BULLETIN OF THE UNITED STATES FISH COMMISSION. 113 



Vol. IT, |Vo. 8. Washin$?ton, D. €. April S3, 1 884. 



50— I^'STKUCTiOi'VS FOR TAKIIV« WHITE-FISH EGGS. 



By SEYMOUR BOVVER. 



Employes engaged iu collecting white-fish eggs for United States Fish 

 Hatchery at Alpena, Mich., are desired to observe the following in- 

 structions : 



Care should be taken to use live, ripe fish only. The spawners are 

 ripe when they discharge their eggs freelj', in a liquid stream, when 

 pressed along the belly towards the vent. The males are ripe when 

 they yield the male principle or milt promptly by stripping with the 

 thumb and fingers just forward of the vent. The ripe females can quite 

 easily be distinguished from those that are not ripe, simply by touching 

 the belly, the former being very soft and the latter more or less hard. 

 In cases of doubt, however, it is well to take up the fish and try to start 

 the eggs by crowding ; if ripe, the eggs will flow freely with a moderate 

 pressure; if unripe, they come away, if at all, in bunches. Fish from 

 which the eggs are running when taken from the net are in perfect spawn- 

 ing condition (if alive) and may be manipulated at once. 



White-fish from trap-nets usually live twenty to thirty minutes after 

 lifting, sometimes much longer, according to the weather ; but the males 

 are too far gone for use whenever the milt is clotted or too thick to mix 

 freely with the eggs. Whenever there is a scarcity of male fish good 

 milters may be laid aside a few moments and then used a second time. 

 Milt mixed with blood should not be used. 



To hold a fish securely, place its head between the left arm and side, 

 and grasp it firmly with the left hand just forward of the tail ; this leaves 

 the right hand and arm free to press out the eggs and milt. Hold the 

 vent of the female close to the bottom of the pan, so that the eggs will 

 not be injured in dropping; then, with the whole hand adapting itself 

 to the natural curve of the belly, press or crowd slowly forward towards the 

 vent, repeating the movement until the eggs are all discharged, or cease 

 to flow freelj'. Then add the milt from two or more males as soon as 

 possible, and mix thoroughly, but carefully, with a feather or the tail of 

 a fish. Another si)awner may now be stripped into the same pan, and 

 milted as before, if there is one near at hand so that it can be done with- 

 out delay ; then set the pan aside and continue to take eggs as before, 

 in another pan, and so on. Allow each pan of milted eggs to stand not 

 less than two nor more than five minutes ; then add water until the pan 

 is about two-thirds full. In very cold weather, however, it is sometimes 

 necessary to add the water to the eggs immediately after milting, to pre- 

 vent freezing. About fifteen minutes after the first water has been 

 Bull. U. S. F. C, 84 8 



