Foster. — White Perch Propagation 163 



eggs from a female. Ripe eggs not secured will be naturally- 

 deposited in the pounds during the ensuing night. A number of 

 females, weighing about a pound each, had every appearance of 

 being spent but upon being opened were found to contain immature 

 eggs and probably would not have spawned for at least a month. 

 Their resemblance to spent fish was so marked as to deceive 

 experienced fish culturists. 



If the eggs cannot immediately be transferred to the hatchery 

 after water-hardening, they should receive a change of water at 

 least once an hour and the temperature kept as even as possible. 



White perch eggs may be hatched in either open or closed top 

 jars, the Downing jar being preferable. When the eggs are 

 received from the field, they are passed through a bobbinet screen 

 and from 12 to 15 ounces measured to each jar. The eggs do not 

 circulate as satisfactorily as those of the shad or pike perch. The 

 flow of water is adjusted to give as good a boiling motion as possible 

 without flowing the eggs out of the jar. 



The eggs are somewhat heavier after being held for a day in 

 the jars and after eyeing will require a greater flow of water 

 than when first measured up. It was formerly customary to 

 replace open-top with closed-top jars after the first 12 hours, but 

 an increased flow of water through the open top jar is equally as 

 satisfactory. 



It is impossible to separate the good and bad eggs while they 

 are in the jar so that siphoning is impracticable. The eggs are 

 extremely susceptible to fungus and, unless of exceptionally good 

 quality, it is advisable to remove the fungused bunches, by 

 screening through bobbinet, at least twice during incubation. 

 The bunches from the first screening are thrown away, but from 

 the second, which is usually done after the eggs are eyed, they are 

 placed in "hospital" jars and will produce many fish. Should 

 the eggs in these jars stick together in a mass and stop circulating, 

 it will be necessary to close down the jar and stir the egg mass 

 with a feather every half hour, until hatching is completed. 



Eggs of good quality taken from fish held but a few hours 

 in nets or pens, and properly fertilized and cared for in the field, 

 will give little trouble and hatch fully 95%, while inferior eggs are a 

 source of much annoyance and no amount of care during hatching 

 will produce satisfactory results. There is practically no difference 



