Safety and efficacy of Virkon® aquatic as a control tool for invasive Molluscs in aquaculture

Virkon® Aquatic is a broad-spectrum disinfectant used in aquaculture as a disinfectant for footwear, nets, and equipment for protection from bacteria, viruses and one fungus. Recent studies provided data to support Virkon® Aquatic as a tool to kill invasive molluscs and other organisms in aquaculture and field settings. This study reports the efficacy of Virkon® Aquatic to kill New Zealand mudsnails Potamopyrgus antipodarum and quagga mussels Dreissena rostriformis bugensis from aquaculture facilities. To address the safety of Virkon® Aquatic used in aquaculture and field settings, the safety limits of Virkon® Aquatic to Steelhead trout Oncorhynchus mykiss were tested. Short-term emersion of fingerlings for up to 3.5 h in diluted concentrations of 30 mg/L showed no observable toxic effects. Smaller fry were somewhat less tolerant but survived exposures for up to 5 h in 10 mg/L. We conclude that the risks to fish are low if residues of the chemical remained on equipment, or if containers with disinfecting concentrations of 20 g/L were spilled into raceways or around fish holding systems. We suggest that this and additional studies may be helpful to support a label claim of this disinfectant for targeted invasive invertebrate species.