Dec. 30, 1911.] 
FOREST AND STREAM. 
935 
platform, the tip of its nose was allowed just 
to touch the vertical piece and its tail was ex¬ 
tended to full length. The total length was then 
read off by the measurer and announced to the 
recorder. The tail was, however, never released 
from the grasp of the operator during this move. 
A struggle is apt to begin at any moment, and 
if the fish struggles, it must be swung free into 
the air to prevent pounding on the board and 
injury to itself. If the length was not caught 
by the measurer before struggling occurred, the 
process, of course, had to be repeated. Lifting 
a salmon from the water, taking it from the net 
and reading its length on the measuring board 
really consumed only a very few seconds. 
The next step was the insertion of the mark¬ 
ing button. This was done by the person who 
did the measuring. The buttons in this experi¬ 
ment were all inserted in the caudal fin. The 
salmon that came through the marking process 
in good condition were immediately released 
overboard in the direction of the open water. 
If there was any questionable degree of asphyxia 
the fishes were released into the car and turned 
overboard only when fully recovered. In two 
fishes that were markedly asphyxiated it was 
necessary to use artificial respiration for a short 
time. Both were strong and active when ulti¬ 
mately released from the live car. The fishes 
took the water readily and quickly swam away. 
My previous experience in handling live salmon 
enables me to state that the present handling 
was well within the limits of treatment which 
salmon endure without danger or risk. 
The weight of the fishes was estimated by 
Foreman Borkman, who has a reputation for 
skill in the accuracy of his judgments. Mr. 
Borkman's estimates have come very close to 
the actual weights of certain of the fish retaken. 
In at least one of the largest fish the actual 
weight tallied exactly. The judgments of the 
weight were arrived at during the handling of 
the fish in the net and on the measuring board. 
These estimates are only of relative value, how¬ 
ever, as indeed are the measurements of length 
in this preliminary test, and no calculations are 
to be based on either set of measurements. 
Of the fifty-nine fish marked and liberated on 
Aug. 14, there were twenty-five chinook salmon 
(Oncorhynchus tschawytscha ), sixteen silver 
salmon (O. kisutch), and eighteen steelheads 
(Saimo gciirdneri). These fish ranged in total 
length from forty-one to one hundred and three 
cm. for the Chinooks, forty-seven to seventy- 
eight cm. for the silvers and seventy-one to 
ninety cm. for the steelheads. The largest 
chinook weighed thirty-five pounds, and were well 
distributed as regards size. 
Information as to the import of the experi¬ 
ment was given out to the fishery interests on 
the Columbia. Fishermen were requested to 
record the place and details of the catch of 
any marked fish, to note any injuries or other 
facts of interest, and to report the same to me. 
Fishermen were also requested to send in the 
marking buttons with the tails of the fish. The 
various salmon packing firms were especially 
helpful in reporting catches and in forwarding 
the marking buttons. 
Seventeen out of the fifty-nine fish marked 
were retaken and reported to me. This number 
retaken represents 29 per cent, of the fish liber¬ 
ated, a very favorable proportion considering 
the twelve to fifteen days of closed season fol¬ 
lowing the 25th of August. Of these fish six 
were Chinooks, six were silver salmon and five 
were steelheads. The time of the retaking ex¬ 
tended from the date of the marking, Aug. 14, 
to Oct. 10, a total of fifty-seven days. Six were 
retaken nearby, four within seventy miles, and 
the others 210 miles away. 
Of the eighteen steelheads marked, only five 
were retaken. One of these was caught down 
the river four miles below where it was liberated 
and between four and five hours after liberation. 
As already stated, the fishes were liberated on 
a strong flood tide, and it is evident that this 
particular fish at once made about a mile an 
hour speed toward sea. It was taken by purse 
seine in the channel near Republic spit in the 
same locality where chinook number 123 was 
captured six days later. These two fishes give 
absolute proof of down-stream movements 'of 
salmon. The fishing annals of the lower Colum¬ 
bia have many instances of similar outward 
movements of schools of salmon. 
It is said that at certain times, following a 
period of stormy weather or when for other 
reasons the gill nets have not been operating on 
the lower river, the seines on lower Sand Island 
capture fish with definite marks received from 
fishing gear—marks that can be accounted for 
only on the theory that the fishes have moved 
seaward after receiving the marks. 
One steelhead was reported captured in a trap 
only about one-half mile up-river from the State 
trap where it was liberated. This fish was out 
seven days, but its button number was not taken. 
Rutter branded a number of salmon on the 
Sacramento River in September, 1900, at Rio 
Vista, which is above the salt water tides of 
the river. Three of these fish were retaken, two 
at the Mill Creek hatchery and one at Battle 
Creek. They covered the distance in an average 
speed of four to five miles per day. This speed 
was exceeded by six of the marked fish in the 
present experiment, these six making an average 
individual speed of from 6.36 to 7.50 miles a 
day with a general average of 6.8 miles. 
Rutter has advanced the theory that salmon 
make the journey through tide water by running 
up during the ebb and down during the flood 
tide, stemming the current each way. He ap¬ 
plied this principle in his studies of the chinook 
salmon of the Sacramento River. Following the 
variations in the catch of the fisheries .at the 
different towns along the bay and lower Sac¬ 
ramento, he estimated that a school of salmon 
made its way from Vallejo, on the lower bay, 
to Sacramento, on the river, in four days for 
the spring run when the river is relatively high. 
In the summer and fall they move more slowly. 
This he explains by the fact that the river is 
low and the tides in the bay therefore more 
nearly equal in time, thus requiring more time 
for the salmon to pass through the bay. 
My fish were marked in August, hence are to 
be compared with the movements of fall fish 
as described by Rutter. I accept Rutter’s hypo¬ 
thesis as partially explaining the movements of 
salmon in tide water. Undoubtedly currents in 
the rivers are directive on the movements of the 
migratory fishes. In tidal waters this factor is 
still active. In the tidal area at the mouth of 
a river the relative time of the flood and ebb 
currents rapidly changes toward the upper tidal 
limits, where the former entirely disappears. If 
salmon were directed by' currents alone, they 
would make the journey more and more continu¬ 
ously as they come within the brackish area. 
Figured on the basis of the difference of the 
duration of the flow of the flood and ebb cur¬ 
rents as against the observed speed of salmon, 
it is obvious that the fish would pass through 
the tidal area in a much shorter time than these 
observations indicate. Other factors are opera¬ 
tive, for currents alone are not sufficient to ac¬ 
count for the movements. I believe that a much 
more influential factor is the condition of the 
water as regards its amount of salt. Salmon 
are sharply responsive to the stimulus that comes 
from variation in the degree of admixture of 
sea water and river water in the tidal area, a 
stimulus that is doubtless in the nature of a 
negative chemotaxis. Attention has already been 
called to the changes in the osmotic equivalents 
of the blood in fresh-water salmon as compared 
with those in sea water. These changes, though 
slight, are due in large measure to the transi¬ 
tion from a sea-water environment to one of 
fresh water. Such physiological adaptations re¬ 
quire a relatively long time. If a salmon enter¬ 
ing the mouth of the Columbia should swim into 
an area of water relatively fresh before his gills 
and other epithelial tissues were sufficiently 
adapted to it, chemotactic reaction would stimu¬ 
late him to increased activity, which, by the law 
of such reactions, would lead him in the end 
toward salt water. These journeys into areas 
now relatively fresh, now relatively salt, but in 
the balance ever toward fresh water, will con¬ 
tinue until the epithelial tissues of the individual 
fish have become adapted to life in fresh water. 
The rate at which this adaptive process takes 
place determines the total time required for the 
passage through the tidal area. The observa¬ 
tions recorded in this experiment indicate a very 
much longer time spent in tide water by the 
salmon on the Columbia River than allowed by 
Rutter for salmon on the Sacramento. While 
not numerous enough and not sufficiently varied 
to make the deductions absolutely conclusive, yet 
these experiments strongly indicate that salmon 
spend not less than from thirty to forty days 
in passing the tidal area of the lower Columbia. 
SUMMARY OF CONCLUSIONS. 
Remembering that this experiment is prelimi¬ 
nary, and that the observations are entirely too 
few to make the deductions conclusive beyond 
question, still the following tentative answers 
may be given to the questions announced in the 
beginning of this paper. 
1. Salmon may take from thirty to forty days 
to pass through the brackish water within the 
limits of the fishing waters at the mouth of the 
Columbia River. 
2. That salmon spend considerable time swim¬ 
ming back and forth in tide water during the 
acclimatization to fresh water is indicated (a) 
by the fact that two fishes were taken below the 
point at which they were marked, (b) by the 
corrosion of the aluminum marking buttons by 
salt water, and (c) by the long time spent in 
reaching the lower limits of fresh water. 
3. When wholly within fresh water, the silver 
salmon and the steelhead make the migratory 
journey at an average speed of from 6 to 7 
miles a day and probably more. 
4. There is little evidence that the process 
of marking or that the partial obstruction of the 
course by fishing gear does more than produce 
a temporary checking of the migratory journey. 
