Use of hydrogen peroxide and formalin treatments during incubation of landlocked fall chinook salmon eyed eggs

The effects of daily hydrogen peroxide treatments (700 mg/L for 15 min) from the eyed stage of egg development to fry hatch were compared with those of formalin treatments (1,667 mg/L for 15 min) and the physical removal of dead eggs from vertical flow incubator trays containing eyed eggs of landlocked fall chinook salmon Oncorhynchus tshawytscha. Both the hydrogen peroxide and formalin treatments significantly (P < 0.05) increased embryo survival to hatch relative to that resulting from the removal of dead eggs alone. No fungal or bacterial growth was observed in any of the incubator trays throughout the experiment. Although formalin is currently the only approved fish egg fungicide in the USA, hydrogen peroxide treatments of 700 mg/L for 15 min from egg eye-up through fry hatch would also maximize the survival of landlocked fall chinook salmon embryos and decrease hatchery labor requirements.