NORTHWESTERN LAKES OF THE UNITED STATES. 
75 
was only one-third full, and the material was so nearly digested that fully 90 per 
cent of it was unrecognizable. The remainder of the material consisted of about 
equal portions of fishbones, fish eggs, amphipods, beetles (Coleoptera) , and may- 
flies (Ephemerida) . 
UPPER KLAMATH LAKE, OREG. 
This lake is but 10 m. deep, and plant and animal life thrive in it abundantly. 
The lake is well stocked with unusually large rainbow trout ( Salmo irideus), but 
the temperature of the lake was almost too warm to find a good quality for food. 
Several fish were caught and the contents of the stomach preserved. Nothing was 
found in these stomachs except small amounts of the remains of other fish. 
CRATER LAKE, OREG. 
Rainbow trout ( Salmo irideus ) seemed to be fairly abundant, and several 
stomachs were secured in order to ascertain on what they were feeding. The 
stomachs were fairly well filled. The following table shows the proportion of 
different kinds of food found in the stomachs : 
Table 3. — Food from stomachs of six rainbow trout, Crater Lake, Oreg., August 3, 1912. 
Number of trout. 
Corethra 
larvae. 
Daphnia. 
Mollusca. 
Debris. 
Per cent. 
Per cent. 
Per cent. 
90 
Per cent. 
10 
75 
20 
5 
2 
20 
80 
Three stomachs were full of univalve Mollusca and two were well filled with 
large Daphnia pulex. Near the shore of Wizard Island, where the fishing seemed to 
be best, a great many swarms of Daphnias could be seen along the shore. The 
abundance of food in this vicinity may account for the large number of trout in 
this area. The Daphnias were of unusually large size. 
GREEN LAKE, WASH. 
Several crappies ( Pomoxis annularis) were secured from this lake. Daphnias 
seemed to form the predominant part of the fish food, although in many cases 
Corethra larvae were found in large numbers in the stomachs, as is shown in the 
following table: 
Table 4. — Food from stomachs of Jive crappie, Green Lake, Wash., August 9, 1913. 
Number of crappie. 
Corethra 
larvae. 
Crus- 
tacea. 
Plants. 
Debris. 
Per cent. 
90 
Per cent. 
2 
Per cent. 
Per cent. 
1 
5 1 
15 
20 
-\ 
50 
50 
1 
90 
2 
1 
30 
60 
10 
Green Lake is rather shallow and full of weeds and algae, which accounts for 
this portion of the food in some of the stomachs. The stomachs of these fish were 
all well filled. 
