WHY THE SALMON HATCHERY? 



To maintain the resource, enough of the 

 mature salmon entering a river must spawn 

 successfully. Soil erosion and subsequent 

 silting of streams, domestic and industrial 

 pollution, small irrigation dams, and major 

 multiple-purpose dams have in varying de- 

 grees limited spawning and destroyed young 

 salmon. To counteract the effects of these, 

 salmon hatcheries are necessary. 



Hatchery salmon released into streams aug- 

 ment the natural runs of adults returning to 

 spawn. Often when ancestral spawning areas 

 have been blocked, hatcheries have been able 

 to start runs in other streams by planting 

 fish in them. These fish, after their interlude 

 in the ocean, return to the area of their plant- 

 ing, and new runs are established. 



Although natural reproduction is desirable 

 because of its economy, the hatchery is be- 

 coming increasingly necessary to maintain 

 the resource where natural reproduction has 

 become wholly or partly impossible. 



