102 



THE MIGRATION AND CONSERVATION OF SALMON 



grate at night. There are chances of catch- 

 ing them at dusk, then they will start to 

 move farther upstream. In the springtime 

 or really cold weather they only run for an 

 hour or two in the day time. 



Dr. Huntsman. This is the behavior ob- 

 served for smolts. With temperatures going 

 up to 60° and above, the smolt entered the 

 trap in the middle of the day as well as at 

 night. The next day with the temperature 

 not reaching 60° F. none entered in the 

 middle of the day. They have their great- 

 est activity in the evening. 



Mr. Menzies. Grilse will run up shallows 

 in very low water, but not unless you get a 

 strong southwest wind. 



Dr. Huntsman. Parr will stay in deep- 

 ish water during the day, but after sunset 

 they will be in the shallows with fins out of 

 water. 



Mr. Menzies. Strong southwesterly wind 

 is almost as good as night, when grilse com- 

 ing up with the tide and really fighting to 

 get over a shallow. 



Dr. Rich. Have you noticed any differ- 

 ence in the activity when the fish are just 

 coming out of brackish water as compared 

 with the movements after they are well up 

 into fresh water ? 



Mr. Menzies. No. 



Dr. Rich. There is a distinct difference 

 in the streams on the west coast with regard 

 to the migration of red salmon coming up 

 from brackish water. They start to run 

 early in the morning at a place where we 

 had a weir and were counting them, and in 

 the evening they stopped in a matter of five 

 minutes when the sun got down behind a 

 certain hill, 



TURBULENT CURRENTS 



Dr. Huntsman. This subject will not be 

 at all clear without a great deal more work. 

 Its importance is, I believe, very great. You 

 get such results as, if a salmon is moving 

 about and comes into a current with turbu- 

 lence it orients itself and is liable to remain ; 

 without such it becomes active, even to the 

 extent of jumping out of the water. 



Mr. Menzies. What happens when there 

 is no turbulent current ? 



Dr. Huntsman. It shows no orientation 

 at all. It may be moving about, going to 

 and fro. It seems to be restless when away 

 from such turbulent current. 



RANDOM MOVEMENT VS. DIRECTED MOVEMENT 



Mr. Menzies. Our marking experience 

 does not suggest that the movement is quite 

 at random. 



Dr. Huntsman. The movement may be 

 directed or it may be at random. I cannot 

 see direction in it. It is desirable to have 

 the facts on which is based the view that it 

 is directed. If it is a to and fro movement, 

 I would not call it directed. 



Mr. Menzies. There surely must be direc- 

 tion. Of fish marked close to the mouth of 

 the river, some are 36 days later caught at 

 the same place, while another on the follow- 

 ing day is caught three miles away. Other- 

 wise it would be just chance movement. 



Dr. Huntsman. It might be of interest to 

 refer to a paper by Thompson on tagging 

 data for the carp in the Illinois River. The 

 only direction which he got for the carp was 

 that there was a greater tendency to go 

 downstream. He found the spread of the 

 carp through the water to correspond with 

 the formula of Einstein for Brownian move- 

 ment of inorganic particles. 



Dr. Belding. Several tagged fish were re- 

 captured after 28 to 36 days, in the Mira- 

 michi drift-net fishing area. The salmon 

 evidently move around in this area, their 

 movements being governed in part by the 

 local currents and weather conditions. 

 While they probably did not leave this area 

 they actually travelled a considerable dis- 

 tance in their random movements. 



Dr. Huntsman. On the Margaree coast, 

 on the basis of the results of recaptures of 

 tagged fish, if seemed that in about two 

 weeks those that were tagged just outside 

 the river were uniformly distributed among 

 the stock of salmon that occupied that area. 



Mr. Menzies. Surely that was directed; 

 the river must exercise some control over 

 their movements. 



Dr. Huntsman. River influence restricted 

 them ; as soon as they got to the edge of that 

 influence their extension tended to stop. 



