Pink salmon, Oncorhynchus gorbuscha, eggs were collected from early-run and late-run spawners at Auke Creek, Alaska, and reared separately in a hatchery in deep-gravel incubators. Both groups of fry were marked the day after emergence, then released, unfed, to complete downstream migration. Early hatchery fry migrated downstream about 35 days ahead of late hatchery fry and about 55 days ahead of fry naturally hatched in Auke Creek. Hatchery fry developed faster than wild fry because hatchery water was warmer than Auke Creek water during egg incubation. Early hatchery fry had an average ocean life of 515 days and a marine survival of 0.17%; late hatchery fry had an average ocean life of 513 days and a marine survival of 1.46%. Low water temperatures experienced by early fry when they entered the estuary probably slowed their growth and made them more vulnerable to predators.