FISHES OF THE YELLOWSTONE NATIONAL PARK. 9 



other fish than trout as food for the pelicans, would reduce the 

 output of tapeworm eggs from that source. The fish best suited 

 to that end is the chub (Leuciscus lineatus) and perhaps the silverside 

 minnow (Leuciscus Jiydrophlox) , both of which abound in Heart 

 Lake and Witch Creek. 



Tapeworms would probably disappear from trout transferred to 

 other waters where there are no pelicans, unless by chance some 

 other fish-eating bird may be or might become a host for the adult. 



LIST OF THE FISHES. 



As has been indicated, 10 species of fishes are known to be native 

 to the waters of the park, of which only 3 are reputed to be game 

 fishes. However, 6 others, all game fishes, have been introduced and 

 all but two of them have become acclimatized and afford good fishing. 



A brief discussion of each kind of native and introduced fish fol- 

 lows, preceded by a key intended as an aid to the angler in the identi- 

 fication of his catch. 



The key is arranged on the alternative plan and is to be used in the 

 following manner: Trace the characters of the specimens with what 

 is said under each succeeding letter, until there is a disagreement, or 

 the name of the fish is reached. When a disparity occurs, go to the 

 double of the letter under which it occurs, thence proceed as before 

 until another disagreement or a name is found, and so on. For 

 example, take the brown trout, assuming that it is not recognized; 

 compare it with statement A, with which it agrees; proceed to B, 

 with which it does not agree, having fewer rays In the dorsal fin. 

 Turn to BB, with which it agrees, and by the name in parenthesis it 

 is found to belong to the Salmonidse or salmon family. Then go to &, 

 with which it. is found to disagree in having a large mouth and coarse 

 teeth and more scales than stated. Turn, therefore, to 1)1, where an 

 agreement and the subfamily to which it belongs are found. Pro- 

 ceed regularly then to d, which is also found to agree. Continue to 

 e, with which it does not agree, as it is not profusely blackspotted 

 and has not 130 scales in lengthwise series. Turn to ee, with which 

 it agrees. Proceed to g, with which it does not agree. Then turn 

 to gg, with which it agrees in the number of scales and color descrip- 

 tion^ and the numbered name of the brown trout is reached. The 

 number indicates its place in the annotated list of fishes which follows 

 the key. 



If it is desired to ascertain the name of a specimen of fish without 

 an adipose fin, which, of course, is found not to conform to the state- 

 ment A, turn to AA and proceed as in the foregoing example. 



a The color description of each species as given can not always be relied upon to exactly fit a specimen 

 in hand, owing to the great variability in this respect. However, there will always be more or less approach 

 to the general color scheme as stated, which no other species will show. 



