72 KEPORT OP COMMISSIONER OF FISH AND FISHERIES. 



In tlie extensive section of the West in which the fish abounds its 

 name varies in diflt'erent localities; "red sides," "mountain trout," 

 "brook trout," and "golden trout," besides "rainbow trout," are some 

 of the popular appellations, while in the States east of the Mississippi 

 Kiver it is generally called "rainbow trout" or "California trout." 



TRANSPLANTING. 



The rainbow trout has been successfully transplanted in many of the 

 mountain streams in different parts of the United States, where it 

 grows and multiplies rapidly, as is shown by the many favorable 

 reports. The best results, however, seem to have been obtained from 

 plants made in streams of Michigan, Missouri, Arkansas, throughout 

 the Alleghany Mountain ranges, and in Colorado, Nevada, and other 

 Western States. It was introduced into eastern waters by the United 

 States Fish Commission in 1880, but it is possible that specimens of it, 

 or its spawn, had been brought east prior to that time by some of the 

 State commissions or by j)rivate enterprise. 



It is believed that this species will serve for stocking streams for- 

 merly inhabited by the brook trout {Salvelimis fontinalis), in which the 

 latter no longer thrives, owing to the clearing of the lands at the 

 sources of the streams, which has produced changed conditions in and 

 along the waters not agreeable to the brook trout's wild nature. The 

 rainbow is adapted to warmer and deeper waters, and is therefore 

 suited to many of the now depleted streams which flow from the moun- 

 tains through the cultivated lands of the valleys. 



Eainbow trout differ widely from brook trout and other pugnacious 

 fishes, in that they feed principally upon worms, larvse, Crustacea, and 

 the like, and do not take readily to minnows as food. They should be 

 planted in spring or early summer, when their natural food is abun- 

 dant, as they will then grow more rapidly and become accustomed to 

 life in the stream; and when wocms, larvse, etc., are no longer to be 

 found, their experience and size will enable them to take a minnow or 

 anything that may present itself in the shape of food. 



In the Eastern States fry should not be planted in open waters until 

 tliey are several months old, and then not until the temperature of the 

 streams begins to rise; but fish hatched in December and January can 

 safely be planted in April and May. On the Pacific slope the fry may 

 be successfully liberated at any time after the umbilical sac is absorbed. 



SIZE AND GROWTH. 



The size of the rainbow trout depends upon its surroundings, the 

 volume and temperature of the water, and the amount of food it con- 

 tains.. The average weight of those caught from streams in the East is 

 probably less than a pound, but some weighing tJ^ pounds have been 

 taken. In the Ozark region of Missouri they are caught weighing 5 to 

 10 pounds. In some of the cold mountain streams of Colorado their 

 average weight is not more than (3 or 8 ounces, but in lakes in the 



