28 FISHERY AND FUE INDUSTRIES OF ALASKA IN 1912. 



number and extent as yet to bring about such results. The natural 

 grounds remain in almost their original character and area, hence the 

 absence of care or forethought in respect to them. These matters 

 seldom receive attention until appreciable damage has been inflicted. 

 Furthermore, it is, perhaps, generally supposed that artificial hatch- 

 ing may prove an adequate substitute for any damage done the 

 natural beds when the time arrives to make provision. As pointed 

 out above, there are other considerations. In the case of the more 

 valuable salmon it seems that to get healthy spawn it is requisite 

 that the fish mature m fresh water, of appropriate temperature, 

 volume, and purity; without this a hatchery could not be operated. 



While no actual figures are available, there appears to be no reason 

 to doubt that crowding the spawning beds necessarily results in loss 

 of spawn. It follows then that an mcrease of suitable ground would 

 work to the advantage of the fishery. There are quite a number of 

 streams in Alaska in which faUs prevent the entrance of sabnon. 

 In some of these a fish way could be provided at comparatively small 

 expense that would admit spawnmg fish to considerable areas of 

 suitable beds. Along the same line, perhaps, assistance could be 

 rendered by facilitating the ascent of such falls as are now passable 

 only at certain stages of water. The actual value of such improve- 

 ments can be ascertained only by trial and observation. The con- 

 tinuance of the fishery m spite of the heavy drains made upon it goes 

 far to prove that the supply may be maintained by permitting a 

 fraction only of the adults to reach the beds. From this it may be 

 reasoned that the possible product is controlled by the area of suitable 

 spawning ground rather than by number of spawning fish, given, of 

 course, a sufficient number of spawners to seed the ground. If this 

 argument is valid, measures to extend and improve the groimds will 

 add proportionately to the output. 



Hatcheries, while now beyond question merely as to whether they 

 are effective in furtherance of the maintenance of the fishery, are not 

 always considered from their purely economic value. The real 

 question is not. Will hatcheries, given the parent fish, perpetuate 

 the supply? — for that is answered on the Sacramento Eiver — but, 

 Will they do it at least cost? As at present conducted, the whole 

 value of the hatcheries lies in the greater percentage of fry they 

 produce from a given number of eggs. This value can probably be 

 expanded to cover at least a portion of the life of the young after 

 hatchmg, or, to be more exact, after yolk absorption, for no hatchery 

 worthy of consideration now plants yolk fry. The real question 

 then is: Is the cost of operation of the hatchery exceeded by the 

 value of the fish saved to commercial consumption ? 



For example, assume in a given stream a run of 100,000 fish. 

 Assume, to maintain that run, 50,000,000 fry must reach the free- 



