22 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



screeu. The yolk of boiled eggs is also suitable, but it is comparatively 

 expensive and is not so good for the fish as liver unless largely mixed 

 "with it. 



As the fish grow older they continue to thrive best on meat food, but 

 if that is not always obtainable in sufficient quantities or on account 

 of its exi^ense, a very good substitute is a mixture of shorts or corn 

 meal with the meat. This is prepared as a mush by stirring shorts or 

 middlings into boiling water, a little at a time, so that it will not cook 

 in lumps, but become more of a paste. After it has thoroughly cooked 

 it is allowed to cool and harden. The best proportion is 30 pounds of 

 shorts to 25 gallons of water with 3 or 4 pounds of salt. The per- 

 centage of liver to be used in this mixture should be regulated by the 

 age of the fish, feeding the very young fry upon almost a simple meat 

 diet and increasing the proportion of mash with the age of the fish. 



Doubtless for young Salmonid/v the best natural fish food, not arti- 

 ficially bred, is the roe of fishes which have minute ova, as the best 

 food for the mature fish is live minnows. These foods furnish the fish 

 with a clean, suitable diet and leave no decaying matter on the bottom 

 of the troughs or ponds to foul them or produce disease. But these 

 foods can rarely be obtained without too much expense, although the 

 time will undoubtedly come when perch, carp, and similar coarse fish 

 will be economically propagated and raised to serve as food for trout 

 and salmon. Herring roe is now canned for fish food, and if this can 

 be furnished at a sufficiently low price ic may ultimately provide an 

 excellent food for young salmon. 



PLANTma THE FRY. 



The most promiiient instinct of the newly-hatched salmon is to burrow 

 for concealment, and this habit persists until the necessity for active 

 feeding compels them to come from their hiding-places. The retention 

 of salmon in troughs for a number of months after they begin to feed 

 naturally leads to a considerable change in their instincts and makes 

 them less liable to escape from their enemies after being planted. The 

 fry are liberated on the natural spawning-grounds, as a rule, as soon 

 as the umbilical sac is exhausted and they show a disposition to feed 

 at the surface. When, for any reason, the fry are held longer, their 

 growth varies in accordance with the character and temperature of the 

 water in which they are reared and the food they receive. The young 

 fry reared at Baird station grow to a length of 2^ inches from the time 

 when they begin to feed in February until the middle of May, when, 

 on account of the rising temperature of the water, they are liberated in 

 the McCloud Eiver. 



