83 



All three salmon species have been reduced to small 

 fractions of their former abundance. These populations are 

 so low that without protection under the Endangered Species 

 Act (including a recovery plan) they are likely to soon 

 disappear. 



WHY ARE SNAKE RIVER 

 SALMON LISTED AS 

 THREATENED AND 

 ENDANGERED WHILE 

 OTHER SALMON ARE NOT? 



Five species of Pacific salmon exist in North America: 

 sockeye, pink, chum, chinook, and coho. Biologists usually 

 use the names of the rivers in which the salmon are found 

 and the seasons when the adult salmon return to their 

 spawning grounds to further categorize these five species. 

 This results in hundreds of "stocks" or "runs" of the five 

 salmon species. For example, the chinook salmon stocks 

 include Sacramento River winter chinook salmon, Columbia 

 River summer chinook salmon, Klamath River spring 

 Chinook salmon. Snake River spring/summer chinook 

 salmon, and Snake River fall chinook salmon, to name but a 

 few. 



When reviewing the status of different stocks, the National 

 Marine Fisheries Service reviews biological information to 

 determine if a stock or group of stocks represent an 

 "Evolutionarily Significant Unit" of the species. The Snake 

 River sockeye salmon were found to be an evolutionarily 

 significant unit and thus are listed as an endangered species. 

 The Snake River sockeye salmon evolutionarily significant 

 unit is made up of both anadromous sockeye and the 

 residual (non-migratory) sockeye population now found 

 only in Redfish Lake, Idaho. (Anadromous fish are those 

 that are bom in freshwater, migrate to the sea, and return to 

 freshwater to spawn.) 



The Snake River spring/summer chinook salmon were also 

 determined to be an evolutionarily significant unit. The run 

 is made up of more than 30 subpopulations located in 12 

 major subbasins and Salmon River tributaries. The Snake 

 River fall chinook evolutionarily significant unit is made up 

 of a single population which spawns in the mainstem Snake 

 River and the lower reaches of major tributaries downstream 

 from Hells Canyon Dam; plus the Lyons Ferry Hatchery 

 population, which was derived from the natural stock. 



WHAT IS THE GENERAL 

 LIFE HISTORY OF THE 

 SNAKE RIVER SALMON? 



Ssilmon have fascinating and complex life histories. They 

 travel as much as 900 miles upriver and climb to elevations 

 of 6,500 feet to reach 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 juvenile salmon emerge from the redds, they use 

 the stream or lake they were bom in as nursery areas. 

 Sockeye and spring/summer chinook live in these nursery 

 areas for one to two years before migrating seaward, but fall 

 chinook live in their nursery area for only a few months. In 

 the spring, the sockeye and spring/suimner chinook smolts 

 leave their nursery areas and start migrating to the ocean. 

 Fall chinook salmon leave their nursery areas and start 

 migrating to the ocean early in the summer. 



The Snake River salmon range from California to Alaska 

 and venture into the high seas of the Pacific where they 



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Salmon hfe cycle (Corps of Engineers) 



