Yellowstone National Park has implemented emergency fishing closures on the Madison, Firehole, and Gibbon rivers due to dangerously high water temperatures that officials say are lethal to trout. The National Park Service announced the closures on July 15, stating they will remain in effect until conditions improve.
Peak water temperatures in the affected rivers have recently ranged from 80 to 86 degrees Fahrenheit during the day. These high temperatures, combined with warm air, create conditions that can kill trout. Reports of dead fish have emerged from the Firehole River, underscoring the severity of the situation.
The Madison, Firehole, and Gibbon rivers are located on the west and northwest sides of the park. The Firehole River flows through the popular Old Faithful area. These closures are in effect 24 hours a day and are intended to protect the park's native and wild trout populations.
According to Steven J. Cooke, a biology professor at Carleton University, fish are ectotherms, meaning their body temperature matches their environment. At high temperatures, trout have difficulty obtaining sufficient oxygen and may not survive after being released, especially after a prolonged fight. Cooke noted that such closures are likely to become more common due to warming conditions.
Yellowstone National Park has a long history as a destination for anglers, with its fisheries supporting recreational opportunities for over 150 years. The park's fishing regulations are designed to maintain the abundance and genetic integrity of native fish, preserve the overall ecological health of the park, and provide a recreational fishery for visitors.
While these three rivers are currently closed to fishing, officials stated that there are no similar heat-related restrictions on other bodies of water within the park. Visitors planning to fish in Yellowstone are advised to check current regulations and conditions before their trip. In a separate incident, two tourists were observed trespassing near the Grand Prismatic Spring on July 18, approaching the scalding hot spring outside designated boardwalks, highlighting visitor safety concerns in the park.