Potential Indicators of Egg Viability in Landlocked Fall Chinook Salmon Spawn with or without the Presence of Overripe Eggs

Abstract

Abstract Selected reproductive characteristics obtained during the spawning of landlocked fall chinook salmon Oncorhynchus tshawytscha from Lake Oahe, South Dakota, were evaluated for their use as predictors of embryo survival to the eyed egg stage. Spawn was categorized according to the presence or absence of observable overripe eggs. No significant differences in female length, female weight, the number of eggs per female, egg size, the amount of ovarian fluid released during spawning, and ovarian fluid specific gravity, pH, and conductivity were observed between spawn containing overripe eggs and spawn without overripe eggs. Conductivity was significantly positively correlated to embryo survival only in spawn without overripe eggs, while the total number of eggs per female was only positively correlated to embryo survival in spawn with overripe eggs. Spawning female weight, the number of eggs per female, and egg size were significantly different in spawn containing overripe eggs where no embryo surviva...