recommended over sodium bicarbonate for surgical procedures; however, recovery took substantially longer when time under clove oil anesthesia exceeded 5 min.