An evaluation of sedatives for use in transport of native fishes

Authors: Laura Tennant, David L. Ward

Year: 2014 (xlvi)

Abstract

Sedated ornamental fish are commonly transported with minimal water in plastic bags filled with oxygen, but these same methods are rarely used for transportation of threatened or endangered fishes for conservation purposes. We evaluated the effectiveness of three common sedatives for use in holding native fish when minimal water weight is desirable, such as for transportation. Juvenile (70-90 mm) bonytail, Gila elegans, were subjected to three sedatives, AQUACALM (metomidate hydrochloride), TRICAINE-S (tricaine methanesulfonate or MS-222), and AQUI-SÂ® 20E (eugenol). Fish were exposed to 0.0, 2.5, 3.0, 3.5, and 4.0 mg/L of AQUACALMâ„¢; 0.0, 55.0, 60.0, 65.0, and 70.0 mg/L of TRICAINE-S; and 0.0, 1.0, 2.0, and 3.0 mg/L of AQUI-S 20E. Fish were placed in plastic bags (8“x20”) filled with 1L of water and oxygen, at both low (n=5) and high densities (n=20). For each dose and density, we conducted three replicates, at 4-hour intervals until a 12-hour time period was reached. Of the three sedatives, AQUACALM was found to be highly variable in both induction and recovery times with high mortality rates. The optimum dose of TRICAINE-S for this application was 70.0 mg/L for both low and high densities of fish, although low mortality (5%) occurred in the high density treatment. AQUI-S 20E appears to be the best sedative we tested for holding small to large numbers of bonytail using these methods. A concentration of 1.0 mg/L exhibited good stress reducing capability, satisfactory induction and recovery times, and no mortalities at either low or high densities. Only one fish died in all of the control trails where no sedatives were used. This was unexpected and indicates holding fish using these methods without sedatives may be equally effective.

Resumen

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