Upper Midwest Environmental Sciences Center
Toxicity of hydrogen peroxide treatments to rainbow trout eggs
Gaikowski, M. P., Rach, J. J., Olson, J. J., and Ramsay, R. T., 1998, Toxicity of hydrogen peroxide treatments to rainbow trout eggs: Journal of Aquatic Animal Health, v. 10, no. 3, p. 241-251.
Hydrogen peroxide treatments of 0, 500, 1,000, and 3,000 mu L/L, concentrations that were multiples of the Low Regulatory Priority limit of 500 mu L/L,, were administered for 15 min every weekday (Monday-Friday) to eggs of rainbow trout Oncorhynchus mykiss and steelhead (anadromous rainbow trout) to determine the margin of safety existing for standard egg treatments. All untreated and treated eggs remained free of fungal infection throughout incubation. Hydrogen peroxide treatment reduced the mean percent hatch of rainbow trout eggs by 1.4-5.9% among those treated at 500 mu L/L, 6.8-15.4% among those treated at 1,000 mu L/L, and 13.2-25.3% among those treated at 3,000 mu L/L, Mean percent hatch of rainbow trout eggs treated at 1,000 mu L H2O2/L was 7% lower than that for eggs treated at 500 mu L H2O2/L. Mean percent hatch of Skamania strain steelhead was significantly reduced by hydrogen peroxide treatment, whereas the mean percent hatch of Ganaraska strain steelhead was similar to the mean percent hatch of rainbow trout eggs. Daily percent mortality of rainbow trout eggs increased significantly from day 6 to day 10 (78-135 daily temperature units, DTUs degrees C) of incubation. Discontinuing hydrogen peroxide treatments to Skamania strain steelhead eggs from day 7 to day 11 (78-105 DTUs degrees C) of incubation significantly increased the probability of eggs reaching the eyed egg stage. The mean percent hatch of rainbow trout eggs treated with hydrogen peroxide at concentrations up to 1,000 mu L/L may be increased if no treatments are administered between 70 and 10 DTUs degrees C. Mortality of sac fry was not observed at hydrogen peroxide concentrations of 1,000 mu L/L or lower. Fish culturists should be aware that other species or strains may be more sensitive than rainbow trout. Other species and strains should be initially treated with hydrogen peroxide at 500 mu L/L until monitoring of egg mortality identifies the presence or absence of a sensitive period.
Keywords: Chemical treatments