where springs issue from the l)Ot- 

 tom, or in the gravel of the outlet 

 from the lake. Red salmon gen- 

 erally are 4 years of age at spawn- 

 ing; a few may be younger and 

 many may be 5 or more years old. 



The young red salmon, after 

 their emergence from the gravel, 

 descend to the lake and remain 

 there for a year or more before fol- 

 lowing the river to the ocean. As 

 red salmon feed upon plankton 

 (minute organisms in the water), 

 the length of residence in the lake 

 may be determined by the abund- 

 ance of plankton. Some of the 

 young fish may remain in the lake 

 throughout their lives, spaw^ning 

 and dying at 4 years of age like 

 their sea-grown brothers but usually 

 attaining only about one-half their 

 size. The progeny of these lake- 

 dwelling forms may descend to the 

 ocean and return as normal sea-run 

 specimens. 



The run of red salmon into the 

 rivers begins in June and continues 

 tiiroughout August. Spawning 

 may start as early as July in north - 

 erii streams and be concluded in 

 September, Jbut in the upper Colum- 

 bia spawning is complete early in 

 October. 



Oncorhynchiis hisiifch: Silver, 

 coho, silversides. 



Range : Sacramento River to Ber- 

 ing Strait, but most abundant in 

 Puget Sound and British Columbia 

 waters. Present in most streams of 

 the Pacific coast. 



Weight: In Alaskan waters the 

 species attains an average weight of 

 about 14 pounds, but in the streams 

 to the south the weight is consider- 



ably less. Maximum weight is 

 about 30 pounds. 



Most mature silver salmon enter 

 fresh water from late September to 

 early November, rJthough some may 

 appear earlier or much later. Of 

 the five species of salmon, the silver 

 is best adapted to diverse condi- 

 tions. It spawns in the very head- 

 waters of streams as well as very 

 close to salt water. The wide vari- 

 ations in time and place of spawn- 

 ing result in differences in time of 

 hatching and in development of the 

 fry and fingerlings. 



Silver eggs usually hatch during 

 the early spring, and a few of the 

 young fish migrate soon after to the 

 ocean. Most of the young fish re- 

 main in fresh water throughout the 

 summer and the following winter, 

 usually migrating to the ocean early 

 in their second year. Because of 

 this tendency to remain in fresh wa- 

 ter for a year or more, the silver, 

 like the red salmon young, must de- 

 l)end upon the food supply of a lim- 

 ited fresh-water area, and survival 

 probably is jeopardized during 

 years of heavy spawning and sub- 

 sequent overutilization of available 

 food. 



Investigations have indicated that 

 young silver salmon in the ocean 

 may remain relatively close to their 

 home stream, often remaining in 

 estuaries and inside passages while 

 making remarkable growth. The 

 majority return to their respective 

 streams to spawn during the fall of 

 their third year. 



The silver salmon is taken, along 

 with the Chinook, in the offshore 

 commercial troll fishery and is 



10 



