The effect of moist air incubation conditions and temperature on chinook salmon egg survival
Fisheries Bioengineering Symposium: American Fisheries Society Symposium 10
Colt J;White RJ;
American Fisheries Society
Eggs of chinook salmon Oncorhynchus tshawytscha were incubated in water or in moist air for 6-, 12-, or 24-h intervals between 0.5 h of flooding with water at temperatures of 10.2-20.2 degree C. Egg mortality was very rapid at high temperatures. Total mortality occurred before hatching at temperatures greater than 17.2 degree C, regardless of whether eggs were incubated in water or moist air. Significant (P > 0.05) egg losses occurred at temperatures greater than 14 degree C. Hatching rates appeared to be affected primarily by temperature. However, the 12- and 24-h moist air treatments showed a slight delay in hatching compared with eggs incubated at similar temperatures in 6-h moist air treatments or in water. Alevin losses occurred at the higher temperatures but were not associated with exposure to moist air. Response surface analysis of mortality indicated that, below the lethal threshold of 14 degree C, incubation in moist air with 4-8% water exposure per day (about 6-10-h intervals between flooding) should produce greater egg survival than if eggs were incubated entirely in water.