208 PACIFIC SALMON FISHERIES. 
house, and placed in the troughs. Others pour the contents of the several pans— 
eggs, milt, and all—into a large can after the eggs become impregnated, and when the 
eggs separate the contents of the can are poured into the hatching troughs, trusting 
to the current in the troughs to wash the milt from the eggs. At Baird. water is poured 
on the eggs a few moments after they become impregnated, after which they are left 
perfectly quiet until they separate, which, in water of the temperature of the McCloud 
River in September, 52° to 53°, takes about an hour. The pans, in the meanwhile, 
are put in a trough filled with river water to keep them from becoming too warm. 
After the eggs separate they are carefully washed and are carried in buckets to the 
hatching house, where they are measured and placed in the hatching trays. 
Mr. Bower? has the following to say as to the loss by concussion 
and the proper method of preventing same: 
Coincident with the absorptive period in salmon eggs is an adhesive stage varying 
with the temperature from one to two hours, when the eggs are exceedingly sensitive. 
This is the so-called period of water hardening. Under no circumstances should the 
eggs be handled during this stage, nor should they be subjected to the slightest con- 
cussion. Repeated tests have demonstrated conclusively that even allowing the 
buckets containing the eggs to stand on the same platform where spawning operations 
are being carried on results in considerable loss. 
To guard against this, the buckets should either stand on the bottom of the stream 
or else on a platform in every way independent of and having absolutely no connec- 
tion with the main platform. To some this may seem like a small and irrelevant 
consideration, but strict observance is certain to reduce the loss by at least 2 or 3 per 
cent. During the process of water hardening the buckets should be partly sub- 
merged to properly regulate the temperature. 
Due caution must be observed not to move the eggs until water hardening is com- 
plete. After a little experience the operator can readily tell, upon carefully inserting 
the hand and finding the eggs free and hard and no longer soft and velvety, even 
toward the bottom of the bucket, that they may be moved to the hatchery without 
fear of loss. 
HATCHING APPARATUS AND METHODS.? 
The hatching apparatus generally employed on this coast is 
pretty much of the same pattern and is described as follows:¢ 
The hatching apparatus generally employed on the Pacific coast in salmon propaga- 
tion consists of a combination of troughs and baskets. The troughs in common use are 
the so-called ‘‘Williamson troughs,’’ which are 16 feet long, 12, or 16 inches wide, 
and 64 inches deep. The troughs are arranged in pairs, and usually two or three 
pairs are placed end to end on different levels. The fall of water in each trough is 14 
inches. The troughs are divided by double partitions of wood or metal into com- 
partments just enough longer than the baskets to enable the latter to be raised and 
lowered and to be tilted slightly. The essential feature of-these troughs is that at 
the lower end of each compartment a partition, extending entirely across the trough, 
reaches from the bottom almost to the top, and another similar partition at the upper 
end of the compartment reaches from the top almost to the bottom of the trough, 
each set of partitions being about an inch apart. The water is consequently forced 
to flow under the upper partition and over the lower partition, and to do this it must 
pS ei eee ee ee a ee Ee ee 
a Fish culture in Alaska, by Ward T. Bower. Alaska Fisheries and Fur Industries, 1911. United States 
Bureau of Fisheries, document no. 766, p. 81, 82. 
b At some of the Alaska hatcheries quite large baskets, some holding as many as 103,000 red-salmon éges 
are used. 
¢ Manual of fish culture, based on the methods of the United StatesCommission of Fish and Fisheries, 
revised edition, p. 12, 13. 
