18 U. S. BUREAU OF FISHERIES. 
In the park it naturally occurs in the Yellowstone River below 
the falls as far up as Crevice Gulch, beyond which it is seldom found, 
in Madison and Gallatin Rivers below the falls, and has been reported 
also from the junction of Firehole and Gibbon Rivers. At the 
junction of Lewis and Snake Rivers “grayling,”’ or “mountain 
herring,” are reported as taken by anglers; these are doubtless 
whitefish. 
Young whitefish 2 to 5 inches long from Montana were planted in 
park waters, as follows: In 1889, 2,000 were placed in Twin Lakes 
and 980 in Yellowstone River above the falls, and 10,000 more were 
planted in the latter place in 1890. It is considered doubtful if any 
of these have survived, owing to the number and size of voracious 
trout in the Yellowstone River and the mineral character and high 
temperature of Twin Lakes. 
This fish prefers clear, cold lakes and streams, where the usual 
length of adults is about a foot, although it is known to have attained 
a weight of 4 pounds. The cismontanus form is essentially a river 
fish rather than an inhabitant of lakes and is most abundant in the 
Be % Es 
ou g 
Fic. 2.—Rocky Mountain whitefish. 
eddies or deeper places of swift streams. It spawns in late fall or 
early winter. Thisis a slender, graceful fish, readily taking the arti- 
ficial fly hke a grayling or trout, as well as natural baits, such as 
worms and insects and even fresh meat. However, owing to the 
smallness of its mouth, the hook should be no larger than No. 10 or 
12, and when hooked the fish requires careful “playing” owing to 
the tenderness of the mouth parts. It is a game fighter. It ranks 
high as a panfish, for, when in condition, it is of surpassing sweetness 
and delicacy of flavor. 
3. ReptHrRoAatT Trout: CutrrHroat Trout: BLAacksPpoTtTED TROUT 
(Salmo lewist). 
(See frontispiece.) 
In its numerous varietal, subspecific, or specific forms the red- 
throat, cutthroat, or blackspotted trout is of extensive distribution 
on the Pacific slope. In the park a form designated as Salmo lewisi 
is found naturally in both upper Snake and upper Missouri waters, 
having doubtless gained access to the latter from the Snake River 
by the way of Two Ocean Pass, and it is not unlikely that an inter- 
change of individuals still takes place. 
