This Will Make Fly Fishers Smile on Valentine’s Day: Missouri River Trout Numbers

by Mark McGlothlin on February 14, 2013

in River - Missouri

MoMap14Feb13Respectfully recognizing that not everyone buys into the hype and hoopla of Valentine’s Day, here’s some fishy data that is bound to bring a smile to the most curmudgeonly fly angler who’s fishing Montana this year.

Via Bruce Auchly, FWP via the Billings Gazette a couple of days ago -

Fish surveys last year show rainbow trout numbers were more than double the long-term average in the Missouri River between Holter Dam and the town of Cascade.

State fisheries crews last fall estimated 7,312 rainbow trout greater than 10 inches long per mile near the town of Craig on the Missouri. The long-term average for that section is 3,036.

Fish, Wildlife and Parks fisheries biologist Grant Grisak attributed the larger number of fish to the high water years of 2010 and 2011. Both years had flows in the springtime of more than 18,000 cubic feet per second downstream of Holter Dam.

“We found when flows are over 18,000 cfs, we generally have record numbers of rainbow trout,” Grisak said. “A similar situation occurred in 1996, ’97 and ’98.”

Besides more water in the Missouri River main stem, the increased flow “flushes fish out of the tributaries,” Grisak said. “That increases survival with more space, more food and less chance of whirling disease infecting young rainbows.”

Brown trout numbers near Craig were also up. Brown trout longer than 10 inches were estimated at 850 per mile. That compares with the long-term average of 570 per mile…

Tags: River - Missouri