An evaluation of Supaverm® as a catfish specific piscicide

Authors: Ward, David L.*1, Morton-Starner, Rylan1, Vaage, Ben1

Year: 2015 (xlvii)

Abstract

The decline of native fishes in the southwestern United States is largely attributed to interactions with introduced fish. Attempts to remove nonnative fish from areas with native fish are common, but success is limited because very few tools are available for managing invasive fishes. We evaluated the chemical Supaverm® for potential use as a selective piscicide to remove catfish by testing its toxicity to three species of catfish and five species of native fish commonly found in Arizona. Channel catfish Ictalurus punctatus, black bulhead Ameiurus melas, flathead catfish Pylodictis olivaris, bonytail Gila elegans, humpback chub Gila cypha, roundtail chub Gila robusta, Sonora sucker Catostomus insignis and speckled dace Rhinichthys osculus, were exposed to Supaverm® for 72 hours at two doses (0.69 microliters/liter and 1.39 microliters/liter) in replicated laboratory treatments. Both doses of Supaverm® were successful at eradicating catfish without harming bonytail, humpback chub, roundtail chub, or speckled dace, but Sonora suckers were also killed by the treatment. The apparent selectivity of this chemical makes it a good candidate for further evaluation as a catfish specific toxin.