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USGS · 70006860

Benzocaine as a fish anesthetic: efficacy and safety for spawning-phase salmon

P.A. Gilderhus
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Abstract

The anesthetic benzocaine was tested for efficacy and safety for spawning-phase chinook salmon (Oncorhynchus tshawytscha) and Atlantic salmon (Salmo salar) at federal fish hatcheries. Tests were conducted in the existing hatchery water supplies (soft water; temperatures, 10–13 °C. Crystalline benzocaine was dissolved in ethanol (1 g/30 mL), and aliquots of that stock solution were added to the water in test tanks. Benzocaine concentrations of 25–30 mg/L anesthetized most fish in less than 3.5 min, and most fish recovered in less than 10 min after 15 min of exposure. Safety margins were narrow; both species tolerated 30 mg/L for about 20 min, but 25 min of exposure caused deaths. For 15 min exposures, concentrations of 35 mg/L for chinook salmon and 40 mg/L for Atlantic salmon were lethal.

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BibTeXRIS

P.A. Gilderhus. 1990. Benzocaine as a fish anesthetic: efficacy and safety for spawning-phase salmon. https://doi.org/10.1577/1548-8640(1990)052%3C0189%3Abaafae%3E2.3.co%3B2

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