dorsal fin erosion. A rainbow trout was considered to be of hatchery origin if its dorsal 

 fin showed a Irayed or malformed appearance, especially on the distal ends of the first 

 few fin rays. Each fish was identified with a unique number which was recorded on the 

 data sheet, scales sample envelope, and a vertebrae sampling envelope for rainbow trout. 



Analysis 



Each data set was keypunched into Microsoft Excel spreadsheets. Count and interview 

 data were used to calculate fishing pressure (angler-hours and angler days), catch rates, 

 and harvest according to equations detailed in Neuhold and Leu (1957) and analyzed in 

 Montana Fish Wildlife and Parks Creel Census Program (McFarland and Roche 1987). 



Fishing pressure, catch rates, and harvest were calculated for each stratum by section 

 (North or South halO and pooled by calendar month for fiirther analysis. Other data sets 

 were analyzed using Excel or Statistix 7.0 (Analytical Software 2000). 



During the summer creel strata (June 1 2 to September 30), a miscommunication resulted 

 in clerks only recording interviews with successful anglers. Because of the obvious bias 

 created by omitting unsuccessfial anglers, four data sets were developed: 



1 . Base: Included all actual interviews with successfiil anglers fi-om June 1 2 - 

 September 30, 2000 and all (successful and non-successful anglers) interviews 

 thereafter 



2. Edits: hicluded only completed interviews with successful anglers fi-om June 12 - 

 September 30, 2000 and all actual (successful and non-successful anglers) 

 interviews thereafter 



3. Editshigh: hicluded completed interviews with successful anglers fi-om June 12 - 

 September 30, 2000 and projected non-successfial angler interviews based on 

 recorded party sizes with clear references to other anglers, and all actual 

 (successful and non-successfijl anglers) interviews thereafter and 



4. Highbase: hicluded all interviews with successfiil anglers fi-om June 12 - 

 September 30, 2000, all projected non-successful angler interviews based on 

 recorded party sizes, and all actual (successful and non-successfiil anglers) 

 interviews thereafter. 



To ensure that bias was minimized, each dataset was analyzed separately. Pressure 

 estimates (angler hours) were independent of datasets (Chi-square =0.89, p=0.64). Catch 

 rates and harvest each varied between data sets due to different interview outcomes. 

 These results were compared using Chi-Square Association tests, ANOVA, and t-tests to 

 determine whether results varied significantly and to choose the least biased estimate for 

 further analysis and reporting. 



Analysis of Rainbow Trout Origin 



Creel clerks collected scales fi-om each fish sampled. Up to three scales were mounted on 

 acetate film and pressed in a heated hydraulic press to create impressions. Age of fish 

 was determined by viewing acetate plates under a Microfiche projector as described by 



