Survival through Hatching of Eggs from Silver Salmon (Oncorhynchus Kisutch)

During the 1953–54 migration season 63 female silver salmon (Oncorhynchus kisutch) of the 1950 brood year were recovered in the traps at the University of Washington. Eggs from each female were fertilized by one male only and the eggs maintained as separate lots through hatching. Hatching was completed in most lots from 40 to 43 days after fertilization in water of about 52.5°F. The mortality of eggs was studied during three stages of development. Mortality appeared to be related more to the female than the male parent. Females arriving during the first portion of the run produced eggs that had higher survival than females arriving during the last portion of the run. Survival through hatching was 48 percent for about 198,000 eggs produced by the 63 females. This survival was considerably less than survival rates reported in the literature. A delayed entry into the ponds was associated with increased water temperature. Over-retention of the eggs may have caused the below-normal survival.