MISCELLANEOUS FRESH-WATER FISHES. 



Besides the freshwater and anadromous fishes considered in the fore- 

 going chapters, a number of others have been artificially cultivated, 

 including some species introduced from Europe. The special methods 

 of propagation already referred to are in general applicable to all fishes 

 of similar character, and need not be described again in detail. 



MINOR TROUTS AND THE GRAYLING. 



The different methods of hatching the eggs of the various members 

 of the salmon family are practically interchangeable, so that in con- 

 sidering the following species it is not necessary to dwell again on 

 fish-cultural processes. 



Several varieties of the black-spotted trout {Sahno myTciss) are artifi- 

 cially propagated. This fish is somewhat similar to the European sea 

 trout or salmon trout ( Sabno trutta) and in j)arts of its range has the 

 same half-migratory habits. It is widely distributed, very abundant, 

 and subject to great variation in color and structure. It is found from 

 Alaska to Mexico in the streams of the Coast Eange, Sierra Nevada, and 

 Rocky Mountains, and in some lakes in the same regions. It attains a 

 weight of over 30 pounds, although the average is, of course, much less. 



Among the varietieo whose eggs have been artificially hatched are 

 the Lake Tahoe trout or Truckee trout {Sahno mykiss henshaivi), which is 

 extensively propagated by the California Fish Commission at hatcheries 

 on Lake Tahoe; the Colorado River trout {Salmo mykiss pleuriticus), 

 and the yellow-fin trout {Sahno myTciss macdonaldi), both of which are 

 cultivated by the U. S. Fish Commission at its station at Leadville, 

 Colorado. All of these species are handsome game and food fishes. 



In the vicinity of Leadville the spawning season extends from May 1 

 to July 15. The eggs are hatched in the same troughs and under the 

 same conditions as those of the brook and rainbow trouts. In water 

 ranging from 42° to 60° aud averaging about 52° F., the eye-spots 

 appear in 20 days and hatching ensues in 30 to 45 days. 



The Scotch lake trout, or Loch Leven tTont {Salmo trutta levenensis), 

 and the European brown trout or brook trout, or Von Behr trout {Sahno 

 fario), were introduced by the Fish Commission a number of years ago, 

 and have been widely distributed in the United States. They are now 

 propagated in many States from eggs taken from brood fish retained 

 in ponds. At North ville the spawning season of these fish is the same 



179 



