Gaikowski, M.P., J.J. Rach, A. Moore, J. Hamilton, D. Smith, and T. Harder.
2001d.  Efficacy of hydrogen peroxide to control mortality associated with 
saprolegniasis on eggs of channel catfish (Ictalurus punctatus), paddlefish 
(Polyodon spathula), smallmouth bass (Micropterus dolomieui), and walleye 
(Stizostedion vitreum).  Study report for supporting clinical field trials 
conducted under INAD 10-023.  Submitted to the U.S. Food and Drug Administration 
Center for Veterinary Medicine.  August 28, 2001.  23 pp.

Fish and fish eggs are commonly parasitized by numerous species of aquatic 
fungi belonging to the family Saprolegniaceae.  Saprolegnia parasitica and 
other fungal species have caused serious production losses to aquaculture.  
Clinical field trials were conducted to describe the efficacy of hydrogen 
peroxide treatments to control fungus on cool- and warmwater fish eggs.  
Trials were completed with eggs of walleye Stizostedion vitreum, paddlefish 
Polyodon spathula, smallmouth bass Micropterus dolomieui and channel 
catfish Ictalurus punctatus at six private, state, or federal production 
hatcheries and research facilities using production-type egg incubation systems.  
Treatments were initiated with non-eyed eggs and continued until all 
viable eggs had hatched.  Naturally occurring fungus infections were observed 
on eggs in all trials and the fungal pathogen Saprolegnia parasitica was 
positively identified from egg samples submitted by the Rathbun Research 
Facility, the Dundee State Fish Hatchery, and the Blind Pony State Fish Hatchery.  
The fungal pathogen S. ferax was also identified in the egg samples from 
the Blind Pony State Fish Hatchery.  Eggs were treated daily for 15 minutes 
at selected hydrogen peroxide concentrations between 250 and 1,000 mg/L.  
All trials included untreated controls.  In the walleye egg trial, hydrogen 
peroxide treatment of 500 mg/L was as effective as physical removal of fungused 
eggs to control mortality.  Fungus was observed in all control egg jars but 
was virtually eliminated from walleye and channel catfish eggs treated with 
hydrogen peroxide.  The percent hatch observed in untreated smallmouth bass 
control eggs was not significantly different from those eggs treated with 
hydrogen peroxide.  The number of fungused eggs removed daily from the egg jars, 
however, was significantly lower in those egg jars treated with hydrogen peroxide.  
From the limited paddlefish data collected, hydrogen peroxide treatment without 
continuous egg movement (rolling) from fertilization through hatch was not as 
effective as rolling alone to increase the probability of egg hatch.