Table 28. Summary of electrof ishing survey for a 1,000 foot section of 



Twelvemile Creek (T2M, R12W, Sec 4A) on August 6 and August 20, 

 1980. 



Species No. Captured Length Range (inches) 



Brook Trout • 272 2.0 - 9.6 



Rainbow X Cutthroat Hybrid Trout 1 8.8 



[lottled Sculpin - _ 



The standing crop of brook trout in the study section was estimated 

 using a mark-recapture method (Table 29). The section supported approximately 

 314 fish representing a biomass of 27 pounds. Catchable fish (6 inches and 

 longer) composed 35 percent of the population. Brook trout condition (length 

 to weight ratio) was good and slightly below average for Mount Haggin streams 

 and other tributaries of the upper Big Hole River (MDFWP unpublished data). 



Table 29. Estimated standing crop of brook trout in a 1,000 foot section of 

 Twelvemile Creek (T2N, R12W, Sec 4A) on August 6, 1980. Eighty 

 percent confidence intervals are in parentheses. 



Per 1 ,000 ft . 

 Species Size Range (inches) Number Pounds 



Brook Trout 3.0 - 4.9 143 



5.0 - 6.9 112 



7.0 - 9.6 59 



314(+33) 27(+3) 



A 100 foot section of Twelvemile Creek (T3N, R12W, Sec 20) was electro- 

 fished in 1976 (fIDFWP unpublished data). Six brook trout ranging in length 

 from 2.0 to 10.0 inches were collected during the survey. As a result of this 

 inventory, the fishery potential of Twelvemile Creek was noted as fair. 



Twelvemile Creek was found to support a very good brook trout fishery 

 relative to other streams in the Mount Haggin area. Numbers of catchable fish, 

 average weight and brook trout biomass were above average for Mount Haggin 

 streams. Twelvemile Creek supported the second highest number of fish 7.0 

 inches long and greater in the area. 



66 - 



