Our tests were conducted using one type of water and this study focused solely on the
culture of rainbow trout eggs in fresh water. Variability of water-quality factors, such as
total hardness, pH, and temperature, can increase or decrease the toxicity of some
chemicals (Piper et al., 1982 and Howe et al., 1994). Rach (personal communication,
1995) has reported that hydrogen peroxide treatments of 500 ~1 1-l were not toxic to
eggs of walleye, northern pike, white sucker, lake sturgeon, and channel catfish and fish
toxicity significantly increased with water temperature. If water quality factors differ
greatly from those used in our study, we suggest treating a subsample of eggs before
treating the entire lot to verify any changes in sensitivity.