COMMUNICATIONS Effect of Iodophor Concentration and Duration of Exposure during Water Hardening on Survival of Atlantic Salmon Eggs

Abstract.—Because of disease transmission concerns, field studies to evaluate the impact of water-hardening eggs at different concentrations of polyvinylpyrrolidone iodine (iodophor) for various times of exposure have rarely used untreated controls. Additionally, U.S. Fish and Wildlife Service protocol requires a subsequent post–water-hardening surface disinfection for salmonid eggs transferred between stations. The cumulative im-pact of this second disinfection on survival has not been fully investigated for Atlantic salmon Salmo salar. This study compared the percent of eye-up Atlantic salmon eggs that had been water-hardened with iodophor treat-ments at 50, 100, and 150 mg active ingredient/L for 30, 60, and 90 min with that of untreated controls and also examined the impact on egg survival of a secon