Yellowstone Lake in Yellowstone National Park, Wyoo^, has for many 

 years been known for its production of black-spotted or cutthroat 

 trout ( Salmo clarkii lewisi), the only species of game fish presento 

 Few lakes in the United States offer recreational fishing equal to 

 that of Yellowstone lakee With over 100 miles of shoreline and 135 

 square miles of siirface, the lake affords good fly and bait fishing 

 and trolling from private and rented boats <> The success of anglers 

 fishing Yellowstone Lake in past years has caused an ever-increasing 

 number to visit its waters. Concurrent with the normal increase at- 

 tributed to successful fishing, there has been since World War II a 

 Nation-wide increase in travel c During each of the summer seasons of 

 19hO and 19lil^ approximately ^00,000 persons visited Yellowstone Park* 

 In the war years from 19U2 to 19h^} there was an expected decrease in 

 visitors which reached a low 100,000 in 19U3 and 19UUo Since the end 

 of the war there has been an ever-increasing nuiaber of visitors; since 

 19ii8, the annual number has never been less than a milliono 



In conjunction with the increase in total visitors, there has been 

 a noticeable increase in the number of anglers » The effects on the 

 Yellowstone Lake fish population of this increased fishing effort has 

 become a problem of utmost concerno 



Because of the problem of increased fishing pressure on Yellowstone 

 Lake, the Fish and Wildlife Service, at the request of the National Park 

 Service, initiated an extensive study to learn the effects of the in- 

 crease, and to make recommendations, based on their findings, for a plan 

 for a sustained yield fishery. This report is concerned with the results 

 of the first two years of creel census studies. The study was initiated 

 in 1950 and expanded in 19^1 for collecting data for the determination of 

 total armual fishing mortality. Data were collected in such a manner 

 that fishing effort and success could be analysed for relative annual and 

 intro-seasonal changes, and for differences between major fishing areas 

 of the lakeo 



The expansion of the 1951 program entailed the development of a 

 practical method of censusing the Yellowstone Lake shoreline and the 

 Yellowstone River, This problem was solved by the mathematical deri- 

 vation of a census method included in this report as an appendixe 



We are grateful to the National Park Service and the Yellowstone 

 Park Company officials and employees, for their enthusiastic cooperation 

 and interest in this study. To W. A. Dunn, Superintendent, U. S. Fish- 

 eries Station, Yellowstone Park, we are deeply indebted for his cooper- 

 ation in furnishing quarters and facilities for this project. Professor 

 A. H. Bowker of the Statistics Department, Stanford University;-, made sug- 

 gestions fcr the development of several features of the statistical presen- 

 tation o 



