It is necessary to introduce a probabilistic adjustment to each 

 count, since the observer is unable to view an entire strip from a 

 single vantage point and make an exact counto The resulting number 

 is then adjusted, through the frequency histogram, to give an estimate 

 of the total nximber of hours of effort that would take place within 

 that strip in the entire fishing day. 



Four driving trips along the entire lakeshore are made during 

 each biweekly period^ and their results are pooled in such a manner 

 as to give an average estimate of the total number of hours of effort 

 for the lakeshore during this periods 



The total number of hours of effort is regarded as being the 

 fundamental quantity under considerationo M-ultiplying it by suitable 

 ratios^ estimates are made for the total number of individual fishermen 

 and the total catch for the biweekly period,, 



NQTE m YELLeWSmNE RIVM 



The sampling procedure for Yellowstone Lake lends itself well to 

 studying the fishing situation on Yellowstone Hivero There isj how=> 

 every one important change. The behavior pattern or river fishermen 

 is to fish in a number of locations, spending ar certain amount of time 

 at eacho The calculation for No, the estimated number of individual 

 fishermen on the river during the biweekly period, must be adjusted to 

 compensate for this tendency. Unaltered, it estimates the total number 

 of fishing stops within the periods It must therefore be divided by the 

 average number of stops made by each fisherman, in order to represent 

 the number of individual fishermen patronizing the fishery. An interview 

 scheme can yield the average niomber of stops per angler. 



If we call this average number of stops per fisherman Xj then in 

 terms of the symbology of the subsequent mathematical treatment^ 



Nf.( adjusted for river) « H__ 



IK 



Nf 



where Nr. is given by a straightforward formula. 



33 



