SNAKE RIVER SALMON LIFE HISTORY Salmon have fascinating and complex life histories. They travel as much as 900 miles upriver and climb to elevations of 6,500 feet to reach natal spawning grounds. Snake River chinook and sockeye salmon share the same general life cycle. Eggs are deposited and fertilized by spawning adults in gravel "nests" (called redds) in the summer and fall. After the eggs hatch in the redds, the juvenile salmon use the stream or lake they were born in as a nursery area. Sockeye salmon live in nursery areas in Redfish Lake in Idaho for one to three years before migrating seaward. Spring/summer chinook live in nursery areas in small streams for one year but fall chinook live in nursery areas in larger streams for only a few months. Sockeye and spring/summer chinook smolts leave their nursery areas and start migrating to the ocean in the spring. Fall chinook salmon leave their nursery areas and start migrating to the ocean early in the summer. In the Pacific Ocean, Snake River salmon range from northern California to the Gulf of Alaska where they grow to maturity. Snake River salmon usually spend two to four years in the ocean before they return to freshwater. Snake River sockeye salmon enter the Columbia River in June and July and return to Idaho's Redfish Lake to spawn. Spring/summer chinook salmon enter the Columbia River from March through July and return to their natal streams to spawn. The spring/summer chinook that migrate early in the year tend to spawn in the upstream reaches of the Snake River's tributary streams, while those arriving later spawn in the river's lower reaches. Fall chinook salmon enter the Columbia River from August through October and return to the mainstem Snake River and lower reaches of major tributary streams to spawn.

The International Year of the Ocean Home Page is a publication of the NOAA Home Page Design and Construction Company