Physical Factors Influencing Survival to Emergence and Time of Emergence of Shoreslope-Spawned Kokanee Salmon in Flaming Gorge Reservoir, Utah-Wyoming

I used incubation baskets containing viable eggs and spawning substrate to estimate the survival to emergence and time of emergence of kokanee salmon Oncorhynchus nerka at depths to 20 m in Flaming Gorge Reservoir, Utah-Wyoming. Traps on the incubation baskets captured fry emerging from a known quantity of eggs. Water drawn into a syringe from an intragravel pipe buried near each incubation basket was used to determine intragravel dissolved oxygen concentrations throughout the intragravel period. Water from control baskets without eggs did not have significantly greater dissolved oxygen concentrations than adjacent water. A jar associated with each incubation basket collected sediment to determine absolute and organic sedimentation during the study. Temperatures at the substrate water interface were used to describe degree-days accumulated before emergence. Survival to emergence ranged from zero to 66% and was most significantly related to mean intragravel dissolved oxygen concentrations. Survival to emergence, mean intragravel dissolved oxygen concentrations , and organic sedimentation decreased with depth