Brown Trout Regulations Public Scoping

The department is seeking public input on fishing regulation changes to address declines in brown trout. Input will be used by the department to develop regulation proposals for the commission to consider at its August meeting.

Due to growing public concern regarding brown trout declines in some popular SW Montana fisheries, the department is considering fishing regulation changes for select waterbodies. The department has seen continued declines in brown trout abundance in several rivers. Although each river has unique population drivers, there are some common trends.

Over the past year, the department has been working with the U.S. Geological Survey to compile long-term fisheries data from 41 fisheries monitoring sections in 14 rivers. Results will help evaluate fisheries trends with large-scale variables that may be influencing brown trout populations. Although full analysis is not complete, preliminary results suggest that flow is a primary limiting factor for many brown trout populations. The department continues to analyze these data and explore other potential causes of brown trout population declines.

Since all the evaluated fisheries are managed as wild trout fisheries (no fish are stocked), the department has a limited set of tools to manage these populations. The department will continue to work with water users and agriculture producers to improve flows during critical times and improve habitat where possible, but these efforts take time. As such, anglers on several rivers are requesting the department implement regulation changes to act in the short-term.

Short-term trends have shown reduced numbers of small, juvenile brown trout in the Big Hole River, Ruby River, Boulder River (tributary to the Jefferson), Beaverhead River, upper Yellowstone River, Madison River, and upper Stillwater River (tributary to the Yellowstone). Currently, these are the primary waterbodies where the department is considering regulation changes. Depending on public input, the department may implement regulation changes to entire rivers or may change sections of rivers to evaluate effectiveness of regulation changes.

Listed below are potential fishing regulation changes that the department is considering. On their own, none of these proposed changes are expected to drastically improve brown trout population abundance; however, each may reduce some stressors to the population during critical periods.

Adopt seasonal fishing closure to protect spawning brown trout

On some or all of the following rivers or sections of rivers and/or tributaries:

• Big Hole River
• Ruby River
• Upper Yellowstone River
• Boulder River (tributary to the Jefferson), and/or
• Beaverhead River.

This would adopt a seasonal fishing closure for all species from September 30 until the third Saturday in May to protect brown trout redds and reduce stress from angling. This closure would limit fishing opportunity during the late-fall and early-spring, which have seen increased fishing pressure in recent years. Overall effectiveness of this regulation is limited since few anglers harvest brown trout; however, it could reduce stress from catch-and-release angling during the spawning period. A fishing closure could also reduce incidence of trampling eggs deposited on redds. This seasonal fishing closure would encompass the period from brown trout spawning until fry emergence in spring. Additional drought restrictions (i.e., “hoot owl” restrictions) and fishing closures can be implemented when critical temperature or flow criteria areMaintain regulations currently in place. Since environmental conditions, such as flow and temperature, appear to limit brown trout populations more than angling, maintaining regulations already in place may be adequate to sustain wild populations until improvements to flow and habitat are achieved. Angling opportunity and angler displacement would be expected to remain at current levels. Additional drought restrictions (i.e., “hoot owl” restrictions) and fishing closures will still be implemented when critical temperature or flow criteria are met, typically during the late summer months. This regulation would be expected to displace anglers to other waterbodies because fishing would be limited to the third Saturday in May through October 15.

Catch and release fishing only for brown trout

On some or all of the following rivers or sections of rivers and/or tributaries:

• Big Hole River
• Ruby River
• Boulder River (tributary to the Jefferson)
• Beaverhead River
• Upper Yellowstone River
• Madison River, and/or
• Upper Stillwater River (tributary to the Yellowstone)

No harvest for brown trout would be allowed year-round. Effectiveness of this regulation is limited as few anglers currently harvest brown trout. Delayed fishing mortality could affect populations during high stress periods, such as low flows and high temperature periods or during fall spawning. This option limits angling opportunity throughout the year. Additional drought restrictions (i.e., “hoot owl” restrictions) and fishing closures can be implemented when critical temperature or flow criteria are met, typically during the late summer months. This regulation could displace some anglers to other waterbodies.

Implement standing hoot-owl restrictions from July 1 – August 15

On some or all of the following rivers or sections of rivers and/or tributaries:

• Big Hole River
• Ruby River
• Boulder River (tributary to the Jefferson)
• Upper Yellowstone River, Madison River, and/or
• Upper Stillwater River (tributary to the Yellowstone)

This regulation would limit fishing pressure to the coolest part of the day (midnight to 2:00 pm) with no fishing allowed from 2:00 pm to midnight. Additional fishing closures would be implemented when critical temperature and flow criteria are met. This limits angling opportunity during the busiest time of year and would limit fishing opportunity for all species, not just brown trout. Angling pressure would be reduced during what is potentially the most stressful season for fish during the year. Implementing this regulation could increase fishing activities during the early morning hours and would be expected to displace many anglers to other waterbodies. This regulation could be biologically relevant to reduce brown trout mortality from angling (both from harvest and from delayed catch-and-release mortality).  

Status Quo

Maintain regulations currently in place. Since environmental conditions, such as flow and temperature, appear to limit brown trout populations more than angling, maintaining regulations already in place may be adequate to sustain wild populations until improvements to flow and habitat are achieved. Angling opportunity and angler displacement would be expected to remain at current levels. Additional drought restrictions (i.e., “hoot owl” restrictions) and fishing closures will still be implemented when critical temperature or flow criteria are met, typically during the late summer months.