other areas to start new runs. The possibility 

 of expanding spawning runs to middle Colum- 

 bia tributaries also appears good in view of 

 the success at Icicle Creek. The prospects are 

 good for an increase in size of the run to an 

 average of about 5 million fish, providing water 

 quality can be improved and that some unfa- 

 vorable factor does not occur. 



SOCKEYE SALMON 



Sockeye salmon are fail spawners. The 

 principal upstream migration starts in May 

 and continues through August. The migrants 

 reach their native lakes during July, August, 

 and September before moving onto spawning 

 grounds in streams or lake shoals. Runs of the 

 upper Salmon River into Redfish Lake and to 

 the Okanogan River start spawning in late 

 September and peak in mid-October. The 

 Wenatchee River fish spawn from early to late 

 September. 



Eggs hatch in the stream or lake gravel 

 from January to March and the fry do not 

 leave the gravel until most of the yolk is ab- 

 sorbed (March to May). The young fry swim 

 into their native lake and remain variable per- 

 iods of time. Most move out the next spring 

 but others remain a year or two longer before 

 migrating to the North Pacific Ocean. Most 

 in the Columbia River mature at age 4 but 

 many are 3 and 5 years old. 



While in the ocean, sockeye salmon are sky 

 blue above and silver below ; upon their ar- 

 rival at a lake system the upper portion fades 

 to a pinkish gray. Just before the fish move 

 onto the spawning ground, they turn crimson, 

 or brick red, and the heads become a bright 

 olive green. At spawning time, they are not 

 easily frightened and are easy prey. 



Sockeye salmon are highly regarded as 

 food; their flesh is deep red, firmer than that 

 of other salmon, and lends itself readily to 

 canning. The quality of flesh of Columbia 

 River sockeye salmon is outstanding — probably 

 because it has a longer spawning migration 

 than most stocks and has large reserves of fat. 

 The fish in the Columbia River, however, are 

 among the smallest of this species in the Pa- 

 cific northwest. The average 4-year-old sock- 

 eye salmon of the Columbia River is about 1.7 

 kg., whereas the average Canadian and Alaska 



specimens weigh about 3 kg. The 3-year-old 

 Columbia River sockeye salmon weighs about 

 1 kg.; the 5- or 6-year-old fish may weigh as 

 much as 5 kg. 



The sockeye salmon is the only one of the 

 five species of Pacific salmon in North America 

 that has successfully maintained itself wholly 

 in fresh water on a large scale without the aid 

 of artificial propagation. Kokanee, as the non- 

 anadromous variety is called, are in most lakes 

 where the anadromous form exists or existed.' 

 They also have been successfully introduced 

 into many cold-water lakes throughout the 

 United States; they spawn naturally when 

 suitable conditions are present, but in many 

 areas artificial propagation is necessary. 



Marking experiments in the Columbia and 

 Fraser River systems have proved that kokanee 

 sometimes migrate from their native lakes to 

 the ocean and return as mature sockeye salmon. 

 Kokanee from Lake Wenatchee were reared at 

 Leavenworth National Fish Hatchery and 

 marked by fin clipping. One group was re- 

 leased in Icicle Creek and the other in Lake 

 Wenatchee. Mature sockeye salmon bearing 

 these marks returned later to the lower Co- 

 lumbia River, where some were caught in the 

 fishery; others returned to the Wenatchee area 

 in numbers similar to those in other marking 

 experiments on regular sea-run stock.' Cultus 

 Lake, tributary of the Fraser River system in 

 British Columbia, was the scene of another 

 kokanee marking experiment (Foerster, 1947). 

 Releases from the outlet of Cultus Lake re- 

 turned as mature sockeye salmon of the same 

 average size as the usual sea-run stocks. (In 

 Wenatchee Lake kokanee produced mature 

 sockeye salmon 0.09 to 0.18 kg. smaller than 

 the normal sea-run variety.) 



° Steelhead trout frequently become resident rainbow 

 trout and also have the same ability to maintain them- 

 selves in fresh water. Clinton Stockley and Ken KroU 

 (biologists, Washington Department of Fisheries) re- 

 port that a small population of chinook salmon has 

 taken residency in Lake Cushman Reservoir (Wash- 

 ington State), spawning in an inlet stream, and feed- 

 ing in the reservoir to maturity. Also, the first 

 generation survival of coho and chinook salmon in 

 the Great Lakes (Michigan and Superior) will be 

 watched to see if these species can be permanently 

 established. 



* Manuscript by Mitchell G. Hanavan, Chief (re- 

 tired). Branch of Anadromous Fisheries, Bureau of 

 Commercial Fisheries, Washington, D.C., and Leonard 

 A. Fulton. 



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