THE RAINBOW TROUT. 



DESCRIPTION OF THE FISH, 



The body of the rainbow trout {Salnio irideus) is comparatively short 



and dee-pj aud is more ehmgate in males than in females. The average 



depth is contained about three and four- fifths times in the body length. 



The short head, which is obtusely ridged above, is about one-fourth the 



total length. The mouth is smaller than in other species of SahnOj the 



maxillary reaching scarcely beyond the eye, which is rather large, and 



is contained five times in the side of the head. The caudal fin is dis 



tinctly but not strongly forked. On the vomer are two irregular series 



of teeth. The dorsal rays number 11 and the anal 10. In the typical 



species there are about 135 scales in the lateral series, with 20 rows 



above and 20 below the lateral line; in the several subspecies the 



number of rows of scales along the side is from 120 to 180, The color is 



variable, depending on sex, age, and character of water. Typical adult 



fish are bluish above, silvery on the sides, profusely and irregularly 



dark-spotted on the back and sides, the spots extending to the vertical 



fins, with a red lateral band and blotches and a nearly plain belly. The 



sea-run fish are nearly jjlain silvery. The chief distinguishing color 



characteristics of the varieties are in the number and position of the 



spots. 



ranctE and variation. 



The rainbow trout is not indigenous to eastern waters, its original 

 habitat being the Pacific coast of the United Stales. It is especially 

 abundant in the mountain streams of California. A few specimens, 

 however, have been taken in salt water, and it is not unlikely that some 

 find their way through the rivers into the sea. 



The species is subject to considerable variation in form and color in 

 different parts of its range, and the following varieties have received 

 recognition by ichthyologists: The brook trout of western Oregon aud 

 Washington {Salnio irideus masoni), which rarely weighs as much as a 

 pound and is locally abundant in the streams of the Coast Eangefrom 

 Puget Sound to southern Oregon; the McCloud River trout [Salmo 

 irideus shasta), which attains a large size, is abundant in the streams of 

 the Sierra Xevada Mountains from Mount Shasta southward, and is the 

 rainbow trout which has received most attention from fish culturists; 

 the Kern River trout {SaJvio irideus gilberti), which attains a weight of 

 8 pounds, and is found only in Kern Kiver, California; the noshee or 

 nissuee trout {Salmo irideus stonei), which inhabits the Sacramento 

 basin, and reaches a weight of 12 pounds; the golden trout of Mount 

 Whitney (Salmo irideus aqua-honifa)^ which inhabits streams on both 

 sides of Mount Whitney, California. 



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