422 American Fisheries Society 



ferent times and places have undergone striking changes, so 

 that it is impossible to predict their influence on the move- 

 ments of the fish. 



Still further complications are introduced if the new lake 

 covers up the original spawning grounds of the salmon. No 

 evidence has been adduced to show that the red salmon spawn 

 elsewhere than in shallow areas contiguous to the shores of 

 the lake. I have cited above some of the evidence to show 

 that the spawning grounds selected are not only shallow areas 

 of suitable material, but are also locations at which one finds 

 an influx of colder water, reducing the temperature at the 

 spawning period below that of adjacent waters. It is perhaps 

 unlikely that they can find new areas of precisely similar 

 character, and certainly the range of adaptability in the selec- 

 tion of a spawning ground, while unknown, is not likely to 

 be great. However, if the lake made by the dam has covered 

 up the area on which the fish were wont to spawn it is wise 

 to determine experimentally whether they can find another 

 equally fit place or be able to accommodate themselves at all 

 to the new conditions. Nevertheless, after all these possibili- 

 ties are taken into account, I fear that in some instances one 

 will still be compelled to face the unfortunate dilemma that 

 was suggested above: If the fish are to be preserved the pro- 

 ject for the utilization of the stream water must be abandoned, 

 or, if the stream is to be utilized according to the plans of the 

 engineers, the salmon run will be destroyed. 



There is, of course, the possibility that in some mechanical 

 fashion the fish could be diverted from the channel which had 

 been their natural route of migration for an unknown period 

 and thus led to ascend some other tributary which would carry 

 them up to a possible spawning ground, and that in the end 

 this new ground might prove suitable, or at least sufficiently 

 so to preserve in part the run of fish. Some experiments have 

 been interpreted as indicating that the red salmon could be 

 forced by circumstances to select new spawning grounds and 

 that these would prove to be adequate for the perpetuation of 



