Reduced Formalin and Hydrogen Peroxide Treatments during Walleye Egg Incubation

Abstract

Formalin use was evaluated as part of an investigational new animal drug study to determine its effectiveness in controlling fungus (water molds: Saprolegniaceae) on incubating eggs of the walleye Sander vitreus. Hydrogen peroxide was also evaluated as an egg treatment alternative to formalin. In total, three antifungal chemical treatment regimes (15 min daily) were evaluated during this study. Eggs were treated with 200 mg of hydrogen peroxide/L of water, 834 mg formalin/L, and the industry standard of 1,667 mg formalin/L. Untreated control eggs were severely infested with fungus and experienced survival to hatch that was significantly lower than that of the chemically treated eggs. Formalin and hydrogen peroxide treatments both controlled fungus and produced similar egg survival to initial hatch. However, walleye egg survival was significantly greater in jars treated with 1,667 mg formalin/L than in any other treatment. This study provided important new data on the use of chemical treatment concentrations lower than the standard of 1,667 mg formalin/L or 500 mg hydrogen peroxide/L to control fungus on incubating walleye eggs.