142 RKPOKT OF COMMISSIONER OF FISH AND FISHERIES. 



irrigatiiij; ditches luid arc left to ])cri,sli in (lie fields. 'I'lie destnielioii of trout by 

 this agency is far greater than that dno to all others coinbined, and it is going on iu 

 almost every irrigating ditcli in Colorado. 



The fishes of ( /olorado coinpiise very few species, only 32 indigenous 

 species being enumerated by Dr. Jordan, of which 2 were new to science. 



Tlie Rocky Mountain trout, Snlmo mylciss^ is found in all the inoun- 

 fain lakes and streams tributary to the four main rivers, extending 

 down to a x>oint where the summer temi)erature reaches 60° to 65° F., 

 where it gradually disappears. The mountain minnows, Rhinichthys 

 duh-i.s on the eastern slope and Afjosia yarrowi in the Colorado basin, 

 accompany the trout in the mountain meadows, not, however, ascending 

 so near to the sources of the streams, but, on the other hand, much 

 farther down their courses. They are eaten by the trout. Tlie blob 

 or miller's thumb is very abundant in the clear and cold waters of the 

 Colorado basin, and is very destructive to the eggs of trout. The 

 suckers extend up the rivers more or less to the point where the trout 

 disappear, and, for the most part, the species are different in the differ- 

 ent basins. The species of Catostomus and Xyrauchen reach a consid- 

 erable size, but are of poor quality for food. The suckers and the 

 chubs, especially the latter, are very destructive to the trout eggs. 

 The Ftychochcihis hicius of the Colorado attains a great size, and iu 

 default of better fish assumes economic importance. The bulk of the 

 rich launa of the Mississippi, as well as most of the Texan fishes, are 

 excluded from Colorado on account of the intervening turbid waters 

 through which they can not ascend. 



Three species of the Salmonidw have been introduced into some of the 

 streams and lakes of Colorado, the Eastern brook trout most exten- 

 sively, the rainbow trout of California, and the landlocked salmon of 

 Maine. Carp x)onds have also been established in tlie State, and Dr. 

 Jordan strongly recommends the introduction of the larger catfishes 

 •into the tributaries of the lower Colorado, the entire basin of that river 

 having, besides the trout, only fishes of very inferior quality for food. 



Ti'ibutary to the Arkansas River are the Evergreen Lakes, a series 

 of trout ponds, wholly or partly artificial, fed by cold streams from the 

 flanks of Mount Massive. One of these streams, having its rise in the 

 largest permanent snow field in Colorado, has been chosen as the site 

 of the new U. S. Fish Commission hatchery. Dr. Jordan states that no 

 better lo(;ation for that purjiose could be desired. 



In Utah no permanent streams of any imiiortance, except tlie Colo- 

 rado River, occur to the east of the Wahsatch .Mountains. West of the 

 divide of those mountains lies the Great Basin, in which the Salt J^ake 

 Basin and the Sevier River were examined. In the former 14 species 

 of iish, including the front, >SVf/wo myJihs, were taken, and in the latter 

 7 species. The trout of Utah Lake ar(> of excellent quality and reach 

 a weight of 3 to 10 poiiinis. The same trout also occurs iu Ranquitch 



