90 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
The record also shows that ordinarily the young salmon travel at night. The 
trap was so set that they could not have avoided it had they traveled during the 
day. That they can he caught during the day is proved by their being taken in the 
open tow net set in Hatchery Creek, as noted above, under “Planting fry from 
the hatchery . ” F ry were seen quite often lying in a pool near the shore during the day, 
and were seen to rise to small insects that lighted on the water. They probably feed 
more during the day, which makes their migration slower, or stops it altogether. 
On November 30 there was a rise in the creek and the water was muddy. The 
catcli from 8 to 0 a. m. was larger than the average night catch at other times, showing 
that high and muddy water induces salmon fry to travel during the day. This fact is 
borne out also by the work at Walnut Grove, an account of which is given below. 
The great variation of the catch when the net was set for an hour or two during 
the night indicates that they travel in schools. » 
A trap similar to that used in 1898 was set in Battle Creek in 1900 from Septem- 
ber 13 to October 4. Salmon fry 1.5 inches long were taken, two or three at a time, 
from September 18 on. The downstream migration, therefore, begins at least as early 
as the middle of September. 
Adult salmon can be found in some part of the river throughout the year, and 
the spawning season is therefore very long. It is probable that there are salmon 
spawning at some place in the river or its tributaries in every month of the year. 
They are spawning in considerable numbers from July till January, inclusive. With 
such an extensive spawning period, it is obviously difficult to separate the young 
according to size, and say that t hose of a certain size belong to the spring or fall run 
of a certain year. A variation in rate of growth, noted elsewhere, adds to the difficulty. 
However, in the following table of measurements of specimens taken with the 
seine at Battle Creek fishery during October and November, 1898, three sizes may 
be distinguished, which doubtless represent three runs of adults. Those from 
1.4 to 2.2 inches in length were from the summer run of 1898; the 3.7 to 4.7 inch 
specimens from the fall of 1897 (and they doubtless were among the last to hatch); 
and the 6.2-incli specimens an earlier run, probably the summer run of 1897. 
Measurements of young salmon taken ■ with the seine. Battle Creek, October 18 to December 1, 1898. 
Size. 
No. 
Size. 
No. 
1 
13 
1 
1 
1 
3.9 inches 
1.5 inches 
1 inches 
4.1 inches . 
1 
4.2 inches 
1.8 inches 
4.3 inches 
4.4 inches 
2 
1 
2 
1 
2 
None. 
2 
4.5 inches . 
2.1 inches 
.2 
1 
None. 
1 
4.6 inches . . 
2.3 .to 3. 6 inches 
4.8 to 6.1 inches 
Balls Ferry station . — An observation station equipped with a trap similar to that 
used at Battle Creek fishery was established on the river at Balls Ferry, about 3 
miles above the mouth of Battle Creek. Observations were made by Mr. Chamber- 
lain, beginning January 6 and closing April 25, 1899. The following table gives the 
data obtained at this station. 
