Here are some details that I find telling, from the Montana FWP EIS:
--33 miles of stream involved
--Yellowstone cutthroat genetics are 99.5% pure (.1% rainbow trout, .4% westslope cutthroat) and there is a fish barrier in place downstream to prevent further rainbow introgression.
--Brook trout are already under must-kill regs. I've seen a grand total of two (and they swam towards the light).
--Last year, MT FWP and YNP combined to shock and remove only 102 brook trout (from the entire 33 miles of stream), including only 7 young of the year. The peak year for brook trout removal was 2005, with only 1104 removed. A grand total of 2,608 brook trout have been removed. They have not been able to find more than 200 per year since 2006.
Owner, Yellowstone Country Fly Fishing
Head Guide, Parks' Fly Shop
Fly Designer, Montana Fly Company
Author, Yellowstone Country Flies and River Characters