PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1922. 47 



mittedly crude, that are used to prevent cohesion are also responsible 

 for a certain percentage of the mortality ; and that extreme care in 

 the stripping process and in the application of the means to overcome 

 cohesion may reduce the loss to a considerable extent. 



PBOPEB METHODS OF TAKING, Fi:BTILIZING, AND CARING FOR EGGS OF WHITEFISH 



AND CISCO. 



Every year an increasing number of fishermen undertake to secure 

 for delivery at the hatcheries the mature eggs of the fish taken in 

 their operations. In certain remote sections of the Great Lakes eggs 

 that they are unable to deliver at a hatchery are taken and fertilized 

 by fishermen. Every possible effort is made to furnish a boat or 

 other means for transporting all eggs secured to the nearest hatch- 

 ery, but with the limited facilities at present available it can not 

 always be arranged to visit all points where eggs are available within 

 a reasonable time, hence the fullest value of this cooperation is not 

 always realized. As the value of eggs for artificial propagation de- 

 pends to a considerable extent upon the methods used in obtaining, 

 fertilizing, and caring for them prior to their installation in a 

 hatchery, tlie following suggestions are offered for the advice of 

 interested persons: 



The prospective spawn taker should have a pan, a dipper, and a 

 number of wooden kegs or cans in which to place the eggs after 

 fertilizing them, these articles to be supplied from the nearest hatch- 

 ery. As soon as spawning fish are available rinse and drain the pan, 

 wipe the excess water and slime from a female fish by passing the 

 hand gently over the abdomen. Hold the fish as close to the pan 

 as possible and express the eggs from it by gentle pressure, working 

 from just above the pectoral fins toward the vent. Eggs that are 

 ripe and in condition for incubation will flow freely from the fish 

 under slight pressure, and only such eggs as are obtainable without 

 the use of force should be taken. After stripping the female the 

 milt is expressed on the eggs by a similar manipulation of the male 

 fish. To insure the contact of all eggs with the milt, they are gently 

 stirred with the naked hand or by a carefid movement of the pan. 



The process of alternately stripping females and males is con- 

 tinued, with frequent stirring, until the pan is about half full, when 

 the contents are carefully transferred to a transportation can or a 

 keg, which has been previously half filled with water. In making 

 the transfer do not subject the eggs to the drop incident to pouring, 

 but lower the pan into the water before emptying. If this is im- 

 practicable, the same result may be accomplished with the dipper. 

 As the eggs increase nearly 100 per cent in size shortly after fertiliza- 

 tion, no more of the newly taken eggs than will fill the keg one- 

 quarter full should be placed therein. If more than this amount is 

 placed in the keg, loss of eggs from suffocation will result, as the 

 eggs attain the greater part of their increase in size during the 

 water-hardening process. As the eggs at this time have a strong 

 cohesive tendency, it is necessary to agitate them at frequent intervals 

 by stirring gently with the hand. 



As soon as all eggs available for the day have been taken those 

 on hand should be washed. This is done by pouring off and renew- 



34223°— 23 i 



