6 U. S. BUREAU OF FISHERIES 
process repeated until all the good eggs are procured. If the eggs 
do not start readily they should not be taken. 
As soon as one female is stripped the milt is added, care being taken 
all the time to allow no water in the pan until the lot is finished or 
until the pan is half or two-thirds full of eggs. If males are abun- 
dant one is stripped for each female, and one for every two or three 
females in any event. When the pan is about half full, and before 
any water is added, the eggs are very thoroughly and carefully 
stirred with the outstretched, spread fingers, enough water is added 
to cover the eggs nicely, the whole being mixed again with the fingers 
and allowed to stand for two minutes. Next the milt of one or two 
more males and a little water are added, the mixture is stirred as 
before, and again allowed to stand for five minutes. 
Impregnation can not take place unless the milt and eggs come into 
perfect contact, and as the milt dies two minutes after water is added, 
and as the eggs will not become impregnated after having been in 
water six minutes, it can readily be seen that the eggs and milt must 
be thoroughly and quickly mixed, both before and after the water is 
added. <A tablespoonful of muck solution or cornstarch is now 
stirred into the mass and a pint of water added. The water is 
poured off after standing, and this process is repeated every half 
hour, as described on pages 15 and 16. 
After the adhesion has subsided the eggs are placed in a keg nearly 
filled with water, and stirred every half hour, with a change of water 
at least every hour from the time the eggs are taken until they are 
delivered at the station. The stirring is thoroughly, but gently, done 
with a dipper, care being taken that the dipper does not strike the 
sides or bottom of the keg. 
The eggs should never be exposed to the sun, and the water sur- 
rounding newly taken eggs should preferably be kept between 40° 
and 50° F., though experience has shown that even 35° is not 
harmful. Of course, all sudden changes of temperature should be 
avoided. 
PENNING ADULT FISH FOR COLLECTION OF SPAWN 
The plan of holding, in pens or other inclosures, adult fish taken 
prior to the spawning season has been tried with some success. This 
may be done to insure a sufficient and definite number of spawners, 
the collection of which during the fishing season is frequently inter- 
rupted by stormy weather or other causes. The method is sometimes 
followed at collecting stations where commercial fishing for the 
species is not followed and where many of the fish taken for cultural 
purposes have not fully matured their sexual products. 
Contrary to expectation, pike perch proved more difficult to han- 
dle in this manner than most of the other species to which the 
method has been applied. Perhaps the higher water temperature 
at the time the work is conducted is an influence. The fish must not 
be crowded either while being transported or at any time during 
their confinement. Where injuries have occurred fungus is likely 
to set in much earlier than with the whitefish, and on this account 
great care is necessary in handling pike perch, as well as to prevent 
injury to eggs in the ovaries. While the male whitefish can be held 
