Use of Hydrogen Peroxide during Incubation of Landlocked Fall Chinook Salmon Eggs in Vertical‐Flow Incubators

Abstract

Six different hydrogen peroxide treatment regimes were evaluated in a series of three trials with landlocked fall Chinook salmon Oncorhynchus tshawytscha eggs incubated in vertical‐flow incubators. Six daily 15‐min hydrogen peroxide treatment regimes (1,000 mg/L; 1,000 mg/L with a decrease to 500 mg/L during estimated blastopore formation; 2,000 mg/L; 2,000 mg/L with a decrease to 500 mg/L during estimated blastopore formation; 2,500 mg/L; and 2,500 mg/L with a decrease to 500 mg/L during estimated blastopore formation) were compared with daily 15‐min treatments of 1,667 mg/L of formalin. Mortality at egg eye‐up and fry hatch and from eye‐up to hatch was significantly greater in eggs receiving the 2,500‐mg/L hydrogen peroxide treatments throughout incubation and in those receiving 2,500 mg/L hydrogen peroxide with a decrease to 500 mg/L during blastopore formation than in either of the 1,000‐mg/L hydrogen peroxide treatment regimes or the formalin‐treated eggs in the first trial. No significant differences in mortality were observed among any of the treatments in the subsequent two trials with maximum hydrogen peroxide concentrations of 2,000 mg/L. Fungal infestations were observed primarily in the incubation trays treated at either of the 1,000‐mg/L hydrogen peroxide regimens, as well as in those trays whose treatment concentrations were dropped to 500 mg/L during blastopore formation. Infestations were not observed in any of the formalin‐treated trays. If minor fungal infestation is acceptable, then daily hydrogen peroxide treatments of 1,000 mg/L for 15 min would probably provide adequate fungal control compared with formalin usage.

External Egg Membrane Characteristics of Landlocked Fall Chinook Salmon Eyed Eggs Treated with Hydrogen Peroxide or Formalin

“…However, the concentration we used (700 mg/L) is greater than the 500 mg/L currently allowed by the U. S. Food and Drug Administration for use on salmonid eggs (Winton 2001). We chose to use 700 mg/L because concentrations of more than 500 mg/L are needed for adequate fungal control in landlocked fall Chinook salmon eggs (Barnes and Gaikowski 2004). Grierson and Neville (1981) reported externus thickness averaging 3 m in rainbow trout, whereas Groot and Alderdice (1985) reported the thickness of the externus of anadromous Chinook salmon eggs to be 0.29 m. Our study found the externus of landlocked Chinook salmon eggs averaged 0.69 m, about 2.4 times greater.…”

Reduced Formalin and Hydrogen Peroxide Treatments during Walleye Egg Incubation

“…Fungal development in treated incubation jars was not detected until day 11 of incubation during any year. The lack of fungal growth, particularly in the 200-mg hydrogen peroxide/L jars, is somewhat surprising given the fungal infestations on walleye eggs treated with 500 mg hydrogen peroxide/L as reported by Gaikowski et al (2003) and the fungal growth reported on salmonid eggs receiving hydrogen peroxide concentrations of 500 mg/L or greater (Waterstrat and Marking 1995;Barnes et al 1998;Arndt et al 2001;Barnes and Gaikowski 2004).…”

Landlocked Fall Chinook Salmon Egg Survival during Jar and Tray Incubation at a Production Hatchery

“…However, a disadvantage of tray incubation is the need to use chemicals to control fungal growth. Hydrogen peroxide and formalin are both approved in the United States for fungal control on salmonid eggs [17], but formalin is more effective at fungal control and less toxic to developing landlocked fall Chinook salmon eggs [13]. However, formalin has been identified a suspected human carcinogen [6], and has defined exposure limits for hatchery personnel [7].…”

“…Well water (11°C; 360 mg/L total hardness as CaCO 3 ; 210 mg/L alkalinity as CaCO 3 ; 390 mg/L dissolved solids; 7.6 pH) supplied both incubator types. Flows were set at 12 L/min, which was the minimum required for slight rolling of the eggs in the jars, and are the same flows typically used during landlocked fall Chinook salmon egg incubation in trays [5,13]. Eggs were inventoried by water displacement [1] prior to placement into the incubation units.…”