CONFERENCE ON SALMON PROBLEMS 



103 



Within certain limitations there is random 

 movement. 



Dr. ^Yard. May I point out that you 

 have to consider in Thompson's paper that 

 he entirely overlooked the fact that carp has 

 no opportunity for movement according to 

 Einstein's formula; they move within fixed 

 sides of a narrow stream and not as in a 

 field of equal movement in all directions. 

 While the movement of the fish in the drift 

 area might correspond very much more 

 nearly with Einstein's formula, the move- 

 ment of carp in a stream would meet limits. 



Dr. Huntsman. We tried to apply the 

 formula to salmon and came to the conclu- 

 sion that we could not expect it to apply 

 after a short time owing to space limitations 

 and the effect of river influence. 



Dr. Belding. Did Dr. Thompson elimi- 

 nate the question of food? Naturally the 

 movements of carp will be governed by the 

 distribution of food in the river. 



Dr. Huntsman. If the food is sufficiently 

 uniformly distributed the random effect will 

 not be obscured. 



ODORS 



Dr. Huntsman. From the facts we have 

 it is clear that the salmon show a definite 

 relation to their own rivers. Perhaps the 

 best speculation is that this is determined 

 by smell, and yet it seems as if nothing has 

 been done in this direction to determine 

 whether a fish can recognize the very many 

 odors that may exist in river water as dis- 

 tinguished from sea water. In Mr. White 's 

 experiment with the east branch of the 

 Apple River originally there were no young 

 salmon that he could find, and no local 

 salmon went up in the fall, although they 

 went up the other branch. But, when he 

 planted the Restigouche fry in that river, at 

 once that fall the local salmon went up and 

 spawned. It seems that the presence of 

 young salmon in the river determined 

 whether the local adults would or would not 

 ascend the river. It would be through some 

 odorous substance that came from the young. 



I raise the point that we need to have some 

 experiments or further observations made. 



Mr. Menzies. There is no doubt at all 



from the observations made that there were 

 no salmon in that river before his work? 



Dr. Huntsman. It is impossible to prove 

 a negative, but none were found. 



Mr. Menzies. He actually did find a num- 

 ber of native smolts in the river. You 

 would still have the lure of the salmon 

 scent. 



Dr. Huntsman. Smolts undoubtedly go 

 up as well as down; also they go up above 

 tidal water. Therefore, there is no more 

 evidence that the native smolts found later 

 came from one rather than the other river. 



This result of a preference being shown 

 for the branch with young salmon is quite 

 in accord with his experiments with the 

 marked fish. With both river waters there, 

 the fish ascended the one in which they 

 had been reared. 



Mr. Menzies. It is in keeping with the 

 salmon going back to their own river. 



Dr. Huntsman. In the matter of going 

 back to their own river, the unproved be- 

 havior is that when they are away from the 

 river influence. Of that I am still in great 

 doubt. 



Mr. Menzies. The home to a tributary 

 or the home to a river. 



Dr. Huntsman. Since the two branches 

 have separate estuaries that empty into a 

 common estuary, it will be necessary to de- 

 fine a tributary as including an estuary, if 

 these are not to be considered different 

 rivers. 



Mr. Cowie. The doubt exists when the 

 salmon are 20 to 30 miles away from the 

 mouth of the river. It would have to be 

 the influence of the river as a whole they 

 would have away out at sea. 



Dr. Huntsman. 1 have believed that 

 they might get back if random movements 

 could bring them under the influence of 

 their own stream. 



Mr. Coivie. Take the Pacific salmon, 

 there is a distinct difference in size between 

 the Rivers Inlet fish and the Fraser River 

 fish, the sockeye. There is even a slight 

 difference between Smith's Inlet and 

 Rivers Inlet, with a comparatively narrow 

 peninsula between the two. Yet each kind 

 goes back to the source from which it came. 



