Rach, J.J., M.P. Gaikowski, T.M. Schreier, C.A. Perkins and S.M. Schleis. 2001. Safety 
of hydrogen peroxide to non-eyed and eyed rainbow trout (Oncorhynchus mykiss) eggs. 
Submitted to the U.S. Food and Drug Administration, Center for Veterinary Medicine, 
September 26. 202 pp.

      Non-eyed rainbow trout (Oncorhynchus mykiss) eggs were obtained from Trout Lodge 
(Sumner, WA) and shipped to the Upper Midwestern Environmental Sciences Center (UMESC), 
La Crosse, WI.  The efficacy of hydrogen peroxide to control egg mortality of rainbow trout was 
evaluated in a miniature egg jar incubation system.  Non-eyed eggs of rainbow trout were 
cultured at 12 and 15? C in egg jars and treated for 15 or 45 minutes every other day with 0, 
(untreated control), 1,000, 3,000, 5,000, or 10,000 mg/L of hydrogen peroxide until the eggs 
became eyed (non-eyed egg treatments).  Eyed eggs of rainbow trout were cultured at 12 and 15? 
C in egg jars and treated for 15 or 45 minutes every other day with 0, (untreated control)  1,000, 
3,000, 5,000, or 10,000 mg/L of hydrogen peroxide until the viable eggs hatched (eyed egg 
treatments).  The total number of eggs or fry in each egg jar at the termination of a trial was 
enumerated by direct counts. Concentrations of hydrogen peroxide were verified analytically for 
each treatment by a titrimetric method. 
       In all the rainbow trout non-eyed egg toxicity tests (12 and 15? C), hydrogen peroxide 
treatments reduced the probability of hatch in a dose-dependent manner.  The treatment groups 
had significantly lower percent egg hatches than the control group.  The 15 min. treatments were 
significantly less toxic than 45 min. treatments.
      In the rainbow trout eyed egg toxicity tests (12 and 15? C), all treatment groups had 
similar mean percent egg hatches as the control group.  There were no significant differences in 
percent mean egg hatch between the 15 or 45 min. treatments at any of the treatment 
concentrations.  
      Results from this study indicated that rainbow trout eggs may have a sensitive period in 
their development where the eggs are sensitive to 1,000 mg/L or greater treatments.  However, 
after the sensitive developmental period had passed, the eyed eggs became very resistant to 
hydrogen exposure and had a 5X safety factor for the recommended treatment concentration of 
1,000 mg/L at a 3X exposure time of 45 min.