Average catch-per-unit-effort values for each unit of the fishery 

 for the two seasons are also shown in table 19o Although not signif- 

 icantly different, the rates for the rental boat fishing activities 

 tend to be slightly higher in 195lc As the catch-per-uniife^effort is 

 considered a reliable index of relative fishing successc, it can be con= 

 eluded that on the average^ fishing was better in 19^1* although the 

 difference is not great enough to be statistically significanto 



The results of the two years of extensive creel census on 

 Yellowstone Lake indicate that increasing fishing pressure is not at 

 the present time causing a reduction in the fish popu3.ationo Con- 

 tinuous increases in fishing pressure as have been demonstrated in the 

 years following World War II will show their effect on the fishery in 

 timeo There is^, however j, a maximum fishing pressure which can be maiR= 

 tained without serious detrimental effects to the fisheryo There is 

 nothing evident from the 1950 and 1951 creel census results to indicate 

 that this point has been reached. Biological studies on size and 

 growth of the Yellowstone Lake trout are being carried on in conjunction 

 with the creel census programo Results of these studies will provide 

 evidence of any change in average size or condition of the fish in the 

 catch or spawning runSo A reduction in average size also may be an in= 

 dication of over fishingc The entire Yellowstone project is designed 

 in such a manner that indications of failure of the fishery can be 

 readily recognized, and practices can be recommended which will provide 

 a sustained yield population of trout for superior recreational fishing. 



30 



