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POPULAR SCIENCE MONTHLY. 



The diagrams indicate the passage of the fry from the fall run 

 of adults; those from the summer run passed the upper station 

 earlier, some of them being noted at Battle Creek during October and 

 November. Observations in 1900 show that they may begin migrating 

 in September. 



The work at Balls Ferry indicates that the greater part of the 

 young salmon passed that portion of the river between the middle of 

 January and the middle of March. Practically all had passed by 

 March 20. Numerous measurements made at frequent intervals show 

 that the daily average size varied but one tenth of an inch during the 

 three and a half months. The average of all measurements is 1.53 

 inches. This confirms the inference from the Battle Creek work that 

 practically all the fry begin their migration as soon as they are able 

 to swim, otherwise the later ones would have been larger. 



Both diagrams show that a big run of fry is not necessarily coinci- 

 dent with a rise in the river. From the Walnut Grove diagrams we 

 note. From the middle of January to the middle of May there 

 were salmon fry in various numbers passing Walnut Grove. The 

 height of the migration was from March 4 to about the 24th, lasting 

 about 20 days. Practically all had passed by April 22. The size of 

 those taken during January was l.G inches, during February 1.8 

 inches, during March 1.7 inches. From March 30 to May 7 they 

 increased from 1.7 inches to 3.0 inches. The field notes show that as 

 many fry were taken during the day as at night. The water of this 

 portion of the river is muddy. 



Comparing the two diagrams we note that a large run of fry passed 

 Balls Ferry February 2, and that 34 days later, March 8, there was a 

 large run of fry passing Walnut Grove. Again, a large run passed 

 Balls Ferry February 14, and 34 days later, March 20, there was a 

 large run passing Walnut Grove. The later Balls Ferry runs were 

 caught by the high water the last of March, and their passage was not 

 noticed at Walnut Grove. The high water probably carried them down 

 faster, and they may have passed while the trap was out of the water, 

 March 23 to 26. 



