Fisheries Health

In Montana, fishing for trout is older than the State itself.

Montana offers superb fly fishing for trout in dozens of beautiful rivers and countless alpine lakes. The scenery is stunning, and while some waters are quite popular, fishing pressure on most of the rivers and lakes in Montana can be surprisingly low.

Did you know it takes more than cold, clear water to make a superb trout fishery: it takes excellent water chemistry.  Many waterways in Southwest and West-Central Montana benefit from ancient limestone deposits.  Limestone erodes into waterways and, in the process, creates chalk-bottom rivers ideal for fishing.  Chalk, like other alkalkine minerals, has a strong alkaline pH that encourages plant growth.

Healthy aquatic plant growth supports robust macroinvertebrate and crustacean populations, and boy don’t we know trout love their hatches!  Depending on flows, rivers in Montana can look much like natural spring creeks, a seasonal variation that pays dividends for fishery health.  Further, many Montana rivers possess almost ideal spawning habitat.  Whether it is a side channel or the main stem itself, the critical pea-sized gravel is plentiful. Rainbows spawn in April, May and June, while browns do their thing in November and December.

Montana is also unique in that the vast majority of its trout fisheries are wild! In fact, cold water fish are such an important consideration in Montana that state water quality laws base assessments of waterway health, in part, on whether waterways meet criteria for a “Cold Water Fishery.”

Southwest and West-Central Montana are also home to rare fish species.  For example, the Big Hole Valley contains the last self-sustaining wild population in the lower-48 of fluvial Arctic grayling, a Montana Species of Special Concern and a federal candidate species.  Montana Species of Concern are native animals breeding in the state that are considered to be “at risk” due to declining population trends, threats to their habitats, or restricted distribution.


Upper Missouri Waterkeeper works to protect the health and viability of Southwest and West-Central Montana’s fisheries.  We monitor federal, state, and local decisionmaking concerning land and water uses to ensure that science and fishery health is considered in each decision. We also work to enhance the good, local fishery and habitat restoration work that many local watershed groups perform by ensuring science – not politics or money – guides decisionmaking affecting water resources.