Efficacy of Hydrogen Peroxide in Controlling Mortality Associated with Saprolegniasis on Walleye, White Sucker, and Paddlefish Eggs
M.P. Gaikowski, J.J. Rach, M. Drobish, J. Hamilton,
T. Harder, L.A. Lee, C. Moen, A. Moore-2003
North American Journal of Aquaculture, 65(4):
349–355
Abstract:
The efficacy of hydrogen peroxide in controlling
saprolegniasis on eggs of walleye Stizostedion
vitreum, white sucker Catostomus
commersoni, and paddlefish Polyodon
spathula was evaluated at four private, state, and federal
production hatcheries participating in an Investigational New Animal Drug
efficacy study (experiment 1; walleyes) and in a laboratory-based miniature
egg jar incubation system (experiment 2; walleyes, white suckers, and
paddlefish). Naturally occurring fungal infestations (saprolegniasis) were
observed on eggs in both experiments. Confirmatory diagnosis of infested
eggs from one hatchery in experiment 1 identified the pathogen as Saprolegnia
parasitica. During experiment 1, eggs were treated daily for 15 min
with either 0, 500, or 750 mg/L of hydrogen peroxide, and one trial compared
a 500-mg/L hydrogen peroxide treatment with a formalin treatment at 1,667
mg/L. Saprolegniasis infestation was observed in control egg jars, whereas
treatment with either formalin or hydrogen peroxide virtually eliminated the
infestation. Hydrogen peroxide treatments of 500 mg/L either increased egg
hatch or were as effective as physical removal of infested eggs in
controlling mortality. Although treatment with formalin at 1,667 mg/L
significantly increased the percent eye-up of walleye eggs compared with
that of those treated with hydrogen peroxide at 500 mg/L, the difference was
only 1.9–2.6%. In experiment 2, noneyed eggs were treated for 15 min every
other day with 0, 283, 565, or 1,130 mg/L of hydrogen peroxide until the
viable eggs hatched. Saprolegniasis infestation engulfed most control eggs,
whereas infestation of treated eggs was either reduced or not visible.
Hydrogen peroxide significantly increased egg hatch for all three species
tested in experiment 2. Although hydrogen peroxide treatments as low as 283
mg/L significantly increased walleye and white sucker hatch, treatments
between 500 and 1,000 mg/L are more likely to be effective in production egg
incubation systems.
(U.S. Geological Survey, Upper Midwest Environmental Sciences Center,
2630 Fanta Reed Road, La Crosse, Wisconsin 54603, USA)