Evaluation of Two Formalin Concentrations During Yellow Perch Egg Incubation

Abstract

Daily 15-minute treatments of formalin at 1667 mg/L are typically used to prevent water mold infestations in coolwater fish eggs. This study evaluated the use of a reduced concentration of 834 mg/L during yellow perch Perca flavescens egg incubation until the eyed stage of egg development. No water mold was observed on the perch eggs using either formalin treatment regime. Median survival to the eyed stage of egg development was not significantly different between the treatments and approached 90%.  There was also no significant difference in egg survival to hatch. In addition, fry length at hatching, although relatively short overall, was not significantly different between the formalin treatment concentrations. The results of this study indicate that reducing daily 15-minute formalin concentration from 1667 to 834 mg/L during yellow perch egg incubation will not affect survival through hatch or larval length at hatching.