PACIFIC SALMON FISHERIES. Bt5 
REARING SALMON FRY. 
For many years it was the custom to plant the fry as soon as they 
had absorbed the yolk sac, a period of about 30 days. <A few thou- 
sands were sometimes raised to the fingerling, yearling, or adult 
stage, moreyas a curiosity than anything else. No particular diffi- 
culty was experienced in raising these fish, but the expense entailed 
in feeding them for a prolonged period, and the impossibility of doing 
so unless large ponds were constructed at great expense for the pur- 
pose of holding them during the feeding period, prevented the general 
adoption of the rearing system. 
For some years certain fish culturists had contended that the plant- 
ing of fry just after they had absorbed the umbilical sac was an 
economic mistake, claiming that at this age they were weak and com- 
paratively sluggish in their movements, and would fall easy prey to 
their numerous fish, bird, and other enemies. The late Robert D. 
Hume, who built and operated a hatchery on the lower Rogue River; 
also one on the upper Rogue River, which the United States Bureau 
of Fisheries operated for some years, was one of the first to take up 
the rearing of salmon fry on any scale. 
In time these objections bore weight, and afew years ago the con- 
struction of ponds in which fry could be held and fed until they had 
reached a size which would insure them at least an even chance for 
their lives was undertaken all along the coast except in British 
Columbia, with the result that to-day there is pond capacity for about 
one-half of the total capacity of the various hatcheries. 
Most of the nursery ponds have been constructed near the hatch- 
eries and usually comprise oblong trenches dug in the earth and 
walled with cement and stone. 
In Oregon the State authorities found that the best results in pond 
rearing were obtained by using creek or natural ponds, which were 
made by placing dams across the small streams in the vicinity of the 
hatcheries. When first taken from the hatching troughs the fry are 
placed in the artificial ponds until the danger from spring freshets in 
the small streams is over, when the fry are transferred to the natural 
ponds, where the continual flow of fresh water, and the logs, rocks, 
etc., which provide shade and shelter, afford more natural conditions, 
and in which the natural food of the fry supplements the artificial 
food provided by man. 
The young fry show when they are ready to feed by darting to one 
side or the other when small particles of food are dropped in the water 
and float past them. For the first few weeks they should be fed 
regularly and as often as six times a day, and the earlier in the day 
the feeding begins and the later it continues at night the better. 
Two hours after feeding they will be found to be ravenously hungry, 
