SCALES OF THE SPRING SALMON 27. 
_SESSIONAL PAPER No. 38a 
check to the next summer’s growth is as abrupt as in older fish. The fry are about 
1-5 inch long when they migrate, and the average length at the end of the year is 
about 10 inches. (Here as elsewhere in this paper the caudal fin rays are not 
included when the length is measured.) Some measurements, given in inches, will 
give some indication of the rate of growth: August 18, 5.0 (2), 5.2, 5.5 (2), 6.0, 6.5, 
7.5; November 6, 10.0; December 4, 8.7; December 26, 9.7; January 28, 10.0; Febru- 
ary 11, 10.2; March 3, 10.7; March 6, 10.2; March 11, 8.8; Aprl 3, 8.8; April 6, 
11.4, 8.7; April 8, 11.6; April 13, 10.4; April 14, 10.2. After this date the rapid 
growth had started in all the specimens examined. At this time the fish is about a 
year old, or slightly more, and weighs about half a pound. In the measurements 
given later the first year is taken to be the period to the end of the first winter check. 
Concerning the later growth it is not necessary to say very much. Broad’ summer 
bands are followed in succession by narrow winter bands. In normal individuals 
the limit of variation is not so very great, but naturally it increases with the age of 
the fish. At the end of the second year the average length of the fish examined was 
20-5 inches, and the weight somewhat over 4 pounds. At the end of the third year 
the length was 28.5 inches, and the weight 14 pounds. At the end of the fourth year 
the length was about 33 inches, and the weight 22 pounds. No specimens obtained 
had completed the fifth year. 
The fry that remains in fresh water during the first year starts to develop the 
scale about the same time as the one that goes to sea, but as the fish in fresh water 
grows very slowly, the scale grows slowly also, and the rings, even in the summer 
time, are quite close together. In the winter they come almost together and are 
cften incomplete or broken. The winter check can be distinguished more readily 
in the majority of specimens, by the narrow area of broken lines than by judging 
the distance between the lines. The fish is still under 4 inches in length, and hence 
does not compare at all favourably with the one that spent its first year in the sea. 
Usually the migration to the sea is made early in the spring, so that the growth in 
salt water is indicated immediately following the winter check. In some instances, 
though, there is indication of a small amount of fresh-water growih outside of the 
winter check before the growth in salt water commences, but it never reaches an 
extent similar to that sometimes found in the coho. About one-third of the specimens 
examined showed evidence of this growth. It would seem then that a large majority 
—two-thirds of the whole number in this group—migrate early in the spring, in 
March or early in April, and the remainder follow not so very long after, so that by 
tue middle of May, or even earlier, the last stragglers must have disappeared from 
ibe fresh water. 
After the seaward migration the growth in this type is entirely comparable to 
that in the other. At the end of the second year the average length is nearly 14 
inches, and the weight slightly over a pound; at the end of the third year the length 
is over 23 inches and the weight 6 pounds; at the end of the fourth year the length 
is 30 inches and the weight 16 pounds. Sixth year’ specimens were lacking in this 
type also. 
In making a more detailed analysis and comparison, the following data were 
obtained. Of 306 fish over one year old examined, 199 or 65 per cent of the whole 
number had migrated as fry. Of these, 83 were in the second year, 43 in the third, 
59 in the fourth, and 14 in the fifth year. Of the 107 that stayed in the fresh water 
_a year, 10 were in the second year, 18 in the third year, 44 in the fourth, and 35 in 
the fifth. The growth of each fish in each year has been calculated and the average 
for each year taken. The following table was made out for the purpose of comparison. 
