DISCTJSSION AND CONCLITSIONS 



Roosevelt Lake is surrounded by attractive country which is well 

 suited for recreational and sightseeing purposes because of its moun- 

 tainous terrain, virgin park like forests, and scenic drives; it has 

 not yet, however, been utilized extensively. Since the lake had pro- 

 duced rather poor fishing the National Park Seirvice was of the opinion 

 that improved sport fishing might be influential in attracting more 

 people to take advantage of recreational facilities of the lake. The 

 Park Service, therefore, was instrumental in inaugurating the surveys 

 made by the Fish and Wildlife Service in 1948, 



The results of the investigation were in general found to be 

 favorable : 



1. pH's, carbonates, bicarbonates, carbon dioxide, oxygen 

 were present in proportions favorable to bacterial growth, photo- 

 aynthetio activities of chlorophyll bearing plants, and fauna. 



2. Low free carbon dioxide content, complete absence of 

 hydroxides, and good dissolved oxygen content were indicative of 

 freedom from pollution. 



3. Plankton hauls were fair to good in the downstream portion 

 of the reservoir, ccmparing favorably to fish producing bodies of 

 water such as Karluk Lake, Alaska; Tieton Reservoir, Washington; 

 and Arrowrook Reseinroir, Idaho. 



4. From the fish sampling work, Roosevelt Lake appears to 

 compare favorably with Cultus Lake, B. C, in production of rough 

 fish. 



There were, however, same unfavorable factors t 



1. Absence of a cold water layer may prove incompatible to 

 the well being of certain fishes. 



2. The extreme turbidity existing in July is not regarded as 

 favorable to production of phytoplankton (this may have been an 

 abnormal condition as a result of the unprecedented floods of 1948), 



3. Meager plankton hauls in the upper reservoir were not in- 

 dicative of good productivity in that portion of the lake (this 

 condition also may have been aggravated by the spring flood in 1948). 



4. No salmonoids were caught in the experimental fishing with 

 gill nets, indicating scarcity of these game fishes. 



5. Fish sampling indicated that large populations of xm- 

 desirable rough fish exist, such as squawfish, chubs, suckers, and 

 carp. 



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