FWP biologist predicts ‘not very good’ trout counts on Big Hole River

Butte, Montana – The Big Hole River is a fly fishing haven, much like Maiden Rock near Butte, but trout populations in this stream have been declining at an alarming rate in recent years, which has fish researchers and fishermen very worried.

“I’m quite worried. This is due to A the limited overall population and B the scarcity of tiny fish. Therefore, the outlook for the upcoming year and the years is not very promising, according to FWP Fish Biologist Jim Olsen.

Recent fish counts reveal there are somewhat fewer than 500 trout per mile in the river between Jerry Creek Bridge and Browns Bridge. There are typically 350 to 400 rainbow trout and between 900 and 1,100 brown trout in the river.

Taking population estimates along the river since the late 1960s, we are currently at our lowest point ever, according to Olsen.

Anglers and outfitters are concerned about the declining fish population.

Owner of Great Divide Outfitters Lia Jones in Divide said, “It’d be honestly an economic collapse if this fishery went down and it wouldn’t just be the Big Hole—it’d be the entire Jefferson River Basin.”

Biologists are concerned that one of the causes of the reduction may be a fish-affecting sickness.

“It’s very difficult to develop a management strategy to hopefully stop that and reverse that trend because we don’t understand exactly what’s causing what’s going on,” said Olsen.

Outfitters in the area have requested inquiry on this topic in a letter to the governor and state assembly.

“Science is required to understand this stuff. Fish that are currently in labs need to have the cause of their deaths investigated; if this is done, the process of correcting the issue might proceed more quickly, said Jones.

Anglers should call Olsen at (406) 533-8451 if they capture fish that exhibit disease-related symptoms, he advised.