Within the tested range of 1000 - 7000 eyed eggs/ft² gravel substrate (1.08 - 7.53 eggs/cm²), the optimum stocking density for chum salmon (Oncorhynchus keta) eggs in shallow matrix substrate incubators occurred at 3000 - 4000 eggs/ft². Premature fry, which predominated early emergence, showed greater variability in lipid content than fry at peak emergence. Cumulative premature fry emergence was lowest at 3000 - 4000 eggs/ft² and highest at 5000 - 7000 eggs/ft². Early emerging fry are considered to be of lesser quality than peak emerging fry because the observed increase in variation in lipid content (i.e. primary energy reserve) may lead to increased variation in survival during seaward migration. Neither survival (from egg stocking to emergence) nor the gross body composition (determined by proximate analysis) of emerging fry were affected by egg stocking density. Development indices decreased in a linear fashion throughout emergence but the slope and intercept of the line did not differ among egg stocking densities. The frequency of yolk sac abnormalities was negligible in all treatments. The water content of fry increased from early to late emergence while dry weights remained relatively constant. The implications of this observation are discussed
