NATURAL HISTORY OR THE QUINNAT SALMON. 
137 
ova were found in the stomach of a trout taken in Mill Creek December 1, 1901, several 
days after any artificial spawning had been done at the station. As there were several 
salmon spawning in the creek at that time, there is little doubt that the eggs were 
secured from natural spawning-beds. Trout are adapted to catching floating objects 
and are doubtless very destructive to salmon spawn where the salmon breed naturally. 
Other fishes, such as the hitch ( Lavinia ), hardhead ( Mylopharoclo n ) , and sucker 
( Catostomus ), have not been found to eat salmon spawn, though they probably do; 
the black-fish ( Orthodon) has not even been found near the spawning-beds. A large 
Sacramento pike ( Ptychocheilus ) that had secured spawn from natural spawning- 
beds was taken in the river near the mouth of Battle Creek in 1900. 
Natural versus artificial propagation. — Probably the most important problem 
yet remaining unsolved in connection with the natural history of the salmon is the 
efficiency of natural propagation. If we could segregate a certain number of fishes 
in a small stream, then put a fine screen across below where they are to spawn, and 
later catch all the alevins and fry produced, we could solve the problem. But a 
small stream, such as could be experimented with, is liable not to have an average 
number of fishes to prey upon the spawn and alevins, and the conditions would not 
be entirely natural. The following statement represents approximately the com- 
parative value of natural and artificial propagation : 
Percentage of loss in 
Items. 
propagation. 
Natural. 
Artificial, 
Not spawned ... 
1 
«1 
Unfertilized 
15 
2 
Killed before hatching 
^70 
8 
Alevins killed 
ft 13 
c 2 
Total loss.. 
99 
13 
« 10 to 20 per cent if unspawned eggs are not removed by abdominal section. 
b No definite data 
c At least 50 per cent if alevins aie planted. 
From the foregoing it will be seen that the heavy loss in artificial propagation 
has been in not spawning all the eggs and in planting alevins, both of which can be 
remedied, as is elsewhere shown in this report. The total loss in artificial propaga- 
tion should not be 15 per cent. 
There is a much greater loss when alevins are planted artificially than when 
they hatch out naturally. 
(а) From a given number of ova, as those produced by one fish, which is the 
basis of the percentage, there are more alevins to be destroyed in the case of artifi- 
cial propagation. In natural propagation they have been already largely destroyed 
before they become alevins, and there are not 87 per cent left to be destroyed, as in 
the case of artificial propagation. 
(б) But even with a given number of alevins the percentage is greater in artifi- 
cial planting It is not possible to scatter them as well in artificial planting as in 
natural propagation. No amount, of care will prevent their collecting in bunches, 
which has not been seen in natural propagation. 
Something of the value of artificial propagation can be learned from an experi- 
ment tried at Clackamas hatchery, Oregon. In March, 1896, 5,000 salmon fry 2.5 
inches long were marked by cutting off the adipose fin. The eggs from which the 
fry were hatched were spawned .at Baird hatchery in September, 1895. Mr. Hub- 
