PACIFIC SALMON FISHERIES. 205 
A more modern method in use at many hatcheries, which has been 
well described by Mr. Bower,? is as follows: 
The long-followed process of taking Pacific salmon eggs by hand expression has been 
superseded in the last few years by the method of incision, a method discovered and 
developed by the late Cloudsley Rutter in connection with his study of the life history 
of the salmon of the Sacramento River. This consists simply of making a cut in the 
abdominal walls from the throat or near the pectoral fins to the vent, the fish just 
previously having been killed by a blow on the back of the head. When making the 
cut the knife is either shielded by a guard or is so held between the thumb and fore- 
finger as to allow not more than half an inch of the blade to project, thus precluding the 
possibility of injuring any of the eggs. Immediately following the incision the eggs 
flow in a mass into the spawning pan beneath. The operator’s fingers are inserted 
into the abdominal cavity gently to assist in removing any eggs that may be enfolded 
in the organs or that may merely adhere to the walls of the cavity. Fertilization is 
accomplished in the usual manner. 
Care must be exercised not to tear loose from the ovaries any eggs that do not come 
freely when the organs are moved from side to side by the fingers. Eggs thus torn 
loose are immature, and if taken it becomes necessary to eliminate them subsequently 
in the hatchery. It is preferable also to have the fish either in a vertical position or 
with the head considerably higher than the tail, that gravity may assist the flow of eggs. 
It was at first thought necessary—and the practice still obtains at some stations— 
to bleed the fish either by cutting off the head or tail before making the incision. 
Experimentation, however, has conclusively demonstrated that no advantage results 
from this procedure, as the few drops of blood that may occasionally fall into a pan of 
eggs result in no harm. The extra labor involved in bleeding may therefore be 
dispensed with entirely. 
When taken by the method of incision the eggs are of greatly improved quality; 
there is no straining or rupture of good eggs as is inevitably the result when heavy 
hand pressure is exerted: no unripe eggs are torn from the ovaries; and at the same 
time there is no waste of good eggs left enfolded in the organs, as is certain to be the 
case in stripping by hand. The improvement in quality is from 5 to 10 per cent and 
the saving in labor, too, is of noteworthy consideration. : 
The taking of Pacific salmon eggs by incision marks so distinct an advance in fish 
culture that it is no longer permissible to continue the obsolete method of stripping 
by hand. 
FERTILIZING THE EGGS. > 
In impregnating the eggs the main object is to bring the milt and the eggs together 
as quickly as possible after they have left the fish. By some persons a little water 
is considered desirable to give greater activity to the milt, but if left more than a 
minute in the water there is a decided loss of fertilizing power. The eggs do not 
suffer so quickly from immersion in water. The absorbing property which they 
possess when they first leave the parent fish, and which attracts to the micropyle the 
spermatozoa, lasts several minutes, but it is not prudent to leave the eggs in the water 
a moment longer than is necessary before adding the milt. 
The addition of the water is not essential to a good impregnation; in some instances 
better results are secured without the use of water and, after all, if the main object 
is secured, of bringing the milt and the eggs together with the slightest possible delay 
after they leave the fish, it makes very little difference whether water is used or not. 
The milt retains its fertilizing power several days when kept from air and water, and 
impregnation can be effected between fishes widely separated by merely forwarding 
the milt properly sealed. At Baird impregnation by the dry method, which has 
always been followed there, has resulted in the fertilization of about 90 per cent of the 
eggs so treated. 
The Russian or dry method of impregnating eggs consists simply in taking both the 
eggs and the milt in a moist pan. It may be urged as an objection to this method 
that the eggs will be injured by striking against the pan, but it is a fact that although 
the same eggs would be destroyed by the concussion a week later, or even 24 hours 
later, they do not suffer in the least from it at the moment of extrusion from the fish. 
It was at one time considered an important question whether the eggs or milt should 
be taken first, but with the dry method it makes no difference, as, either way, both 
eggs and milt remain operative long enough for all practical purposes of impregnation. 
a Fish Culture in Alaska, by Ward T. Bower. Jn Alaska Fisheries and Fur Industries in 1911, by 
B. W. Evermann. U.S. Bureau of Fisheries Document No. 766, pp. 80,81. Washington, 1912. 
>’ A Manual of Fish-culture, Based on the Methods of the U. S. Commission of Fish and Fisheries, 
revised edition, pp. 10-12, Washington, 1990, 
