390 American Fisheries Society 



detect and perhaps still more difficult to explain but whicfi 

 nevertheless justify the student in attempting to find an ex- 

 planation of their actions in the environmental factors and in 

 expecting confidently to secure a solution of the problem ulti- 

 mately along these lines. 



I shall not attempt to enter here into a discussion of the 

 parent stream theory so tenaciously held by fishermen and in 

 the past so vigorously combated by some most distinguished 

 ichthyologists. I do not desire to appear as an attorney for 

 either side in this discussion. It is my object to tell as clearly 

 as possible of certain facts which I have observed so repeatedly 

 that they seem to me to hold a significant relation to the move- 

 ments of the salmon, and to leave the decision to the judg- 

 ment of others, both here and elsewhere, who may now and 

 in the future test them as facts and in their relations to the 

 problems under discussion, with a view to determining their 

 correctness and the justification of the relations observed and 

 of the conclusions drawn from such relations. 



MIGRATION ROUTE OF RED SALMON 



The precise route followed by the migrating fish in any 

 given stream has been discussed by various students of the 

 subject. There is little doubt that in all classes under natural 

 conditions it is uniform and precise. Two somewhat different 

 phases present themselves. These are related to the character 

 of the stream, and may be designated as the route taken by 

 the salmon in streams having a single spawning ground only; 

 and, second, that followed by the salmon in streams which 

 carry fish going to several spawning grounds. In both cases 

 one is struck by the peculiarities of the situation and the diffi- 

 culty of finding any a priori explanation for the facts. In 

 most cases these facts are clear and their invariability is shown 

 by the consistent testimony of the native races which have 

 always depended, as most of them do, upon the salmon for 

 food, at least in those regions where the salmon migration as- 

 sumes considerable proportions. It is evident that the con- 



