EXPERIMENTS IN FISH CULTURE 

 By Philip G. Zalsman. 



Trout culture has been so much discussed that very 

 little that is new remains to be said. I wish, however, 

 to give the results of some experiments in crossing 

 Brook, German Brown, Silver or Lake Tahoe, Rainbow 

 and Lake Trout.* It is commonly supposed to be quite 

 difficult to cross some species of trout, especially the 

 rainbow and brook, but with the latter cross my experi- 

 ments have been successful. 



I have crossed brown trout eggs with brook trout milt 

 and vice versa. These eggs did very well and some of 

 them hatched out nicely, but I doubt if either cross will 

 produce eggs or milt. Silver trout eggs were also crossed 

 with brook trout milt, the resulting females producing 

 eggs. In this cross the back of the fish resembles the 

 brook trout, but the lower part of the body is similar 

 to the silver trout. 



Crossing rainbow trout eggs with brook trout milt 

 also gave successful results, though I am not aware that 

 this has been done before. In correspondence with the 

 Commissioner of Fisheries I was informed that in their 

 attempts to produce this cross at various stations "the 

 results have been of a negative character." I also 

 crossed the brook trout eggs with rainbow trout milt, 

 but was not so successful, though I did raise some to the 

 feeding stage. I was obliged to take the eggs in Febru- 

 ary from some stragglers, which of course were not so 

 good as those taken in the earlier part of the season. 



The following table gives some results of experiments 

 in fertilizing brook trout eggs under various conditions : 



Experiment 1 : Condition of eggs. Condition of milt. Resulting hatch. 

 Fresh. Fresh. Good. 



After 15 min. After 15 min. 15% 



After 1 hr. After 1 hr. 



*These experiments were carried on while in the employ of the Michi- 

 gan and Wisconsin State Fish Commissions. 



