Anglers on the Big Hole River near the Powerhouse fishing access site on Aug. 2, 2023. (Photo by Blair Miller, Daily Montanan)
While several fishing restrictions have been lifted from Montana rivers during the past couple weeks because of cooler temperatures, the Big Hole River will be closed to fishing in its entirety starting at midnight Saturday morning because of low flows and an expected spike in daily high temperatures.
Montana Fish, Wildlife and Parks said persistent low river flows, high water temperatures and an “unseasonably warm and dry forecast” led to the full closure decision. FWP implements hoot-owl restrictions and fishing closures when rivers reach certain temperature thresholds that can be harmful to cold-water fish like trout.
U.S. Geological Survey data showed Friday afternoon that water temperatures on the Big Hole ranged from 62 degrees to 70 degrees on various parts of the river, with the warmer temperatures near Twin Bridges on the lower end of the river.
Daily high temperatures in Wise River are forecast to be in the mid-80s for the next several days, at least until Tuesday, when rain and a daily high of 70 is currently forecast. Temperatures will be several degrees warmer further downriver.
During the past week and a half, FWP has lifted hoot-owl restrictions on the Beaverhead, Ruby, Smith, Jefferson, Bitterroot, Clark Fork, and portions of the Madison rivers as cooler temperatures and some rain moved through Montana. During parts of the summer, hoot-owl restrictions have been placed on rivers across the state, from the Yellowstone to the North Fork Flathead River.
But the only remaining closures and restrictions are on the Big Hole, Madison and Sun rivers. Along with the Big Hole closure, the Madison has hoot-owl restrictions from Hebgen Reservoir up to Yellowstone National Park and from the NorthWestern Energy powerhouse to where it meets the Jefferson River. The Sun River has hoot-owl restrictions from the mouth of Muddy Creek to the Highway 287 bridge.
Portions of the Big Hole River have been closed since early August. The river is one of particular focus for FWP and conservationists, along with others in the Jefferson basin, as researchers study what is contributing to declining trout populations in the basin and sickening fish with lesions and other abnormalities.