d ) Ag e Structure 



Trout population age structure was determined through the examination 



of scale samples collected from fish by 1/2 inch intervals. Estimates of 



the numbers of brook trout within different age groups are presented in 

 Table 8. 



Table 8. Estimated numbers* and percentages* (in parentheses) of brook trout 

 within different age groups of populations surveyed in 1,000 ft 

 study sections on Mount Haggin streams. 



Age Group 



Stream I II III IV+ 



Seymour Creek - 228(44) 128(25) 145(28) 19(4) 



Sullivan Creek - 304(50) 161(27) 124(21) 14(2) 



Twelvemile Creek 



Slaughterhouse Creek 



Tenmile Creek 



Sevenmile Creek 



Deep Creek 



Sixmile Creek 259(56) 



Oregon Creek 



American Creek 



California Creek 



Wi 1 low Creek 



*Rounded to the nearest whole number. 



As would be expected in most populations, the greatest numbers of fish were 

 found in the lower age groups (I and II) for most Mount Haggin streams. The 

 only estimate of age fish was made on Sixmile Creek where they comprised 

 66 percent of the populations. Age III and IV or older fish represented 25 

 percent or less of the brook trout population in all of the study sections 

 except Seymour, California and Deep Creeks. Because of the low population 

 numbers of rainbow trout in the studied streams, no estimates by age group 

 will be treated in this report. The age structure of the Willow Creek cut- 

 throat trout population was determined to be, 2 age I fish, 17 age II fish, 

 38 age III fish, and 6 age IV and older fish representing 3,27, 60, and 10 

 percent of the population, respectively. 



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