582 
CHARLES WILSON GREENE 
mercial fishery interests in the lower Columbia River gave abun- 
dant opportunit}^ for the recapture of individual fishes, notwith- 
standing the broad expanse of territory necessary to be covered. 
Rutter marked his fish on the Sacramento River b}^ a method of 
branding with a hot iron, similar to that used for marking cattle 
on the plains in early days. Of some 150 fish branded by him, 
only three were afterwards re-taken an the Government Fisheries 
in the lower head water of the river. 
On August 4, 1908, I secured and marked with metal tags 59 
fish. These were immediately liberated in the river in good con- 
dition and in each case quickly swam out of sight. The fish 
were secured through the kindness of Superintendent Nicholay 
Hansen of the Chinook, Washington, Fish Hatching Station. 
Superintendent Hansen generously furnished transportation and 
facilities for taking and marking the fish. The fish were taken 
from the Washington State Trap which is located just above Sand 
Island about eight miles from the mouth of the Columbia River. 
This location was peculiarly favorable to the execution of the ex- 
periment. In the first place the spot is well within the mouth 
of the river, so that the average salinity of the water is only mildly 
brackish. It is also on the border land between the two great 
fishing fields utilized by the traps on the one hand and the gill 
nets on the other, thus giving the liberated fish a fair chance for 
a successful run. The location promised opportunity for deter- 
mining whether or not the fish might migrate back and forth 
through the estuary with the ebb and flow of the tides, since Rutter 
has advanced the theoretical view that such is the case. The later 
details will show that the location was especially fortunate with 
reference to this particular point. The salmon were run from 
the trap into a large live car used by the station. They were 
marked one by one from this car. 
The apparatus adopted for marking the fish in this experiment 
was the aluminum metal stock marking button used for marking 
domestic animals, — sheep and cattle. The button is adapted 
for insertion in the ear of sheep or other animals and can be riveted 
together in a way that makes it absolutely impossible to break 
it apart except by actually tearing it from its location. The 
