The importance of the Salmon River as a 

 major contributor to runs of spring and 

 sunnmer chinook salmon in the Columbia 

 River is readily evident. On the average, 

 about 44 percent of the spring and summer 

 runs entered the Salmon River. The Willamette 

 River and the Columbia River network above 

 the mouth of the Snake River ranked second 

 and third in importance according to popula- 

 tion of chinook salmon. 



FALL-RUN CHINOOK SALMON 



Fall- run chinook salmon are distinguished 

 from the other runs by their period of migra- 

 tion; the fish enter the lower Columbia River 

 from late summer to late fall. Those spawning 

 in the tributaries of the lower Columbia River 

 enter from August through October; spawning 

 occurs shortly thereafter. The peak of fall 

 chinook salmon runs destined for the middle 

 reaches of the river arrives at Bonneville 

 Dam about the first of September; it is fol- 

 lowed by peaks at The Dalles and McNary 

 Dams 1 and 2 weeks later. 



Spawning Areas 



Fall-run chinook salmon in the Columbia 

 River drainage spawn principally in the lower 

 tributaries and in sections of the lower and 

 middle main stem (map 4). Spawning areas of 

 fall chinook salnnon in tributaries of the lower 

 Columbia River are presented in greater 

 detail in map 5. Table 5 gives the location 

 and extent of all known areas used by these 

 runs with brief descriptive notes . The number- 

 ing system was described previously for 

 spring- and summer-run chinook salmon. 



Logging by early white settlers was espe- 

 cially destructive to spawning areas for fall 

 chinook salmon in the lower Columbia Basin. 

 Stream beds were scoured by flushing logs 

 downstream to the mills. Logging wastes 

 were deposited in stream channels and often 

 formed logjams that became so large they 

 blocked access to the, stream. Removal of 

 cover from the watershed caused erosion, and 

 the resulting siltation choked the stream- 

 beds. 



Many watersheds now have a second growth 

 cover, and productive capacity of the streams 

 for rearing salmonids has improved accord- 

 ingly. Under the Columbia River Fishery 

 Development Program, conditions for spawn- 

 ing in tributaries of the lower Columbia have 

 been further improved by removal of obstruc- 

 tions in streams and construction of fish 

 ladders at natural falls and at dams. 



Construction of large river-run dams on 

 the main stem of the Columbia River has 

 unquestionably removed some of the nnost 

 valuable spawning grounds for fall- run chi- 

 nook salmon. Other dams, either under con- 

 struction or in the planning stage, will form 



reservoirs that will inundate nearly all of 

 the remaining spawning areas in the main 

 Columbia and Snake Rivers. Efforts are being 

 made to maintain these runs with artificial 

 spawning channels and hatcheries . Maintenance 

 of future runs in the rivers above Bonneville 

 Dam will hinge largely on the success of 

 these artificial means of production. 



The upper reaches of the main Columbia 

 River were used by fall chinook salmonbefore 

 the construction of Grand Coulee Dam started 

 in 1939. This run, however, had been reduced 

 considerably before the fish counts were 

 begun at Rock Island Dam in 1933. Fall-run 

 chinook salmon in this part of the Columbia 

 River used the main stream and lower portions 

 of the San Foil, Spokane, Fend Oreille, and 

 Kootenay Rivers. The upper limit of spawning 

 by fall chinook salmon in the Columbia River 

 has not been clearly defined because of the 

 difficulty in distinguishing between fall- and 

 summer-run chinook salmon on the spawning 

 grounds . 



Chapman (1943) described spawning of chi- 

 nook salmon in the main stem of the Columbia 

 River and estimated that in 1938, before the 

 blockage of salmon runs by Grand Coulee 

 Dam, 800 to 1,000 chinook salmon spawned in 

 a 3.Z-km. (2-mile) area below Kettle Falls. 

 Thus, between 15 and 20 percent of the total 

 run of 4,801 chinook salmon passing Rock 

 Island Dam in 1938 spawned in this area. 

 Other spawning areas reported by Chapman 

 were at Daisy and Rogers Bar- -about 32 and 

 64 km. below Kettle Falls. I believe that these 

 chinook salnnon spawners in this area of the 

 Columbia River were both summer- and fall- 

 run migrants. 



Additional spawning in the main stem was 

 reported by Fish and Hanavan (1948) during 

 aerial surveys of the Columbia River from 

 Grand Coulee Dam to the confluence with the 

 Snake River. Edson (1958a and 1958b) also 

 located main stem spawning areas during 

 preimpoundment studies at Priest Rapids, 

 Wanapum, and Rocky Reach Dams. Salmon 

 redds and spawning were observed on gravel 

 bars along the shore and at the mouths of 

 tributaries. 



The areas below the confluence of the Snake 

 River are more turbid, and it has been diffi- 

 cult to distinguish redds and spawning salmon 

 in this reach of the Columbia River. Evidence 

 indicates, however, that a large population of 

 fall chinook salmon spawns in the 160-knn. 

 stretch of river below McNary Dam. This area 

 will be inundated when John Day Dam is com- 

 pleted in 1968. 



Historically, chinook salmon (believed to 

 be fall-run fish) were reported by fishermen 

 to have ascended the Snake River to the foot of 

 Shoshone Falls, 976 km. above the mouth of 

 the Snake River, but probably most of the 

 run never reached this falls owing to diffi- 

 cult, turbulent rapids at Augur Falls, I6 km. 



16 



