A look inside Montana FWP’s efforts to protect fish during tough summers

Hot, dry summers and reduced snowpack are now common in Montana. As these conditions become more common, Montana Fish, Wildlife & Parks has built a Toolbox of tools to protect trout and other native fish when rivers run low and water warms.

FWP says the challenges are clear: trout need cold, oxygen-rich water to make it through the summer, but long dry spells paired with shrinking snowpack threaten the rivers, streams, and lakes that provide it. That puts stress not only on fish but also on the ecosystems and people who depend on them.

To manage these pressures, FWP uses a layered approach—temporary restrictions in some cases, long-term water management in others. The agency says the goal is always the same: safeguard aquatic ecosystems while maintaining angling opportunities and balancing the needs of Montana’s water users.

Hoot-owl restrictions

The most visible tool for anglers is the “hoot-owl” restriction. This rule limits fishing to the cooler morning hours and shuts down angling after 2 p.m. Water temperature is the key factor. Restrictions usually take effect when the water temperature reaches 73 degrees for three consecutive days. For sensitive species like cutthroat and bull trout, the threshold is lower—66 degrees.

The science behind the rule is straightforward. Warm water holds less oxygen, meaning fish already stressed by high temperatures may not recover if caught and released. By reducing fishing pressure during the hottest parts of the day, FWP gives them a chance to survive.

Angling closures

When rivers shrink further, FWP may go beyond restrictions and close stretches entirely. Extremely low flows reduce available habitat, leaving juvenile fish without safe areas to grow and adults competing for limited food and cover. This can affect not just individual fish but entire populations.

Water program management

Beyond direct angling rules, FWP operates a water program designed to keep rivers flowing. Staff track stream flows statewide as they drop after snowmelt runoff fades. When flows fall below legal thresholds, the agency can exercise instream flow water rights. These rights allow FWP to require junior water users to stop diverting water.

In 2025, that meant calls on the Blackfoot, Gallatin, Marias, Smith, Shields, and other rivers. While often sensitive in communities, these decisions follow a clear, documented process. FWP prioritizes transparency by detailing the process and rationale behind calls on its website.

Collaborative drought planning

FWP also highlights the importance of collaboration. Drought plans have been developed for rivers like the Jefferson, Blackfoot, and Big Hole, where irrigators, landowners, and anglers work together under a “shared sacrifice” model. As water declines, each group gives a little—irrigators reduce withdrawals, while anglers face restrictions or closures.

Balancing short-term and long-term protection

FWP notes that some tools, like hoot-owl restrictions, are short-term measures aimed at helping fish survive the peak stress of summer heat. Other measures, such as managing instream flow rights, influence the long-term health of fish populations and aquatic ecosystems. Both, the agency says, are necessary to sustain Montana’s fisheries in the future.

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For FWP, the work is a balancing act: protect the fish, support the ecosystem, and maintain angling opportunities that are central to Montana’s way of life.