the opening. At the end of the process, the abdominal cavity of the fish appears entirely 

 enypty and collapsed but by careful handling the fish suffer no ill effects. 



All eggs can be removed from the female at one stripping, since there are no differ- 

 ences as to maturity or development between the forward and the rear end eggs (according to 

 Ursic). Repeated stripping over a number of days would distress the female unnecessarily. 

 It is not advisable to strip the eggs into sieves so as to drain off the amniotic fluid, 

 since the presence of this fluid increases the motility of the spermatozoids (according to 

 Scheuring), 



It was presumed in former days that stripping of salmonoid species was so relatively 

 easy — as compared with other species — because these fish are minus tubes. Newer investi- 

 gations by Leach and Kendall have shown this to be an error. The mature eggs in trout — 

 according to these authors — are dropped into pseudo peritoneums, into an "ovarian pouch", 

 as it were. This pouch will tear only through rough handling and the eggs will then drop 

 into the abdominal cavity. This will also occur if the head of the female is kept down- 

 ward. The eggs will then fall into the abdominal cavity through a fissure (a cleft) in 

 the rear end of the pouch. This can be harmful to the fish. 



The process of stripping is now repeated with some 2 to A females until the bowl 

 is 1/3 or 1/2 full of eggs. 



Now, a male is caught in the same way as described for the female. In difference 

 to the female, he is held with belly downward and in such a way that the body opening 

 comes over the middle of the bowl. With thumb and index finger the milt is stripped 

 from the fish. The fish practically "slides" through the hand of the operator. (In 

 some case of very large and active fish an assistant may be necessary to hold the fish 

 by the tail.) The amount of ejected — odorless — milt is very small but is sufficient to 

 fertilize a large number of eggs, since it contains large quantities of spennatozoids 

 (in rainbow trout 32 to 39 (1 eq, l/lOOO mm)). Since sterile males are rare among 

 trout, it is sufficient to strip just one specimen. For the safety of greater quantities 

 of eggs, 2 males may be stripped, (Among marSnes and pike, immature males are frequently 

 found. In their case it is best to strip more males than females.) 



Lehmann has pointed out that the use of inferior oil cloth aprons, worn by the 

 operators may cause considerable losses among the parent fishes. A bad oil cloth fabric 

 often contains acids which are injurious to the skin of fish, and it is unavoidable that 

 they come into contact with the apron. 



According to Scheuring. the good quality of the milt of trout is recognized by: 



(1) Good milt is cream-like, while inferior milt is curdly, watery or flaky, 



(2) Good milt has a chloride content of from 0.26 to 0.34- percent and a pH 

 rate of from 7.3 to 7,6, rtiile bad milt or overripe milt shows lower 

 rates. Immature milt can have higher rates, 



(3) Good milt furnishes spermatozoids of long-lasting "motility" and in fish 

 of the same stock of even duration and of great intensity of movement, 



I have to state, though, that so far it is not at all proven that these enumerated 

 qualities are identical with a high virility. Neither is the vivid coloring of a male 

 proof for the good quality of the milt. On the other hand, males (of rainbow trout) 

 whose silvery glow of the belly extends beyond the lateral line, so-called shiny fishes, 

 are almost always sterile and therefore should be eliminated. 



The stripped-off milt is now thoroughly mixed with the eggs by means of the feather 

 (see above), and all foreign matter removed with the tweezers. Only then is water added 

 to the bowl, and eggs and milt are again thoroughly stirred with the feather. After 

 this, the bowl is left alone for about 20 minutes while the operator proceeds again 

 with the stripping of new fish. 



loe 



