38 IffiNDALL: NEW ENGLAND SALMONS. 



the upper limits of streams, may take place, and he classifies as anadromous migrations 

 those movements from oceanic to continental waters, whether demersal or pelagic, 

 from deep to shallow water, from offshore to inshore, and estuaries, from river to the 

 stream, etc. 



This classification is a logical one, for the movements all lead up to the same end and 

 are in obedience to the same demands of 'the laws of nature.' But to state that the 'laws 

 of nature' are responsible for the movements merely restates the question of why the 

 fish are migratory or anadromous. The question is, what are these 'laws of nature' 

 which impel the king salmon, for instance, to cease to feed and to ascend Pacific coast 

 streams a thousand miles or more, reproduce its kind once only in its lifetime, then 

 perish? Or, what are the laws which impel the sockeye salmon to ascend certain streams 

 only which have lakes at their head fed by waters from melting snows, there, like the 

 king salmon to reproduce but once in its life and die? To state that the impulse is 

 'instinct' without defining the term, also simply restates the question. 



'Instinct,' Jordan (1905a, p. 154) says, 'is automatic obedience to the demands of 

 conditions external to the nervous system.' He again says: 'The greater the stress of 

 environment, the more perfect the automatism, for impulses to safe action are neces- 

 sarily adequate to the duty they have to perform. If the instinct were inadequate, the 

 species would have become extinct. The fact that its individuals persist shows that they 

 are provided with the instincts necessary to that end. Instinct differs from other alHed 

 forms of response to external conditions in being hereditary, continuous from generation 

 to generation.' 



Referring to the view of various investigators, Jordan mentions that some regard 

 instinct as the natural survival of automatic responses which were most useful to the 

 life of the animal, the individual having less effective methods of reflex action perishing, 

 leaving no posterity. 



Anadromy, then, is one 'adequate' means to an end, that of reproduction, which 

 occurs periodically; or in the words of Gurley (1902, p. 409) '. . . cyclical recurrence of 

 instinct is the outcome of cyclical recurrence of environmental stimuh.' In a considera- 

 tion of movements attributed to the 'constitution of the nervous system,' Gurley in- 

 dicates (p. 408) that the real question is: 'How did the nervous system come to be such 

 as it is; that is, how has it come about that there has been developed just that series of 

 nerve mechanisms which corresponds to the demands made upon the organism by its 

 environment?' He further indicates that in a progressive change of conditions of en- 

 vironment has originated a definite correlative change of function in the organism. 



Some may regard the foregoing questions as properly belonging to biological phil- 

 osophy and as having no practical significance, and their solution no practical utihty. 

 But let it be said that, had the answers to these seemingly purely scientific questions 

 been reahzed and regarded in time, they would have conveyed the solution of practical 

 fishery and fish-cultural problems which have for years been the subject of debate by 

 scientist, fish-culturist, and fisherman, and the object of inadequate legislation, to say 

 nothing of the research, inquiries, and fish-cultural effort that are still going on, as well 

 as continued and changing legislative action. 



