Efficacy of hydrogen peroxide to reduce Gyrodactylus species infestation density on four fish species

Objective

The ability to effectively treat parasitic infestations of fish is of high importance for fish culture facilities. However, tools or approved therapies for treating infestations on fish are limited. This paper summarizes results from four separate clinical field studies that evaluated the efficacy of hydrogen peroxide (H₂O₂; 35% PEROX-AID) for reducing Gyrodactylus spp. infestation density.

Methods

Three species of Gyrodactylus were studied (G. salmonis, hosts: Brook Trout Salvelinus fontinalis and Lake Trout S. namaycush; G. freemani, host: Yellow Perch Perca flavescens; G. hoffmani, host: Fathead Minnow Pimephales promelas) before and after the application of immersion H₂O₂ therapy.

Result

Parasite density was significantly reduced for each parasite × host combination to which H₂O₂ therapy was applied. Two clinical field studies in salmonids were found to demonstrate substantial effectiveness that enabled 35% PEROX-AID approval.

Conclusion

Further assessments of Gyrodactylus spp. could expand the use of H₂O₂ for controlling these parasites in aquaculture. Specifically, H₂O₂ was effective at all levels tested (50 or 75 mg H₂O₂/L for 60 min for the Yellow Perch and Fathead Minnow clinical field studies; 100 or 150 mg H₂O₂/L for 30 min regardless of salt pre-treatment for the Brook Trout study; and 100 mg H₂O₂/L for 30 min or 50 mg H₂O₂/L for 60 min for the Lake Trout study).