Yellowstone closes three major rivers to fishing as dangerous heat threatens trout populations

Three prominent fishing rivers in Yellowstone National Park will remain closed to anglers following an announcement by National Park Service officials on July 15. The Madison, Firehole and Gibbon rivers—all situated on the park’s west and northwest sides near major tourist attractions including Old Faithful—face indefinite closure due to dangerously elevated water temperatures that threaten the park’s trout populations.

Peak water temperatures in the affected rivers have reached between 80 and 86 degrees Fahrenheit during daylight hours, creating conditions that are lethal to trout when combined with high air temperatures. Park officials have documented dead fish in the Firehole River and implemented 24-hour-a-day closures to protect native and wild trout fisheries until conditions improve. No heat-related restrictions currently apply to other park lakes, rivers or streams.

Steven J. Cooke, a biology professor at Carleton University in Ottawa, Ontario, explained that trout are ectothermic creatures whose body temperatures match their surrounding water. At elevated temperatures, these fish cannot extract sufficient oxygen and may not survive even after being released by anglers, he said in comments to Fox News Digital.

Cooke predicted that such closures will become increasingly common and urged anglers to adopt better catch-and-release practices by reducing fight time and minimizing air exposure. He noted similar patterns affecting muskellunge anglers in the Midwest and Atlantic salmon anglers in the Northeast, and supports fishing regulations in national parks to preserve sensitive ecosystems.

Yellowstone has maintained a reputation as a premier fishing destination for over 150 years, with park regulations designed to maintain native fish populations, genetic integrity and recreational fishing opportunities for visitors.