# US western river trout protection amid heat, fire > Live situation record from CLSTR: https://clstr.news/situations/us-western-river-fishing-closures-due-to-heatwave > Updated: 2026-08-03T00:54:12.000Z. Sources: 29. Developments: 6. Montana Fish, Wildlife & Parks extended its daily “hoot‑owl” fishing restrictions on July 29 2026 for the Big Hole, Blackfoot, Clark Fork and Bitterroot systems after water temperatures repeatedly hit 73 °F, and kept full‑day closures within 100 yards of the mouths of Fish Creek, Rattlesnake Creek and the St. Regis River to protect bull trout. Yellowstone National Park now closes all rivers to fishing between sunrise and 2 p.m., a rule that will stay in place until water temperatures and stream flows improve. The park’s afternoon bans echo similar measures in Montana, where 24 rivers covering about 1,200 miles are subject to the “hoot‑owl” closures. Colorado Parks and Wildlife has instituted voluntary closures on more than 400 miles of river and warned that mandatory bans could be triggered if water temperatures rise above 71 °F, streamflows fall below 50 % of average, or dissolved‑oxygen levels drop under 6 ppm. Recent readings on the Colorado, Rio Grande and Arkansas rivers have already exceeded 70 °F, a threshold that markedly increases mortality for catch‑and‑release trout. Arizona Game and Fish officials are urging anglers to seek cooler, higher‑elevation waters as valley streams become too warm for safe fishing. By the end of July, heat‑driven restrictions spread across the U.S. West. Colorado imposed afternoon bans on 19 rivers (≈635 miles), describing the situation as unprecedented. Officials link the pattern to a warming climate, an unusually dry winter and widespread drought, making such protective bans increasingly routine throughout the region. By July 31, record heat pushed water temperatures to lethal levels for trout, prompting wildlife agencies to broaden hour‑based bans. Montana expanded its afternoon “hoot‑owl” closures to more than 1,200 miles of streams, while Colorado’s restrictions now cover 19 rivers. Yellowstone widened its sunrise‑to‑2 p.m. ban to all park waterways. ## Claims - Wildlife officials are banning fishing during certain hours on rivers and streams across the U.S. West. (corroborated by 9 sources) - Yellowstone National Park has closed all rivers to fishing between 2 p.m. and sunrise. (corroborated by 8 sources) - Record summer heat has driven water temperatures to lethal levels for trout. (corroborated by 8 sources) - Human‑caused climate change is increasing temperatures and drought, making fishing closures more frequent. (corroborated by 8 sources) - Colorado has imposed restrictions on 19 rivers totaling 635.5 miles this summer, a situation state officials say is unprecedented. (corroborated by 7 sources) - Montana Fish, Wildlife and Parks has restrictions on 24 rivers covering about 1,200 miles as of July 28. (corroborated by 7 sources) - Colorado Parks and Wildlife has voluntary fishing closures on more than 400 miles of river and may impose mandatory closures if water temperatures exceed 71 °F, streamflows drop below 50 % of average, (corroborated by 2 sources) - Water temperatures on the Colorado, Rio Grande and Arkansas rivers have exceeded 70 °F, a level that significantly raises mortality for catch‑and‑release trout. (corroborated by 2 sources) - Montana Fish, Wildlife & Parks will implement daily 'hoot‑owl' fishing restrictions starting July 29 on specific rivers and creeks because water temperatures have reached at least 73 °F for three days (single source) - Montana will also enforce full‑day closures within a 100‑yard radius of the mouths of Fish Creek, Rattlesnake Creek and St. Regis River to protect bull trout (single source) - Introducing non‑native predatory fish such as pike or bass into Montana waters without authorization is illegal and punishable with fines (single source) - Illegal fish introductions threaten Montana’s blue‑ribbon trout fisheries and can eliminate native cutthroat and westslope populations (single source) ## Timeline ### 2026-08-03: Western US Trout Rivers Face Heat-Driven Fishing Closures Heat is prompting routine fishing closures on western US trout rivers, with Yellowstone, Colorado and Montana using temperature triggers, while the Missouri River remains open this August. 2 sources. https://clstr.news/cluster/western-us-trout-rivers-face-heat-driven-fishing-closures ### 2026-07-31: US Western Rivers Face Heat-Driven Fishing Closures Heat waves in the U.S. West have forced wildlife agencies to impose afternoon fishing bans on major rivers, including Yellowstone and Montana streams, to protect trout from lethal temperatures. 2 sources. https://clstr.news/cluster/us-western-rivers-face-heat-driven-fishing-closures ### 2026-07-29: Yellowstone expands fishing closures amid extreme heat across western rivers Yellowstone, Montana and Colorado have imposed extensive fishing closures as record heat drives river temperatures above 70 °F, threatening trout; Arizona urges anglers to fish in cooler high‑country waters. 16 sources. https://clstr.news/cluster/us-west-fishing-closures-imposed-as-record-heat-threatens-trout ### 2026-07-27: Montana and Colorado Implement New Trout Conservation Measures Amid Heat, Fire and Illegal Fish Introductions Montana adds heat‑related fishing limits and bull‑trout closures, warns against illegal predatory fish introductions, while Colorado rescues 103 genetically unique cutthroat trout from a wildfire‑threatened cre 4 sources. https://clstr.news/cluster/montana-and-colorado-implement-new-trout-conservation-measures-amid-heat-fire-and-illegal-fish-intro ### 2026-07-24: Yellowstone National Park shuts three rivers to fishing amid heat Yellowstone National Park closed the Madison, Firehole and Gibbon rivers to fishing on July 15 because water temperatures of 80‑86 °F threatened trout. 2 sources. https://clstr.news/cluster/yellowstone-national-park-shuts-three-rivers-to-fishing-amid-heat ### 2026-07-16: Heatwave Forces Fishing Closures on Colorado River System and Yellowstone Rivers Heatwave conditions have led Colorado and Yellowstone officials to close major rivers to fishing as low flows and extreme temperatures threaten trout populations. 5 sources. https://clstr.news/cluster/heatwave-forces-fishing-closures-on-colorado-river-system-and-yellowstone-rivers --- Cite as: US western river trout protection amid heat, fire. CLSTR, https://clstr.news/situations/us-western-river-fishing-closures-due-to-heatwave