398 American Fisheries Society 



go to another series of spawning areas. It is, I think, further 

 evident that netting fish from the rocky banks along the rapids 

 is well calculated to advantage the fisherman rather than the 

 fish, and to work serious havoc on certain waves of salmon 

 migration, for whether the fish go to a set of spawning 

 grounds connected with that bank only or are dispersed more 

 regularly over the different spawning grounds of the upper 

 river, the excessive catching will reduce to a minimum the 

 number of fish that escape, and may even be sufficient, by 

 virtue of the concerted fishing of a line of dip-netters along 

 this bank, to eliminate almost entirely the run that is passing 

 up at the time intensive fishing is practiced. 



In general it seems as if river fishing for commercial pur- 

 poses were inadvisable in Alaska streams. 



There is another physical factor which I am led to think 

 exerts a controlling influence in some cases, at least, on the 

 movements of the red salmon, and that is temperature. Of 

 this influence I have spoken more fully in another place. But 

 to avoid possible misunderstanding, a brief general statement 

 must be introduced here. At the start one should bear in 

 mind that the influence may be very real without being abso- 

 lute. In other words, it is only one of the factors which 

 determine activity and in a given case may be more or less 

 influential than another factor. Again it is contact with a 

 change in temperature rather than the absolute level of temper- 

 ature which ordinarily at least affects the red salmon. There 

 are two crucial points or types of choice in the fresh-water 

 career of the red salmon. First, when such a salmon, moving 

 upstream, reaches a place where two streams join, it must take 

 one or the other path — and, as already stated, its path is fixed 

 and invariable; it always selects one and not the other. Sec- 

 ond, when the red salmon, having attained the lake in which 

 it is to spawn, comes to choose a spawning ground, it selects 

 one or more areas for that purpose. While the choice of the 

 salmon in this respect has not been so generally recorded. 



